Know Your Enemy_ Phishing

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Know your Enemy: Phishing

hind the Scenes of Phishing Attacks

imary Authors

vid Watson:[email protected]

orsten Holz: [email protected]

en Mueller: [email protected]

st Modified: 16th May 2005

ishing is the practice of sending out fake emails, or spam, written to appear as if they have been sent by banks or other reputable organisations, with the intent of luring the recipient into

vealing sensitive information such as usernames, passwords, account IDs, ATM PINs or credit card details. Typically, phishing attacks will direct the recipient to a web page designed tomic a target organisation's own visual identity and to harvest the user's personal information, often leaving the victim unaware of the attack. Obtaining this type of personal data is attractive to

ckhats because it allows an attacker to impersonate their victims and make fraudulent financial transactions. Victims often suffer significant financial losses or have their entire identity stolen,

ually for criminal purposes. This KYE white paper aims to provide practical information on the practice of phishing and draws on data collected by the German Honeynet Projectand UK

neynet Project. This paper focuses on real world incidents that the Honeynet Project has observed in the wild, but does not cover all possible phishing methods or techniques. Attackers are

nstantly innovating and advancing, and there are likely to be new phishing techniques already under development or in use today.

ter a brief introduction and background, we will review the actual techniques and tools used by phishers, providing three examples of empirical research where real-world phishing attacks

re captured using honeynets. These incidents will be described in detail and include system intrusion, phishing web site preparation, message propagation and data collection. Common

hniques and trends are then analysed, including the growing integration of phishing, spamming, and botnets. Examples of the malware used by phishers to automate harvesting of email

dresses and sending of spam email are reviewed, and we also present our observations on network scanning techniques and how compromised machines are used to spread phishing emails

d other spam. Finally, we conclude this paper with an overview of the lessons learned in the last six months and suggest further research topics.

is white paper includes extensive amounts of supporting information, with many hyperlinks to more detailed data on specific attacks available inline. Lastly, no confidential personal data was

lected in the process of this research. In some cases, organizations involved in phishing attacks were contacted directly, or the incident data was forward to local CERTs.

ntroduction

cking others into giving out passwords or other sensitive information has a long tradition in the attacker community. Traditionally this activity has been performed through the process of social

gineering. In the 1990s, with the increasing growth in interconnected systems and the popularity of the Internet, attackers started to automate this process and attack the mass consumer

arket. The first systematic research to cover such activity was published in 1998 by Gordon and Chess (Sarah Gordon, David M. Chess: Where There's Smoke, There's Mirrors: The Truth

out Trojan Horses on the Internet, presented at the Virus Bulletin Conference in Munich, Germany, October 1998). Gordon and Chess were researching malware on AOL, but they were

ed with phishing attempts instead of the expected trojan horse attacks. The term phishing ("password harvesting fishing") describes the fraudulent acquisition, through deception, of sensitive

rsonal information such as passwords and credit card details by masquerading as someone trustworthy with a real need for such information. A phishing message described by Gordon and

essis shown below:

ctor 4G9E of our data base has lost all I/O functions. When your account

gged onto our system, we were temporarily able to verify it as a

gistered user. Approximately 94 seconds ago, your verification was made

id by loss of data in the Sector 4G9E. Now, due to AOL verification

otocol, it is mandatory for us to re-verify you. Please click 'Respond' and

-state your password. Failure to comply will result in immediate account

letion.

rly phishing attacks were primarily aimed at gaining access to the victim's AOL accounts, or occasionally at obtaining credit card data for fraudulent purposes (e.g. to make illegal purchases

th this information). Often the phishing messages contained a simple ruse to trick unskilled computer users and relied heavily upon the victims innate sense of trust in "automated" system

nctions or (apparent) figures of authority. As demonstrated in the previous example, this could be a story about a broken hardware device or the failure of a database, and most normal system

ers would take at face value any reasonably official-looking or highly urgent technical request that appeared to offer them assistance. Users were usually prompted to enter sensitive

ormation quickly to avoid a serious problem, for example via the phrase "[...] and re-state your password. Failure to comply will result in immediate account deletion". To avoid

tentially dire consequences the victims often complied immediately, unknowingly providing the social engineer with the credentials they required. Anecdotal evidence suggested that the culprits

ually were acting alone or in small, unsophisticated groups. Literature often portrays early phishers as adolescents desiring account data for causing mischief and to make long distance phone

ls, usually with little high level organisation or malice.

day, the preferred strategy chosen by phishers is to bulk email their lures to as many end users as possible whilst masquerading as a trusted brand - usually one with whom the phisher hopes

re is a chance that the victim already trusts. A request for urgent action is sent, often ironically to protect the user's confidential data from malicious activities, and this spoof email will contain

obscured link to a remote web-page that masquerades as the public web site of the target brand. The phisher hopes that victims will be tricked into submitting their credentials into a fake, but

parently legitimate looking "official" web interface for the trusted brand. Examples of the organisations being targeted by phishers include many well-known banks, credit card companies orll known Internet traders requiring regular payments (e.g. eBay and PayPal). Numerous examples of phishing emails targeting customers can be found at the Anti-Phishing Working Group

b site, which has a archive of phishing emails, many of which illustrate the high degree of accuracy with which phishers can trick innocent users into believing they are accessing a legitimate

b interface.

llowing this brief introduction to the concepts of phishing, we will now review the actual techniques and tools we have captured during phishing attacks observed in the wild. If you are

erested in further background on phishing, we have prepared this page of detailed background information.

Tools and Tactics

ishing attacks generally rely on a number of simple tools and techniques to trick unsuspecting users. The underlying infrastructure to support a phishing scam may be as basic as a simple

pied HTML page uploaded to a freshly compromised web server and a server side script to process any user input data, or it may involve more complex web sites and content redirection,

t generally the objectives are the same - to set up a fake web presence for a trusted brand with the necessary back end capabilities to process user input data and make it available to the

acker. Using modern HTML editing tools it is very easy to produce a web site mimicking a target organisation, and poorly secured web servers can easily be located and compromised if an

acker is not adverse to scanning entire portions of Internet IP address space in the search for vulnerable target hosts. Once compromised, even home PCs can make effective hosts forishing web sites, so not only well known corporate or academic systems are targeted. Attackers are often indiscriminate in their choice of target computers, purely selecting large IP address

cks to scan at random for a particular exploitable security vulnerability.

nce a phisher has established a realistic and convincing fake web site that mimics a trusted brand, their main challenge is how to divert users of a legitimate web site to the fake web site

tead. Unless the phisher has the ability to alter the DNS for a target web site ( DNS poisoning) or somehow otherwise redirect network traffic (a technique sometimes referred to as

arming), they must instead rely on some form of content level trickery to lure unfortunate users to the fake web site. The better the quality of the lure, and the wider the net that can be thrown,

greater the chance of an innocent user mistakenly accessing the fake web site (and in the process potentially providing the phisher with the victim's credentials or other personal data).
http://isc.sans.org/presentations/dnspoisoning.phphttp://www.research.ibm.com/antivirus/SciPapers/Smoke/smoke.htmlhttp://www.ukhoneynet.org/mailto:[email protected]:[email protected]://en.wikipedia.org/wiki/Pharminghttp://isc.sans.org/presentations/dnspoisoning.phphttp://www.honeynet.org/details/phishing-background.htmlhttp://www.antiphishing.org/phishing_archive.htmlhttp://www.antiphishing.org/http://www.research.ibm.com/antivirus/SciPapers/Smoke/smoke.htmlhttp://www.ukhoneynet.org/http://www-i4.informatik.rwth-aachen.de/lufg/honeynetmailto:[email protected]:[email protected]:[email protected]


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nfortunately for the attacker, when they target an individual organisation (such as a bank or trusted retailer), the phisher probably does not have any information about who on the Internet is a

stomer of the target organisation and therefore who might be most receptive to a particular lure. Although the attacker could post hyperlinks pointing to the fake web site on chat rooms and

ums related to the target brand (such as a technical support web site or community discussion group), it is likely that the target organisation would be notified reasonably quickly and the

fending hyperlinks removed or discredited before many victims had accessed the content and submitted their personal details. There would also be a significant risk that the target organisation

law enforcement agencies might trace and potentially shut down the fake web site. The phisher therefore requires a method of reaching the maximum number of potential victims with the

nimum amount of risk, and they have found their ideal partner in crime in the form of spam email.

ammers have databases containing many millions of active email addresses, so the latest mass emailing techniques can be employed to allow a phisher to distribute their lure to a very wide

dience with very low risk. Spam emails are often sent via compromised servers hosted in foreign countries, or via global networks of zombie PCs (botnets), so the likelihood of an individual

nder being traced is low. If an unsuspecting user receives an officially branded email that appears to have been sent by their bank which asks them to go to what appears to be the bank's

ual branded web site to change their online banking password for security reasons, they are much more likely to consider doing so than when confronted with standard spam emails about

velty products and links to unknown web sites. To increase the likelihood that a user will believe that an email is genuine, the phisher can employ a number of techniques to further improve the

ality of their attempted deception:

Using IP addresses instead of domain names in hyperlinks that address the fake web site. Many innocent users will not check (or know how to check) that an IP address is registered and

assigned to the target organisation that the branded fake web site claims to represent.

Registering similar sounding DNS domains and setting up fake web sites that closely mimic the domain name of the target web site (i.e. b1gbank.com or bigbnk.com instead of

bigbank.com), in the hope that users will mistake the fake domain name for the real domain name.

Embedding hyperlinks from the real target web site into the HTML contents of an email about the fake phishing web site, so that the user's web browser makes most of the HTTP

connections to the real web server and only a small number of connections to the fake web server. If the user's email client software supports auto-rendering of the content, their client

may attempt to connect automatically to the fake web server as soon as the email is read, and manual browsers may not notice the small number of connections to a malicious server

amongst the normal network activity to the real web site.

Encoding or obfuscating the fake web site URL. Depending on the method employed, many users will not notice or understand what has been done to a hyperlink and may assume it is

benign. One variant of this technique (IDN spoofing) is to use UnicodeURLs that render in browsers in a way that looks like the original web site address but actually link to a fake web

site with a different address.

Attempting to exploit weaknesses in the user's web browser to mask the true nature of the message content. Microsoft's Internet Explorer and Outlook applications have been particularly

vulnerable to such techniques (such as the address bar spoofingor IFrame elementbugs).

Configuring the fake phishing web site to record any input data that the user submits (such as usernames and passwords), silently log them and then forward the user to the real web site.

This might cause a "password incorrect, please retry" error or even be totally transparent, but in either situation many users will not be overly worried and put this event down to their ownpoor typing, rather than intervention by a malicious third party.

Set up a fake web site to act as a proxy for the real web site of the target brand, covertly logging credentials that are not encrypted using SSL (or even registering valid SSL certificates

for spoof domains).

Redirect victims to a phishing web site by first using malware to install a malicious Browser Helper Objecton their local PC. BHOs are DLLs designed to customize and control the

Internet Explorer web browser, and if successful, victims can be tricked into believing they are accessing legitimate content when in fact they are accessing a fake web site.

Use malware to manipulate the hostsfile on a victim's PC that is used to maintain local mappings between DNS names and IP addresses. By inserting a fake DNS entry into a user's

hostsfile, it will appear that their web browser is connecting to a legitimate web site when in fact it is connecting to a completely different web server hosting the fake phishing web site.

ue to the relatively complex nature of many e-commerce or online banking applications, which often employ HTML frames and sub-frames or other complex page structures, it may be difficult

an end user to easily determine if a particular web page is legitimate or not. A combination of the techniques listed above may mask the true source of a rendered web page and an

suspecting user might be tricked into mistakenly accessing the phisher's fake web site, unknowingly divulging their authentication credentials or other personal data. At this point the phisher will

free to make use of the user's accounts or electronic identity as required, and the user becomes another victim of a successful phishing attack.

Real World Phishing Techniquesry often Internet users become aware of phishing attacks by receiving spoof emails themselves or viewing a recorded copy of a malicious web site below the headlines on a technology news

e, long after the server temporarily hosting the phishing content has been taken down. These events tend to be viewed in isolation and purely from the perspective of the victim. One of the

ajor benefits that honeynet technology can offer is the capability to capture all activity from the perspective of the attacker, allowing security analysts to build up a more complete understanding

the entire life span of a phishing attack. Members of the Honeynet Project's Research Allianceare fortunate enough to have captured a number of rich data sets that can help to illustrate the

ges of such an attack, from initial compromise and phishing web site set up through to mass emailing and victim data capture. Three different examples of typical real world phishing

hniques are presented and reviewed below.

Phishing Technique One - Phishing Through Compromised Web Servers

ost phishing attacks that we have observed in the wild involve attackers breaking in to vulnerable servers and installing malicious web content. Honeynet technology allows us to capture in

tail the typical life cycle of a phishing attack, and in general terms the flow of events we have observed during such incidents are as follows:

Attackers scan for vulnerable serversServer is compromised and a rootkit or password protected backdoor installed

Phishers gain access to the server through this encrypted back door

If the compromised server is a web server, pre-built phishing web sites are downloaded

Some limited content configuration and web site testing is performed (potentially revealing the phisher's true IP address when they first access the web server)

Mass emailing tools are downloaded and used to advertise the fake web site via spam email

Web traffic begins to arrive at the phishing web site and potential victims access the malicious content

ten the time taken for this incident life cycle is only a matter of hours or days from when the system is first connected to the Internet, and our research suggests that such activity is taking place

many servers and targeting many organisations at once. We will illustrate these theories using data recorded during two incidents that are typical of common phishing attacks, using one

ident observed by the German Honeynet Project and one incident observed by the UK Honeynet Project. In each case, vulnerable Linux honeypots were deployed by Honeynet Research

liance members. The subsequent compromise of both honeypots shared a similar modus operandi: the vulnerable honeypots were scanned and compromised in quick succession, with pre-

ilt phishing web sites and mass emailing tools for sending spam emails being uploaded and used by the attackers. Rootkits and IRC servers were also installed during these attacks, something

commonly observed in other similar incidents. The compromised honeypots were also used for several different purposes in addition to phishing: as an IRC bot by Romanian attackers and

o as a scanner to locate and attack additional vulnerable computers (although the honeynet architecture prevented the attackers from successfully exploiting other servers from the

mpromised honeypots). Some interesting differences were also apparent, not least in the case of the UK incident, where several different groups accessed the compromised honeypot at theme time, making forensic analysis more complicated. For the sake of brevity, we have not included the details of these specific attacks in this paper and have only covered the lessons learned

d how they apply to phishing. If you would like to review more details about the specific attacks, the following information is available:

Overview of Honeynet configurations

Details of German honeypot compromise

Details of UK honeypot compromise (timeline)

Details of UK honeypot compromise (content analysis)
http://www.honeynet.org/details/uk-analysis.htmlhttp://www.honeynet.org/details/uk-timeline.htmlhttp://www.honeynet.org/details/de-detailed.htmlhttp://www.honeynet.org/details/index.htmlhttp://www.honeynet.org/alliancehttp://msdn.microsoft.com/library/en-us/dnwebgen/html/bho.asphttp://www.kb.cert.org/vuls/id/960454http://secunia.com/internet_explorer_address_bar_spoofing_test/http://en.wikipedia.org/wiki/Unicodehttp://secunia.com/advisories/14163http://www.honeynet.org/papers/bots


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e table below shows a summary of the key factors and differences between the incidents:

Data DE Incident UK Incident

ompromised honeypot Redhat Linux 7.1 x86. Redhat Linux 7.3 x86.

ocation German corporate network. UK ISP data centre.

Attack method "Superwu" autorooter. "Mole"mass scanner.

Vulnerability exploited Wu-Ftpd File globbing heap corruption vulnerability

(CVE-2001-0550).

NETBIOS SMB trans2open buffer overflow (CAN-

2003-0201).

evel of access gained Root. Root.

Rootkit installed Simple rootkitthat backdoors several binaries. SHV4 rootkit.

robable attackers Unknown. Multiple groups from cable modem IP ranges in

Constanta region of Romania.

Web site activity Multiple pre-built phishing web sites downloaded

targeting eBay and major US banks.

Pre-built phishing web site downloaded targeting a

major US bank.

erver side processing PHP scriptto validate user input. PHP scriptwith more advanced user input validation

and data categorisation.

mail activity Tried to send spam (example 1, example 2), but

blocked by Honeywall.

Only test emails sent, potentially to fellow phishers.

Improved syntax and presentation.

Mass emailing method Basic PHP scriptfrom medium sized input list of email

addresses.

Basic PHP script from small input list of email

addresses - possibly just a test.

Victim traffic reached honeypot No, spam advertisement and access to phishing web

site blocked.

Yes. 265 HTTP requests in 4 days, not due to spam

sent from this server (no customer details were

compromised).

om observing the phisher's keystrokes in both incidents (captured using Sebek), it is clear that the attackers connected to pre-existing back doors and immediately went to work deployingir phishing web sites. The attackers appeared to be familiar with the server environment, suggesting they were part of the group who originally compromised the honeypots, and that the

ishing attempt was fairly well organised. As the uploaded web content often referred to other web servers and IP addresses, it is also likely that such activity was probably occurring on

ultiple servers at once.

nalysis of the phishing web site content downloaded by attackers during these incidents makes it clear that phishers are simultaneously targeting many well known online brands. Well

nstructed and officially branded pre-built fake web sites are routinely being deployed onto compromised servers - often targeting multiple organisations via separate "micro sites", with

parate web server document roots, along with the necessary tools to propagate spam emails to potential phishing victims. Directory listings observed during FTP sessions also confirm that the

ackers were heavily involved in spam and phishing activities, revealing pre-built web content and message delivery tools stored on a central server and appearing to target at least eBay, AOL,

d several well known US banks in the case of the UK incident. These individual phishing attacks are unlikely to be isolated events, as the spam emails sent during the incidents often directed

tims to a different web server than the compromised honeypot. This indicates that phishers are running multiple fake web servers and sending spam from multiple systems at once. Parallel

ishing operations are also indicated by the timing of the first inbound HTTP request for phishing content after the UK honeypot was compromised:

04-07-23 21:23:14.118902 XXX.XXX.XXX.XXX -> 10.2.2.120 HTTP GET /.internetBankingLogon HTTP/1.1

is inbound HTTP request to the honeypot occurred before the attackers had finished setting up the fake online banking content on the honeypot, and confirms the hypothesis that the attacker

ew in advance that this server was available for use as a phishing web site. Spam messages advertising the new phishing web site were already being emailed to victims from another host,

en whilst the attacker was setting up the new phishing web site.

e were surprised by the number and range of source IP addresses making inbound HTTP requests to the compromised honeypot for the fake online banking content. The graph below shows

number of unique and repeat HTTP requests from individual IP addresses to the UK phishing web site before the honeypot was disconnected to protect end users (and the incident details

gged with the targeted bank):

mage:images/HTTP%20access.JPG size=full]

breakdown of the source top level DNS domains, countries and host operating systems accessing the phishing content on the UK honeypot can be found here. Note that before the honeypot

s taken offline for forensic analysis, although web traffic for the phishing web site did arrive at the UK honeypot, no HTTP POST requests were made to the PHP script that processes users'

ta and therefore no user data was compromised during this phishing attack. In all the incidents discussed in this white paper, either the target organisation was notified of the incident and any

evant data was made available to them on request, or the local CERT was notified of any malicious activity. In all cases no compromised victim personal data was captured by Honeynet

oject or Research Alliance members.

ta from these two example incidents suggests that phishers are active and organised, moving quickly between compromised computer systems and simultaneously targeting multiple wellown brands. It also appears that a number of email users are regularly being tricked into accessing fake web interfaces for organisations such as online banks or retailers, and risk becoming

tim's of phishing attacks.

Phishing Technique Two - Phishing Through Port Redirection

November 2004, the German Honeynet Project deployed a classic GenII honeynet with a Redhat Linux 7.3 honeypot. Although this is a relatively old operating system release and an easy

get for attackers, it surprisingly took around 2.5 months before the honeypot was successfully compromised - a marked contrast with the relatively quick compromise of the honeypots
http://www.honeynet.org/papers/gen2/index.htmlhttp://www.honeynet.org/breakouts/uk-phishing-victims.htmlhttp://www.honeynet.org/details/uk-analysis.htmlhttp://www.honeynet.org/tools/sebek/http://www.honeynet.org/details/de-detailed.html#mmhttp://www.honeynet.org/tools/cdromhttp://www.honeynet.org/details/de-honeynet_files/bankB-mail.htmlhttp://www.honeynet.org/details/de-honeynet_files/bankA-mail.htmlhttp://www.honeynet.org/details/uk-analysis.htmlhttp://www.honeynet.org/details/de-honeynet_files/phishing-validation.htmlhttps://tms.symantec.com/members/AnalystReports/030929-Analysis-SHV4Rootkit.pdfhttp://www.honeynet.org/details/de-detailed.html#rootkithttp://cve.mitre.org/cgi-bin/cvename.cgi?name=2003-0201http://cve.mitre.org/cgi-bin/cvename.cgi?name=2001-0550http://www.honeynet.org/examples/mole.txt


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cussed in the incidents above. More information on this trend can be found in a previous KYE white paper "Know your Enemy: Trends".

n January 11th 2005, an attacker did successfully compromise the honeypot, using an exploit for the OpenSSL SSLv2 Malformed Client Key Remote Buffer Overflow Vulnerabilitypresent in

default Redhat Linux 7.3 distribution. This incident was unusual in that once the attacker had gained access to the compromised system, no phishing content was uploaded directly. Instead,

attacker installed and configured a port redirection service on the honeypot.

is port redirection service was designed to re-route HTTP requests sent to the honeypot web server to another remote web server in a transparent manner, potentially making the location of

content source harder to trace. The attacker downloaded and installed a tool called redir on the honeypot, which was a port redirector utility designed to transparently forward incoming

CP connections to a remote destination host. In this incident the attacker configured the tool to redirect all incoming traffic on TCP port 80 (HTTP) of the honeypot to TCP Port 80 (HTTP)

a remote web server in China. Interestingly, the attacker did not bother to install a rootkit to hide their presence on the honeypot, which suggests that the attacker did not value the

mpromised server too highly and that they were not particularly worried about being detected.

e command used by the attacker to establish port redirection was:

dir --lport=80 --laddr= --cport=80 --caddr=221.4.XXX.XXX

addition, the attacker modified the Linux system start up file /etc/rc.d/rc.local to ensure that the redir port redirector service would be restarted if the honeypot system was rebooted,

proving the chance of survival for their port redirection service. They then began to send out spam phishing emails which advertised the honeypot, an example of which can be found here

ote that relevant sensitive information has been obfuscated).

further investigate the activities for the phisher, members of the German Honeynet Project intervened and covertly modified the configuration of the attacker's redir tool installed on the

neypot, enabling logging within the redir application itself, to more easily observe how many people received a spam email advertising the honeypot and then clicked on a hyperlink to access

transparently redirected phishing content. Within a period of about 36 hours, 721 unique IP addresses were redirected, and once again we were surprised by how many users were

parently being tricked into accessing such content through phishing emails. An analysis of the IP addresses accessing the port redirector honeypot can be found here(note that this information

s been sanitized to protect the users who accessed the phishing content, and again only IP data was logged during this research. No confidential user data was captured).

summary timeline of the incident is provided below:

Date / Time Event

st Nov 2004 First network probe data of honeypot

1th Jan 2005 - 19:13 Honeypot OpenSSLservice compromised, port redirector installed andphishing spamsent

1th Jan 2005 - 20:07 Web requestsfor phishing content begins to arrive at honeypot

3th Jan 2005 - 8:15 Honeypot taken offline for forensic analysis

Phishing Technique Three - Phishing Using Botnets

e recent white paper by the Honeynet Project called "KYE: Tracking Botnets" introduced a method to track botnets. A botnet is a network of compromised computers that can be remotelyntrolled by an attacker. Due to their immense size (tens of thousands of systems can be linked together), botnets can pose a severe threat to the community when used for Denial-of-Service

oS) attacks. Initial research in this area demonstrated that botnets are sometimes used to send out spam emails and can also be used for phishing attacks. During a study in October 2004,

mail security company CipherTrustsuggested that 70%of monitored phishing spam was sent through one of five active botnets, but our own observations suggest that many more botnets are

use for spam operations. Although not the analysis of one single incident, in this section we present our observations on the tools and techniques used by attackers engaged in phishing via

tnets.

ncident Timeline

uring the period between September 2004 and January 2005, the German Honeynet Project deployed a series of un-patched Microsoft Windowsbased honeypots to observe botnet activity.

n automated process was developed to allow honeypots to be repeatedly deployed, compromised and shutdown for forensic analysis. During this period over 100 separate botnets were

served and thousands of files were captured for offline analysis.

Analysisme versions of bot software captured during this research project provided the capability to remotely start a SOCKS v4/v5 proxy on a compromised host. SOCKS provides a generic proxy

chanism for TCP/IP-based networking applications (RFC 1928) and can be used to proxy most popular Internet traffic, such as HTTP or SMTP email. If an attacker with access to a botnet

ables the SOCKS proxy functionality on a remote bot, this machine can then be used to send bulk spam email. If the botnet contains many thousands of compromised hosts, an attacker is

n able to send massive amounts of bulk email very easily, often from a wide range of IP addresses owned by unsuspecting home PC users.

e lack of a central point of contact and the range of international boundaries crossed could make it very difficult to trace and stop such activity, making it of low risk, but potentially high

ward to spammers and phishers. Perhaps unsurprisingly, resourceful botnet owners have begun to target criminal activity and it is now possible to rent a botnet. For a fee, the botnet operator

ll provide a customer with a list of SOCKS v4 capable server IP addresses and ports. There are documented cases where botnets were sold to spammers as spam-relays: " Uncovered:

ojans as Spam Robots". Some captured bot software also implemented a special function to harvest email-addresses or to send spam via bots. The following listing shows some of the

mmands related to sending spam/phishing emails implemented in Agobot, a popular bot used by attackers and a variant regularly captured during our research:

harvest.emails - "makes the bot get a list of emails"

harvest.emailshttp - "makes the bot get a list of emails via HTTP"

spam.setlist - "downloads an email list"spam.settemplate - "downloads an email template"

spam.start - "starts spamming"

spam.stop - "stops spamming"

aolspam.setlist - "AOL - downloads an email list"

aolspam.settemplate - "AOL - downloads an email template"

aolspam.setuser - "AOL - sets a username"

aolspam.setpass - "AOL - sets a password"

aolspam.start - "AOL - starts spamming"
http://www.heise.de/english/newsticker/news/44879http://www.usatoday.com/tech/news/computersecurity/2004-07-07-zombie-pimps_x.htmhttp://rfc.net/rfc1928.htmlhttp://www.microsoft.com/http://newswww.bbc.net.uk/1/hi/technology/3762264.stmhttp://www.ciphertrust.com/http://www.honeynet.org/papers/bots/http://www.honeynet.org/breakouts/de-phishing-victims.htmlhttp://www.honeynet.org/examples/phishing-mail.txthttp://securityfocus.com/bid/5363/info/http://www.honeynet.org/breakouts/de-phishing-victims.htmlhttp://www.honeynet.org/examples/phishing-mail.txthttp://sammy.net/~sammy/hacks/redir-2.2.1.tar.gzhttp://securityfocus.com/bid/5363/info/http://honeynet.org/papers/trends/life-linux.pdf


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aolspam.stop - "AOL - stops spamming"

rther information about how these commands are implemented can be found herein a side note about the source code of bots. With the help of drone, a customised IRC client developed by

German Honeynet Project, we were able to learn more about how bots are used for spam/phishing email attacks by smuggling a fake client into a botnet using the connection data collected

ough the attacks against our honeynets. A number of typical examples of observed activity are shown below.

Example 1

ithin one particular botnet we observed an attacker who issued the following command (please note that the URLs have been obfuscated):

t0n3y> .mm http://www.example.com/email/fetch.php?4a005aec5d7dbe3b01c75aab2b1c9991 http://www.foobar.net/pay.html Joe did_u_send_me_this

e command .mm ("mass emailing") is a customized version of the generic spam.start command. This command accepts four parameters:

1. A URL for a file that contains several email addresses.

2. The web page to target within the spam email - this could be a normal spam web-page or a phishing web site.

3. The name of the sender.

4. The subject of the email.

this case, thefetch.phpscript returned 30 different email addresses every time it was invoked. To each of these recipients, an email message was constructed that advertised the second

rameter of the command. In this example, it pointed to a web-page which attempted to install an ActiveX component on the victim's computer.

Example 2

another botnet we observed the installation of Browser Helper Objects on a victim's PC:

OPIC] #spam9 :.open http://amateur.example.com/l33tag3/beta.html -s

e .open commands tells each bot to open the requested web-page and display it to the victim. In this case the web-page contained a Browser Helper Object (BHO) that would attempt to

tall itself on the victim's computer. As the channel name indicates, this botnet was also used for sending spam.

Example 3

another botnet we observed examples of spyware propagation:

tp://public.example.com/prompt.php?h=6d799fbeef3a9b386587f5f7b37f[...]

is link was found during analysis of captured malware. It directs the victim to the web-page of a company that offers "free ad delivery software which provides targeted advertising

fers". This web site contains several pages that try to install ActiveX components on visiting clients, presumably adware or spyware.

Common Themes

number of common themes were observed during our research into phishing attacks, and it is clear that attackers are employing a blend of tools and techniques to improve their chances of

ccess. We will now briefly review two such techniques - mass scanning and combination attacks.

Mass Scanning

nalysis of a number of compromised honeypots suggests that the systems were being attacked using automated attack scripts or exploits, often known as autorooters. In both the incidents

scribed in phishing technique one above, once the attackers had compromised the honeypots, autorooter toolkits were uploaded to the server. The attackers then attempted to scan large

nges of IP addresses for similarly vulnerable servers (using scanners called "superwu" in the German incident and "mole" in the UK incident). Captured attacker keystrokes from the UK

ident are show below, showing examples of the types of mass scanning activity attempted from compromised honeypots. Note that due to the honeynet configuration, hostile outbound traffic

s blocked and these attacks did not succeed.

tacker extracts scanner and attempts to scan class B network blocks:

004-07-18 15:23:31 bash 0]tar zxvf mole.tgz

004-07-18 15:23:33 bash 0]cd mole

004-07-18 15:23:38 bash 0]./mazz 63.2

004-07-18 15:24:04 bash 0]./mazz 207.55

004-07-18 15:25:13 bash 0]./scan 80.82

tacker attempts to exploit potentially vulnerable servers:

004-07-19 11:56:46 bash 0]cd mole

004-07-19 11:56:50 bash 0]./root -b 0 -v ns1.victim.net

004-07-19 11:57:26 bash 0]./root -b 0 -v 66.90.NNN.NNN

tacker returns later to check list of successfully compromised servers (the list was empty, due to the honeynet configuration):

004-07-23 08:13:18 bash 0]cd mole

004-07-23 08:13:20 bash 0]ls

004-07-23 08:13:25 bash 0]cat hacked.servers

tacker attempts to scan multiple class B network blocks and then test an exploit against a selection of targets:

004-07-24 10:24:17 bash 0]cd mole

004-07-24 10:24:19 bash 0]./scan 140.130

004-07-24 10:24:27 bash 0]./scan 166.80

004-07-24 10:25:36 bash 0]./scan 166.4

004-07-24 10:26:23 bash 0]./scan 139.93

004-07-24 10:27:18 bash 0]./scan 133.200

004-07-24 10:36:37 bash 0]./try 202.98.XXX.XXX

004-07-24 10:38:17 bash 0]./try 202.98.YYY.YYY

004-07-24 10:38:27 bash 0]./try 202.98.YYY.YYY
http://msdn.microsoft.com/library/en-us/dnwebgen/html/bho.asphttp://en.wikipedia.org/wiki/Activexhttp://www.honeynet.org/breakouts/bots-code.html


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the final example above, note that the hosts that the attacker attempts to compromise are not part of the IP address ranges scanned from this honeypot, which again provides evidence of well

ordinated and parallel mass scanning activity.

rther investigation of the mole.tgzfile downloaded by UK attackers revealed a number of text files in the root directory of the unpacked autorooter toolkit. These files included scan

nfigurations and logs of previous scanning activity for the "grabbb2.x and samba2.2.8 vulnerability". 42 cases of attacks against other hosts were present in these files, along with evidence

mass scanning of many class B network blocks, confirming that the observed incident was part of larger and more organised attack against similar systems. An example of the output from the

ole scanning tool, viewed from an attacker's perspective, can be found here.

nally, some of the mass scanning tools recovered from compromised honeypots do not appear to be in popular circulation, which suggests that the attackers had some level of development

d tool smith capabilities beyond basic script kiddy activity, or were part of a closed community that did not share their tools in public forums. Again, this suggests more organised attackers.

Combination Attacks

our research, we also observed that phishers are frequently combining the three attacking techniques we have observed and documented in this white paper, sometimes combining multiple

thods to provide redundancy and protect their phishing infrastructure through implementation of a two-stage networking configuration. The following diagram depicts a possible phishing

twork topology:

mage:images/phishing-setup.png size=full]

this example a central web server hosts the physical phishing content, often serving more then one web site (e.g. an eBay phishing-site in /ebay and a PayPal phishing-site in /paypal). Several

mpromised remote computers redirect incoming HTTP traffic on TCP port 80 to the central web server with the help of the redir port redirector. This has several advantages from an

acker's point of view when compared to a single phishing web site:

If the compromise of one of the remote redir hosts is detected, the victim will probably take the system offline and re-install it. This does not represent a major loss for the phisher because

the main phishing web site is still online and several other redir hosts continue to deliver HTTP traffic to the central web server.

If the compromise of the central phishing server is detected, this system will also be taken offline. Now the phisher can simply set up a new phishing site on a freshly compromised system

and then re-adjust the existing network of redir hosts to redirect traffic to the replacement central host. Using this technique, the whole network can be made available very quickly and

the phishing attacks can soon recommence.

A redir host is very flexible, since it can be easily reconfigured to point to another phishing web site. This decreases the time between initial system compromise and phishing web siteavailability, and increases the length of the attack window in which the phishing attacks can be performed.

e use of such techniques again suggests more organised and capable attackers, rather than the work of simple script kiddies. Similar operational models are often used by major web hosting

mpanies and high volume content providers.

Further Observations - Fund Transfer

ur research has also shed light on how phishers use captured information about bank accounts, for example, an account number with associated TAN (transaction number used in electronic

nking). Since foreign currency transfers are monitored by most banks, phishers cannot simply transfer large amounts of money from one country to another without alerting the financial

thorities. Phishers therefore have to use intermediaries to transfer money for them - in a two stage process the phisher transfers money from the victim's bank account to a bank account of an

ermediary in the same country. The intermediary then withdraws the money from their bank account (less a percentage remuneration for providing the service) and sends it to the phisher, for

ample by surface mail. Of course, the intermediary could be caught, but as the phisher's money is already in transit they do not face too much risk and can easily change to channel their funds

ough a replacement intermediary. An example email demonstrating some of the financial structures behind phishing attacks is show below:

llo!

finding Europe persons, who can Send/Receive bank wires

om our sellings, from our European clients. To not pay

XES from international transfers in Russia. We offer 10%

rcent from amount u receive and pay all fees, for sending

nds back.Amount from 1000 euro per day. All this activity

e legal in Europe.

ll this form: http://XXX.info/index.php (before filling

stall yahoo! messenger please or msn), you will recieve

ll details very quickly.

_______________________________________________________

r, europ?ische Personen findend, die Bankleitungen

von Senden/erhalten k?nnen unsere Verk?ufe, von

seren Kunden von Deutschland. STEUERN von internationalen

ertragungen in Russland nicht zu bezahlen. Wir

h?lt das Prozent des Angebots 10 % vom Betrag und

zahlt alle Schulgelder, um Kapital zur?ck zu senden.

trag von 1000 Euro pro Tag. Diese ganze T?tigkeit

t in Europa gesetzlich.

llen Sie diese Form: http://XXX.info/index.php (bevor

e F?llung Yahoo installiert! Bote bitte oder msn), Sie

cieve volle Details sehr.

ank you, FINANCIE LTD.

is is a poor translation from English to German, probably computer-generated, and it suggests that the attackers are not native English speakers. Since the money will be transferred to Russia,

attacker probably originated from this country. This behaviour is becoming increasingly common as phishing activities become more organised.

Honeysnap - An Incident Analysis Assistant

ne conclusion was immediately obvious when we started to analyse data from the UK honeynet compromise in phishing technique one above - due to multiple simultaneous attacks by different

ckhat groups, a significant amount of time would be required to extract and prepare the data from the network streams before more detailed analysis could take place. This data extraction

ocess is repetitive and tedious, and if carried out manually represents an inefficient use of valuable analysis time. An automated solution was required.

e honeysnapscript, written by David Watsonof the UK Honeynet Project, grew out of this idea and was designed to process honeynet data feeds on a daily basis and produce a simple

mmary output to direct later manual analysis. The honeysnapscript breaks down the data for each honeypot and provides lists of outbound HTTP and FTP GETs, IRC messages and Sebek

ystroke logs. TCP stream re-assembly for interesting connections is automated, as is extraction, identification and storage of files downloaded by FTP or HTTP, meaning that much of the

me-consuming preparatory work of incident analysis is removed, leaving the analysts free to concentrate on manually investigating key elements of an incident.Honeysnapalso provides an

tomated method for screening IRC traffic for interesting keywords (e.g. bank, account, password) and providing daily summary reports by email.

rrently honeysnapis a basic proof of concept UNIX shell script and the alpha release can be found here, whilst a set of sample honeysnapoutput can be found here. A modular and fully
http://www.honeynet.org/examples/honeysnap_sample1.txthttp://www.ukhoneynet.org/tools/honeysnapmailto:[email protected]://www.honeynet.org/examples/mole.txt


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pandable version written in Python is currently under development by members of the Honeynet Project and will be beta released to the community in June 2005.

Further Research

e information presented in this white paper suggests a number of potential avenues for future research in the area of phishing attacks and we would recommend further investigation of the

lowing subjects:

e would like to investigate if honeypots can be used to help in the fight against spammers and phishers. One possible research project would be to deploy additional honeypots of a type

gularly used in previously observed phishing attacks or tuned to present attractive targets to spammers (such as SMTP open relays). Analysis of further attacks against these systems would

p us to learn more about the anatomy of phishing attacks, particularly in the area of phishing using botnets, and to track the evolution of phishing techniques. Another research possibility

uld be to further develop the idea of honeypots and produce "client-side honeypots". This type of next-generation honeypot would actively participate in communication networks, for

ample, by automatically follow links in spam emails and accessing the target content. Client-side honeypots could idle in IRC-channels or share/download files viapeer-to-peer networks,

ther improving our knowledge about the type of threats present in these communication networks.

addition, we would like to investigate potential methods of countering or stopping phishing attacks. Since the time window between the start and end of a phishing attack is likely to be limited

a matter of only hours or days, and the source hosts are widely distributed, this is a difficult task. Current research efforts in this area (for example The AntiPhishing Groupand PhishReport)

ncentrate on collecting phishing emails received by end users. Whilst this is a viable approach, capture occurs at the final stage in the incident lifecycle. An automated approach to capturing

d responding to phishing attacks would be more desirable.

e suspect that accounts and passwords are being traded between blackhat groups, probably via IRC. Honeynet technology could be used to capture such communication and further

derstand phishing activities. In addition, phishing tools often appear to be downloaded from a number of regularly updated central web or FTP servers. Although more contentious, monitoring

such activity or contacting the system owners would help to prevent some phishing activity, and a framework for operating such research and potential countermeasures could be established.

rther work is required to improve the automation of incident analysis, particularly in automatic profiling of data captured during such attacks. Automation of traffic and IP address extraction,

verse DNS and IP block ownership lookups, per IP address or per domain traffic summaries and en-masse passive operating system fingerprinting would all be particularly useful when

alysing large data sets, as would a local forensic database of known hosts, attackers, attack signatures, message contents, etc. In the longer term, agreed standards for sharing such

ormation and a global forensic database to support analysis of distributed blackhat activities would be highly desirable and of significant benefit to the community.

Conclusions

this paper we have presented a number of real world examples of phishing attacks and the typical activities performed by attackers during the full lifecycle of such incidents. All the information

ovided was captured using high interaction research honeypots, once again proving that honeynet technology can be a powerful tool in the areas of information assurance and forensic analysis.

e analysed multiple attacks against honeypots deployed by the German and UK Honeynet Projects. In each incident phishers attacked and compromised the honeypot systems, but after the

ial compromise their actions differed and a number of techniques for staging phishing attacks were observed:

1. Setting up phishing web sites targeting well known online brands.

2. Sending spam emails advertising phishing web sites.

3. Installing redirection services to deliver web traffic to existing phishing web sites.

4. Propagation of spam and phishing messages via botnets

is data has helped us to understand how phishers typically behave and some of the methods they employ to lure and trick their victims. We have learned that phishing attacks can occur very

pidly, with only limited elapsed time between the initial system intrusion and a phishing web site going online with supporting spam messages to advertise the web site, and that this speed can

ake such attacks hard to track and prevent. IP address blocks hosting home or small business DSL addresses appear to be particularly popular for phishing attacks, presumably because thestems are often less well managed and not always up to date with current security patches, and also because the attackers are less likely to be traced than when targeting major corporate

stems. Simultaneously attacking many smaller organisations also makes incident response harder. We have observed that end users regularly access phishing content, presumably through

eiving spam messages, and a surprisingly large number appear to be at risk from becoming victims of such attacks.

ur research also suggests that phishing attacks are becoming more widespread and well organised. We have observed pre-built archives of phishing web sites targeting major online brands

ing stored, ready for deployment at short notice, suggesting the work of organised phishing groups. Such content can be further propagated very quickly through established networks of port

directors or botnets. When coupled with evidence of mass scanning and hard coded IP addresses in web content and scripts, this suggests that many instances of a particular phishing site may

active at any one time. Web traffic has been observed arriving at a newly compromised server before the uploaded phishing content was completed, and phishing spam sent from one

mpromised host does not always appear to advertise the sending host, which again suggest it is likely that distributed and parallel phishing operations are being performed by organised

oups.

ur research demonstrates a clear connection between spamming, botnets and phishing attacks, as well as the use of intermediaries to conceal financial transfers. These observations, when

mbined with quantitative data on mass vulnerability scanning and combined two-stage phishing networks, demonstrate that the threat posed by phishers is real, their activities are organised,

d the methods they employ can sometimes be quite advanced. As the stakes become higher and the potential rewards become greater, it is likely that further advancements in phishing

hniques and an increase in the number of phishing attacks will continue in the coming year. Reducing the number of vulnerable PCs contributing to botnets, countering the increasing volume ofam email, preventing organised criminal activity and educating Internet users about the potential risks from social engineering all remain significant security challenges.

summary of all the linked sub-sections of this paper that provide supporting detail can be found below:

More detailed background information about phishing

Details of UK compromise (timeline)

Details of UK compromise (content analysis)

UK attacker mole session

Analysis of UK phishing victim source IP addresses

Overview of German and UK honeynet configurations

Details of German honeypot compromise

German attacker sessions

German PHP script analysis

Analysis of German phishing victim source IP addresses

Learning about phishing from bot source code

Honeysnap sample output

uestions and comments should be directed to the German Honeynet Project and the UK Honeynet Project.

Appendix
http://www.ukhoneynet.org/http://www-i4.informatik.rwth-aachen.de/lufg/honeynethttp://www.honeynet.org/examples/honeysnap_sample1.txthttp://www.honeynet.org/breakouts/bots-code.htmlhttp://www.honeynet.org/breakouts/de-phishing-victims.htmlhttp://www.honeynet.org/details/de-honeynet_files/phishing-validation.htmlhttp://www.honeynet.org/details/de-honeynet_files/phishing-snort.htmlhttp://www.honeynet.org/details/de-detailed.htmlhttp://www.honeynet.org/details/index.htmlhttp://www.honeynet.org/breakouts/uk-phishing-victims.htmlhttp://www.honeynet.org/examples/mole.txthttp://www.honeynet.org/details/uk-analysis.htmlhttp://www.honeynet.org/details/uk-timeline.htmlhttp://www.honeynet.org/details/phishing-background.htmlhttp://www.phishreport.net/http://antiphishing.org/http://en.wikipedia.org/wiki/P2p


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dditional Informations

Background on Phishing Attacks

is side note provides further detailed background on phishing attacks, beginning with a historic overview ofphishingand social engineering, and concluding with quantitative data on phishing

empts and information on high level trends.

uring the 1990s, as the popularity and take up of the Internet grew, social engineeringwas gradually transformed and attackers began to focus on the mass consumer market. Phishers moved

m AOLto the unregulated and more anonymous Internet, with email becoming the preferred medium for engaging (often nave) end users. One reason for this change of focus might be that

line discussion forums, IRC and instant messaging were increasingly portrayed by the press as dangerous places, where evildoers and system crackers waited to ambush unsuspecting users.

so, users had become aware that legitimate companies nearly exclusively use telephone, email and traditional postal mail as means of communication with their customers, rarely participating in

s formal chat sessions. Users had also become more familiar with and confident in trusting web based authentication systems, e-shopping with credit cards, online banking services and the

otection offered by technologies such as Secure Sockets Layer (SSL)- all fronted by a myriad of different looking user interfaces.

ernet based email solutions continued to evolve at a rapid rate, with increasingly complex methods being offered to customise the look and feel of email messages and therefore potentially

oling unsuspecting users into trusting spoofed communications that might appear to be legitimate. When compared to established and relatively well policed closed loop systems, it still remains

ficult for consumers to trace the exact origin of an SMTP mail message, and the available global user base of Internet email is many times larger. Even activities with a very low success rate

n still be attractive to an attacker if the number of end users receiving the message is large enough to generate a number of responses, as can be witnessed by the continued growth in

ganisations willing to pay for the sending of spam and many users' own experiences of inboxes regularly full of unsolicited email.

a more sinister turn, phishers have not only changed their primary means of communication to email, they have also started operating in a more organised manner and to target their attacks

ainst more profitable information. In recent years, requests for AOL accounts or single credit card numbers have gradually been replaced with schemes aimed at obtaining more sensitive data,

ch as personal information that could allow unlimited access to online banking services or that could serve as a foundation to enable identity theft. Sensitive information to fraudulently

personate another persons identity might include name, date of birth, address, social security number or "secret" information such as mother's maiden name, account numbers, first school,

ts name, user names, passwords, Personal Identification Numbers (PINs) or even one-time passwords (which are quite common in European Internet banking).

e following chart that shows the top corporate phishing targets based on responses in a recent survey of spam recipients (October 2004) by email security company CipherTrust:

mage:../images/targets.PNG size=full]

ishing attacks have affected many users and have caused serious problems for some major banks. In extreme cases, some banks have been forced to shut downtheir ebanking operations for

riod of time due to phishing attacks. The exact cost to the banking industry of phishing attacks is not available in the public domain, and there are few well documented qualitative examplesof

blic arrests and prosecution (such as in Estoniaor Brazil), but it is likely to be substantial. In most cases banks will refund the money lost by their customers due to phishing attacks, although

y reserve the right not to refund such losses at their discretion. Estimates by the Association for Payment Clearing Services (APACS) for the cost of phishing attacks against UK banks were

Mfor the previous 18 months to April 2004, rising to 12Mby March 2005. Australian estimates for March 2005 were A$25M, whilst Financial Insights estimates the cost to US business

be $400Min 2004. A study by Gartner estimated the cost in 2003 to be $1.2Band the number of reported phishing attacks have massively increased since then.

October 2004 the Anti-Phishing Working Group reported that it had seen 6597 new phishing emails, an increase of 36% on the previous month. 1142 phishing web sites were reported,

uble the number for September and part of a "bumper month"during a period of huge growth in automated phishing attacks. Email filtering specialist MessageLabsreportedthat it intercepted

ore than 18 million phishing messages during 2004, and the graph below clearly shows the growth in attempted phishing attacks by email:

mage:../images/phishing-mails.PNG size=full]

e loss of trust, impact on consumer confidence and the associated financial costs of phishing attacks have become important enough for banks to set up web sites such as BankSafe Onlinetoand educate their customers, and most target brands now provide sections of their official web site with advice on identifying and avoiding online scams (such as Citizen Bank's "Online Fraud

evention Centre" or Citibank's "Learn About Spoofs" pages ). Other organisations such as the Anti Phishing Working Groupare also hoping to educate consumers as to the potential risks and

ch Internet users how to avoid online scams such as phishing attacks. However, the main challenge in preventing phishing attacks is that phishing is not a pure technology problem - the major

ntributing factor is human nature, and as long as attackers can continue to create schemes to trick unwary users, phishing will continue to be successful and potentially lucrative. As Bruce

hneier writes in a recent weblog, even issuing all end users with two-factor authentication doesn't really help to solve the problem if the phisher is successful in tricking the users into

thenticating themselves against a fake, malicious system. Given the combination of human nature, the rapid rate of technological change and the potential for illegitimate profits to be made, it

ems safe to assume that the problem of phishing will get worse before it gets better.

Detailed analysis of two phishing incidents

side note provides a more detailed overview of the two incidents discussed in the "Phishing Technique One - Phishing Through Compromised Web Servers" section of this whitepaper. One

ident was catpured using a honeypot deployed by the German Honeynet Project, and the other incident was captured by a honeypot deployed by the UK Honeynet Project.

etup and Timeline for German Honeynet Project Phishing Incident

e honeynet deployed and analysed by the German Honeynet Project in the first incident formed part of a diploma thesis ( "Planung und Realisierung eines Honeynet zur Analyse realer Angriffe

s dem Internet") by a graduate student at MAGELLAN Netzwerke GmbHin Cologne, Germany. The honeynet was a high interaction research honeynet deployed by the German Honeynet

oject during November 2004. The honeynet topology is depicted below:

mage:../images/honeynet.png size=full]

e honeynet deployed was a typical GenII honeynetbased on the three basic principles defined by the Honeynet Project: data capture, data controland data analysis.

ata capturewas performed by recording all inbound and outgoing network traffic for later analysis, using packet sniffing tools such as tethereal. All network traffic to and from a RedHat

nux honeypot was mirrored via the monitor port of a network switch and logged using the popular open source Intrusion Detection System snortrunning in binary capture mode (as daily pcap

es). To allow keystroke logging after a successful system compromise, version 2.1.7 of the Honeynet Projects Sebekkernel module was installed on the honeypot. The Redhat syslog daemon

s also modified to output syslog information to the serial port for capture by the honeynet gateway.

r data control, all network traffic from the Internet was routed through a transparent bridging honeynet gateway running the FreeBSD release 4.10 operating system that limited outgoingtwork connections from the honeypot. Outgoing connections were identified by SYN packets, differentiated and logged by TCP connection types (such as IRC-connections), and the number

connections limited to 15 IRC-connections and 10 other TCP-connections with a 24 hour period. Connection limiting is designed to allow attackers to successfully compromise the honeypot

d download a limited amount of rootkits or other malware from external servers, but to then limit their potential to attack further hosts from the compromised honeypot. It also helps to hide

presence of the honeynet gateway by not totally blocking all outbound traffic, along with preventing denial of service attacks.

r data analysis, all network traffic to or from the honeypot was mirrored to a snort IDS for pattern matching against the current signature rulebase. Manual and automated analysis of logged

a was performed regularly, along with real time monitoring and alerting.
http://honeynet.org/papers/sebek.pdfhttp://www.snort.org/http://www.ethereal.com/docs/man-pages/tethereal.1.htmlhttp://www.honeynet.org/papers/gen2/index.htmlhttp://www.magellan-net.de/http://www.magellan-net.de/honeynet/papers/thesis_sven_mueller.pdfhttp://www.honeynet.org.uk/http://www-i4.informatik.rwth-aachen.de/lufg/honeynethttp://www.schneier.com/blog/archives/2005/03/the_failure_of.htmlhttp://www.antiphishing.org/http://www.citibank.com/domain/spoof/learn.htmhttp://www.citizensbank.com/misc/prevention_center.asphttp://www.banksafeonline.org.uk/http://www.messagelabs.com/intelligence/2004report/http://www.messagelabs.com/http://news.bbc.co.uk/1/hi/technology/4037975.stmhttp://www.gartner.com/5_about/press_releases/asset_71087_11.jsphttp://www.financial-insights.com/FI/getdoc.jsp?containerId=FIN1492http://www.paymentsnews.com/2005/03/phishing_attack.htmlhttp://software.silicon.com/security/0,39024655,39128476,00.htmhttp://www.theregister.co.uk/2004/04/26/phishing_scams/http://www.apacs.org.uk/http://www.theregister.co.uk/2005/03/21/brazil_phishing_arrest/http://www.theregister.co.uk/2005/04/04/estonian_trojan_suspect_cuffed/http://www.financialcryptography.com/mt/archives/000129.htmlhttp://news.bbc.co.uk/1/hi/business/4019067.stmhttp://www.ciphertrust.com/resources/statistics/http://en.wikipedia.org/wiki/Secure_Sockets_Layerhttp://www.aol.com/http://en.wikipedia.org/wiki/Social_engineering_(computer_security)http://en.wikipedia.org/wiki/Social_engineering_(computer_security)http://en.wikipedia.org/wiki/Phishing


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e honeynet gateway was connected to a central network switch which was used to separate network traffic from the honeypot system network and the administrative network using VLANs,

ommon method to logically segmented network on the same physical hardware. The honeypot itself was a standard installation of RedHatLinux version 7.1 on Intel hardware running the

est version 2.4.20 kernel with several network services such as FTP (wu-2.6.1-16), HTTP (Apache 1.3.19, OpenSSL/0.9.6) and a database (MySQL 3.23.36) server enabled. All services

re left in their default configuration, except for the MySQL database which had a random secure password set for the root user. To make the system more realistic and more closely simulate

roduction system, a mocked up web site for an imaginary sales company was installed and reverse DNS added for the web server.

e following table depicts the timeline of the incident:

Date / Time Event

2/11/04 First data from honeypot

2/11/04

1:06 AMHoneypot WU-FTPd compromised by autorooter

2/11/04

8:21 AMAttacker manually installs rootkit, IRC bot and Ebay phishing attack content

2/11/04

6:25 PMAttacker returns to install and run mass scanning tool

2/11/04

0:40 PMAttacker returns to install proxy server

3/11/04

2:25 PMAttacker returns to install additional rootkit

3/11/04

4:40 PMAttacker returns to set up phishing web sites and sends out spam mails (blocked by Honeywall)

8/12/04

1:30 AMHoneypot disconnected for forensic analysis

more detailed incident timeline, including an analysis of the tools and techniques the attackers used, is available here.

etup and Timeline for UK Honeynet Project Phishing Incident

e honeynet deployed and analysed by the UK Honeynet Project in the second phishing incident was a high interaction research honeynet deployed in a UK ISP data centre during August

04.

mage:uk-honeynet_files/image001.jpg size=full]

e UK Honeynet deployment was similar in broad outline to the German honeynet configuration detailed above, being composed of a number of physical honeypots running default installations

common UNIX operating systems on Intel and Sparc hardware. The Honeynet Projects Honeywallbootable CDROM was used for data control, providing a transparent bridging iptables

ewall and using network connection rate limiting plus the snort-inline IPS to restrict outbound attack traffic. Another snort IDS provided data capture in binary pcap format, along with snort

d snort-inline alerting and automated daily script based data analysis.

dividual honeypots were hosted behind the Honeywall gateway, connected to an Ethernet hub, and the Honeynet project's Sebek loadable kernel module was covertly installed and enabled

each honeypot to allow full keystroke logging. All network traffic to and from the honeypots was logged in pcap format, as were any keystrokes recorded using Sebek. Any compromised

sts were eventually taken off line and imaged for later forensic examination.

e RedHat Linux 7.3 server on Intel hardware honeypot that was compromised and used to host a phishing attack was a default CDROM based installation with a number of common

twork services such as Apache and samba enabled and left un-patched.

ain, a timeline of the incident is given:

ate / Time Event

7/08/04 First data from honeypot

8/08/04

2:30 PMHoneypot samba server compromised. Various IRC tools, backdoors and mass scanners installed by multiple groups

9/08/04 Attackers check result of network scans

0/08/04 New attackers compromise honeypot

More scanning activity
http://www.honeynet.org/tools/cdromhttp://www.honeynet.org/de-detailed.htmlhttp://www.redhat.com/http://en.wikipedia.org/wiki/VLAN


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2/08/04

3/08/04

9:12 PMPhishers arrive through back door set up by initial attackers and set up phishing website

3/08/04

9:23 PMFirst web traffic arrives at web server for phishing site

7/08/04

9:30 AMHoneypot disconnected for forensic analysis

more detailed incident timeline of the UK phishing incident can be found hereand more detailed analysis, including an analysis of the tools and techniques the attackers used, can be found

re.

Details of German compromise

n November 12, 2004, the Honeynet was connected to the Internet. During the time between the start up and November 22, nothing special happened. We just observed an enormous

mber of

ckets with destination port 445 which is not critical for the installed Honeypot.

1:16 amthe Honeypot got compromised by exploitingthe WU-FTP daemon. There was no port scan or FTP connection before, the first connect was used to hack the computer which is

indication of an autorooter-tool. Such tools are used to scan whole network ranges for vulnerable machines and attack everything they come across. They just deliver their "evil" payload to

ery system in the given address range. In our case, it was probably a tool called superwusince later on, the attacker used this tool to attack further targets from the Honeypot.

til 8:21 amthere was no activity from the attacker. Probably he started the tool the night before and checked in the morning for successful gained access. As a first step he downloaded a

otkit and installed it on the Honeypot. This script-based rootkit replaces some system binaries with trojaned files:

usr/bin/dir /usr/bin/top /bin/ps

bin/ifconfig /usr/bin/slocate /usr/bin/pstree

in/netstat /usr/bin/vdir /usr/bin/socklist

usr/bin/strings /usr/bin/chattr /usr/sbin/lsof

addition, it install an SSH-daemon on port 255 which was used by the attacker to log on the Honeypot in the following. The rootkit uses source code to compile new versions of binary files.

ese trojaned executables are adjusted to the size of the original files of the target system to "hide" the presence. The rootkit also installs a sniffer to collect login information to other systems.

rthermore, it modifies the init-scripts to ensure that the installed services will start on next reboot and then sends out an information mail about the system status to the attacker. After finishing

installation, the attacker reentered the Honeypot via the additionally installed SSH service using the tool "putty", an SSH-Client for Windows-systems. Afterwards the attacker downloaded a

calledspam.tgz. This archive contains some PHP and HTML files. Further examination showed that these files contain web-pages to update the billing profile update for seller accounts of a

ge Internet auctions website. The attacker copied this files into the document root of the webserver. The "index.html" start page is a forwarding page to the auctions website. The reason for

at is that these PHP pages were incomplete. The attacker edited them, but never finished his work on this files. By tracing the IP of the attacker, the source could be located in Romania. A

an of this computer showed no open ports, so this could be the computer of the cracker.

8:49 amthe attacker downloaded another file:psybnc.tgz. After extracting the archive, he installed the included IRC-Bouncer and started an IRC-Session to an "undernet.org" server. The

annel he entered was probably used to control hacked systems. A scan of all 8 connected clients showed the same untypical open port 255 with a listening SSH-daemon like the Honeypot

d. The attacker also entered another channel and received Operator-rights there. The topic on this channel was a pointer to his personal homepage and the language used in that channel was

manian.

6:25 pmthe attacker came back and downloaded the file windmilk.tgz. This archive contains the "superwu" autorooter. After extracting the executable binary file, he started the exploiter in

creen-session with a target network as parameter. Then the attacker detached the session and logged off. Later when he came back, he attached the session again to see the results. Since the

neywall blocked all attacks, no systems could be compromised. The attacker did not realize the intervention, downloaded and installed at 10:40 pma "socksify" proxy which was configured

thout any restrictions. With this service anybody could use the Honeypot as a proxy for spreading spam or anonymous connections to any other systems. During the honeynet's online time, it

s never used.

n November 23, 2004, the attacker came back at 2:25 pm. He added the user "ro" and installed another rootkit. In a side note we present the recording of this sessioncaptured by the snort

nary logging.

4:40 pm, the attacker downloaded the archive willson.tgz. This file includes already finished webpages similar to thespam.tgzarchive. The attacker installed them in the document root

ectory of the webserver. Now this Honeypot could be used for phishing attacks. By calling the startup page, you get a login page that looks like the original login page. While unrelated to theident we report, a recent example illustrating the similarity of a phishing data entry form to compare to the acutal site can be found here.

e input of this form will be rudimentary checked with the help of a small PHP-script

m>

r both input fields (username and password), the input must be longer than one character. Note the use of the strings $mesajand $muie, which suggests a Romanian connection and have

en observed in other incidents analysed by members of the UK Honeynet Project. If the input is okay, it will be written to the file /tmp/User.doc and the next page will be shown. On this

ge, the victim is tricked into entering personal information. All input will be checked and if one is not according to the condition, an error page will be shown. This error page does not attempt

mimic the real error page and most victims would likely become suspicious of the fake web site at this point.

th the help of the following validation script, the data entered into the form is checked. The resulting page of the validation process is not interpreted by the webserver because Apache does

t accept .dllfiles as PHP files by default. The attacker forgot to set the "AddType" variable of the Apache server to interpret .dllfiles with the PHP-engine. The next activity of the

acker was downloading an archive called banksend.tgz. This file includes a PHP script for sending mails:

m>

ter downloading the test.txtfile which contained 3719 e-mail addresses, the attacker started sending phishing mails to the recipients listed in this file. The source code of this file shows the
http://www.honeynet.org/de-honeynet_files/phishing-validation.htmlhttp://www.antiphishing.org/phishing_archive/05-10-05_Paypal/05-10-05_Paypal.htmlhttp://www.honeynet.org/de-honeynet_files/phishing-snort.htmlhttp://www.securityfocus.com/bid/3581/http://www.honeynet.org/uk-analysis.htmlhttp://www.honeynet.org/uk-timeline.html


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l target of the comprised link:

ease follow the link below and renew your account information.

https://internetbanking.bank.com

this point of time we decided to block outgoing TCP ports 25 and 443 so that no victim would suffer from the phishing attacks. The attacker probably noticed that we blocked outgoing

nnections and concluded that something weird was happening. He never came back and on Decembers 8, 2004, the honeynet went offline for further analysis.

hat else did we find?

e found archives which contained pre-packaged pages for other major banks. These pages are used for gathering credit card numbers from the victims. For example, in one case the form

put will be checked with the help of JavaScript and the only condition is that the input fields are not blank. The next script sends the data to the attacker:

m>

Documents

Know Your Enemy_ Phishing