Upping the ‘Anti’: Using Memory Analysis to Fight Malware4tphi.net/fatkit/papers/Walters_2008_SANS.pdfEM POWER INGINVESTIGATORS VOLATILE SYSTEMS Upping the ‘Anti’: Using Memory

EMPOWERING INVESTIGATORS

VOLATILE SYSTEMS

Upping the ‘Anti’:

Using Memory Analysis to Fight Malware

SANS Incident Response and Forensics Summit

October 13, 2008

AAron Walters

2 VVVV LATILESYSTEMS

About Volatile Systems

• We provide the solutions and knowledge to address volatile memory analysis needs:• Software customizations, integrity assessments, incident response, malware analysis, training

• Proven technology• 5 yrs of published university research • Technology licensed (commercial, government, etc)• Volatility (contributors: experts/organizations) • LEO/investigators worldwide

• Field experienced analysts• Focused on volatile memory analysis (5 yrs)• Universities, government, military, LE, commercial• Thousands of memory images/malware

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State of Malware

• Volume of new malware increasing (2007)– Symantec: 2/3 of malware (711,912)– F-Secure: 1/2 of malware (20 yrs)

• A/V detection ineffective (Bailey, 2007)

– 6 weeks worth of malware/ 5 A/V vendors

– 1 month later → 56% detected

– ~6 months later → 66% detected

Malware Detected by Year(Source: Security Fix)

010000002000000

3000000

40000005000000

6000000

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

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Malware Trends

• Targeted Attacks• Financially/politically motivated• Zero-day vulnerabilities (documents)

• Proliferation of stealth technology (memory)• Kernel rootkits (Storm)• Code injection (DLLs, etc)

• Commercialization of malware• Quality assurance• Performance guarantees

• Evolving malware• Refining methods → successes/failures• Tactics escalation

• Upping the “Anti”• Anti-detection, Anti-debugging, Anti-forensics


Incidents: Defense Industry

• Attacks• Government contractors• Upper management• Sophisticated spear phishing

• Agent• Undetected (AV/anti-rootkit)• Quickly evolving variants (weeks)• Small system footprint

• Command and Control• Messages: steganography/encoded• Channel: protocols/ports/servers

• Lay dormant ......

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Incidents: Financial Industry

• Attacks• Targeting online money

• Bank accounts, online payment, CCNs

• Multi-platform (Windows, Linux)

• Clients• Undetected (AV/anti-rootkits)

• Stealth technology (i.e. rootkits, packers)

• Exfiltrating data• Usernames, passwords, etc (browser)• Process memory (i.e. Canvas)

• Servers• Hijacking servers

• User-mode rootkits (i.e. code injection)

• Hiding artifacts in memory

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Now what?

• Detection is just the beginning!

• Actionable data

• Identify other systems involved (triage)• Determine how they gained entry• Elucidate intent• Evaluate capabilities• Assess damage• Quantify current state/measure improvement

• Across the enterprise!

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Opaque Enterprise

• Opaque components of information infrastructure• What is running? (patches,malware,etc)


Consistent Picture

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Digital Crime Scene


Runtime State

• Order of Volatility (RFC 3227)• Data life expectancy

• Volatile state/active objects

• Ceases to exist when power is removed

• Valuable data (context)

• Volatile media “trusted” (pswds, keys, malware)

• Goals (Carrier, 2003):

• Minimize obtrusiveness

• Minimize trust

• Understand effects


Live Response

• Quickly collect information from live machine

• Response tookits & agents

• Antivirus/rootkit detectors

• SysAdmin tools (WFT,COFEE) /APIs (Guidance)

• Limitations

• Depend on OS (trust, information)

• Obtrusive (substantial and complex: >30% (Walters,2007))

• Unverifiable (3rd Party)

• Unable to clarify or expand (pigeon holed)

• Best evidence? (relative)


Volatile Memory Analysis

• Entire contents of physical memory (RAM)

• Direct analysis of raw bit “image”

• Artifact persistence/unallocated memory (Chow,2005)

• Advantages:

• Analysis does not depend on OS (trust)

• Reduce and simplify obtrusiveness (acquisition)

• Removes the active adversary (freeze state)

• Verifiable (3rd Party: data and tools)

• Unconstrained analysis (raw data)

• Challenges

• Acquisition/Temporal proximity

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In the beginning…..

• Old school memory analysis• dd, crash dumps, kcores, swap• Printable character sequences• strings, less, grep, hexedit, text editor

• Investigative leads• Passwords, email addresses, IP addresses, commands, domain names, file names, URLs

• Large quantity of data• 2GB Memory → 818MB

• Context free data• Spatial proximity (paging, unallocated, etc)• 259621376:Netcat network data redirector.• 259621376 [2936:412200 ] Netcat network data redirector.


Memory Analysis Types

Physical Memory Analysis

Virtual Memory Analysis

Application Analysis

Physical Address Space

Kernel Address Space

Application Address Space

User Address Space

Swap

Context


VOLATILITY

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Volatility

• Volatile memory forensics framework• Completely open source (Python)• Cross platform analysis: Windows, Linux

• No MS DLLs! (Windows, Linux, OS X, etc)• 32-bit XP SP2/SP3* (PAE/NOPAE)

• Extendable to other hardware/operating systems

• Command-line tools• Places you can find Volatility

• PyFlag, DFlabs PTK, VolShell, PlainSight, SIFT, Helix

• Powerful modular architecture!• Practitioners, trainers, researchers


Community: Order of Volatility

• Code Contributers:• Michael Cohen• David Collett

• Brendan Dolan-Gavitt

• Blake Matheny

• Andreas Schuster

• Research Collaborators:

• Jide Abu

• Jose Nazario

• Doug White

• Matthieu Suiche

• Testing/Bugs:

• Joseph Ayo Akinyele

• Testing/Bugs (Cont)

• Tommaso Assandri

• Harlan Carvey

• Eoghan Casey

• Jim Clausing

• Jon Evans

• Robert Guess

• Jesse Kornblum

• Jamie Levy

• Eugene Libster

• Erik Ligda

• Tony Martin

• Golden G. Richard III

• Sam F. Stover

Credits

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Volatility

• Types of information (live response)• Running processes• Strings to process mappings• Open network connections• Process to files (DLLs)• Process to port mappings• System time

• Techniques• Data structure traversal (list walking, table crawling, tree climbing)

• Fixed offsets (symbols)• Linear scanning

• Object oriented scanning framework (Schuster, Cohen)

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Volatility 1.3: Highlights

• Data view modules ( > 13 new modules!)• raw2dmp• rejobjkeys• procdump

• Dynamic plugin support• VolShell (Dolan-Gavitt)• ssdt (Dolan-Gavitt), getsids (Dolan-Gavitt)• 11 Linux modules

• Address Spaces• PrivacyPreservingAddressSpace (experimental)

• Only stores necessary data

• WindowsCrashDumpSpace32 (Schuster)

• Microsoft’s crash dump format (full dumps)

• HiberfilSpace32 (Suiche, Dolan-Gavitt)

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Volatility 1.3: Hibernation File

• Microsoft’s hibernation file format (hiberfil.sys)• SandMan project (Matthieu Suiche)

• http://sandman.msuiche.net

• Microsoft Interoperability Initiative• [MS-DRSR] DecompressWin2k3()

• Compressed chunks of physical memory (Xpress)• xpress.py (Dolan-Gavitt)

• Maps physical address to decompressed offset

• Limitations

PrivacyAddrSpaceStore

HiberfilSpace32

IA32PagedMemoryPae

FileAddressSpace

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Integrating Memory

• DFRWS 2008 Forensics Challenge• Evidence fusion: memory, hard disk, network• PyFlag/Volatility (Cohen, Collet, Walters)

• Role of memory forensics• Carving memory image

• Exfiltration script• Encryption keys

• SSL decryption• Volatile targeting

• Network traffic/open files• Attribution

• User activity (strings)• Temporal information

• Time zone/timestamps


Temporal Reconstruction

• It’s about time…… (timeline)

• "the most potentially valuable forensic tool in your digital detective toolkit" (Farmer,2000)

• Temporal relationships between artifacts

• Volatile Time: absolute vs. relative

• Temporally link disparate events

• Visualization• Presentation

• Instantaneous events, duration events• Knowledge discovery


Temporal Reconstruction

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Component Age Diagrams

• Visualize anomalies in component timestamps (Vostokov, 2008)

12/6/1999

4/19/2001

9/1/2002

1/14/2004

5/28/2005

10/10/2006

2/22/2008

Modules

Date


Integrity Matters

• Evaluate the runtime state of machine (audit)• Trusted, suspicious, compromised

• Deriving trust (Petroni, 2008)• Immutability (roots of trust)

• Kernel/user text (executable instructions)• Control flow integrity

• Static function tables (IDT,SSDT,IAT, etc.)• Dynamic data structures (heap, stack, etc.)

• Semantic integrity • Semantic relationships in dynamic data• Policy enforcement (ports, registry, exe versions, etc)

• Statistics/clustering• Measured integrity• Cluster machines


Deriving Trust: Stack

0x22c000

sp

0xb0618a

0xb000000x22c844

0x230000

0x22c6e4 0xb00000

0x22c83c

0x22ca1c

0x10000000

0x10000000

ext783937.dll

metsrv.dll

24

22metsrv.dll

ext783937.dll

0xb00000


Delta Detective™

• Automated malware analysis (real systems)• State changes in memory (semantic model)

• Objects (committed/free)• Data structures (i.e., VAD Tree, Loaded DLLs)• Control flow changes (hooking, text changes)

• Semantic Diff™• Persistant changes to volatile storage• Automatically generate a malware profile

• Malware library (global collection)• Volatile Intelligence Network• Crawling, spam traps, honeypots (updated daily)• Threat reports/profiles


Automated Malware Analysis

Malware Database

Report Database

Malware Cluster

Delta Detective

Malware Installed

Acquire RAM + Swap

Acquire RAM + Swap


Objects: Set Difference

After \ Before = { x : x∈∈∈∈After and x∉∉∉∉Before}


Data Structures (VAD)


Control Flow Changes


Extracting Malware

Header

reloc

text

idata

Header Header

edata

▲▲

▲ ▲▲

▲

Disk Memory Extract

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2.03Extend Your Arsenal

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What is F-Response?

• F-Response is a small, largely self contained application that provides read-only,authenticated network access to a remote computer’s Physical Disk and Physical Memory.

• Minimal system impact (obtrusiveness)

• F-Response 1.18 (Physical Disk Only)

• Windows (2000, XP, 2003, Vista, 2008)

• Linux, OS X Intel (10.4. 10.5)

• F-Response 2.03 (Physical Disk + Physical Memory) - Beta

• Windows (2000, XP, 2003, Vista, 2008)

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How does F-Response work?

• F-Response is based on the well documented

iSCSI standard to create a secure, read-only

connection between the examiner’s computer

and the computer under inspection.

• F-Response makes the storage devices and

physical memory on the computer under

examination completely accessible to the

examiner’s computer where they appear as

local, raw, physical storage devices.

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F-Response in Deployment

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F-Response & Volatility

• Joint project between F-Response and

Volatility to extend the framework with

real-time remote access capability.

• Months of development and testing.

• Both products will continue to work

separately, however the two combined

give you....

VOLTAGE

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Voltage

• Real-time read-only access to runtime state• Physical memory• pagefile.sys

• Combine detection with response • Temporal proximity• Acquisition capabilities

• Continuous independent monitoring• Visibility into the enterprise• Verify the state of systems


Voltage Demo


Conclusions

• Volatile state is a critical component of the digital crime scene

• Memory analysis “Ups the Anti”

• Columbia Pictures et al. v. Justin Bunneli

• RAM is Electronically Stored Information

according to the Federal Rules of Evidence

Download Volatility 1.3http://www.volatilesystems.com/

Join the community!

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For more information

• Web: http://www.f-response.com

• Email: [email protected]

• Phone: 1-800-317-5497


Questions?

Feedback, questions, comments...awalters [at] volatilesystems [dot] com


Resources

• Acquisition• Open source:

• mdd: https://sourceforge.net/projects/mdd/• win32dd: http://win32dd.msuiche.net/

• Commercial• F-Response 2.0: http://www.f-response.com/• Kntdd: http://gmgsystemsinc.com/knttools/

• Conferences• Open Memory Forensics Workshop (OMFW)• Digital Forensics Research Workshop (DFRWS)

• Mailing Lists• www.volatilesystems.com/mailman/listinfo

• Research References• www.4tphi.net/fatkit


Resources (Cont.)

• Blogs• http://volatility.tumblr.com/• http://volatilesystems.blogspot.com/• http://moyix.blogspot.com• http://computer.forensikblog.de/en/• http://windowsir.blogspot.com/• http://jessekornblum.livejournal.com/

• Books• Malware Forensics (Aquilina, Casey, and Malin)• Windows Forensic Analysis (Harlan Carvey)• Forensic Discovery (Farmer and Venema)

Documents

Upping the ‘Anti’: Using Memory Analysis to Fight Malware4tphi.net/fatkit/papers/Walters_2008_SANS.pdfEM POWER INGINVESTIGATORS VOLATILE SYSTEMS Upping the ‘Anti’: Using Memory