DEEDS Meeting Oct., 26th 2006 Dependable, Embedded Systems and Software Group Department of Computer...

DEEDS Meeting Oct., 26th 2006

Dependable, Embedded Systems and Software GroupDepartment of Computer ScienceDarmstadt University of Technology

Summary of my enquiries made so far…

Daniel Germanus <daniel.germanus@gmail.com>

DEEDS Meeting Oct., 26th 2006

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Intro

•Bachelor Thesis was on Threat Modeling

•Part of Microsofts Security Development Lifecycle

•Cons can be:

– Informal method

– Static approach

•Wanted:

– New, or improved attackability measures

– Based on exact models

– Dynamic system view

– (semi) automated

!

DEEDS Meeting Oct., 26th 2006

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How to achieve?

•Enquiries on Security, Metrics, Measures and related Technologies

•Looking for Metrics, Methods and Tools

• Metrics: Attack Surface, Risk measurement

• Methods: Attack Graphs

• Tools: OPUS

• In the future: model own metrics or methods

DEEDS Meeting Oct., 26th 2006

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Attack surface (CMU)

•Definition: Sum of accessible APIs and used resources

•Non-orthogonal, three dimensional mapping:

• Targets & Enablers (i.e. resources, processes and data)

• Channels & Protocols (2 types of channels: message passing and

shared memory, every channel associated with a protocol)

• Access rights: associated with all resources

•Developed state machine model for System, Threat and User behavior

DEEDS Meeting Oct., 26th 2006

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Attack surface (CMU)

•Calculating actual attackability …

–Relative, not absolute measure

–Different approaches possible:

• Use of domain specific attack classes (cf. Threat Modeling)

• Definition of own system/channel/data attack classes

DEEDS Meeting Oct., 26th 2006

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Attack surface (CMU)

•Example for some domain specific attack classes:

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Attack surface (CMU)

•Example for actual metric application

•Using

–two different versions of an IMAP server (IMAPD1 and IMAPD2)

–own system/channel/data attack classes

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IMAPD1 .. Attack surface value is triple <3.5 , 2 , 1.66>

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IMAPD2 .. Attack surface value is triple <5 , 2 , 1.33>

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Threat Index

•Metric with cost/benefit approach

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Threat Index Visualization

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Network Attack Graphs

•Per host basis algorithms

•Supports system analysts, automated graph generation

•Input parameters are:

–a set of host nodes, H

–a set of trust relationships, T

–a set of access edges, E

–a set of network exploits, X

–a set of vulnerabilities at each host, V

–a new attacker host, h

•At this stage, only known attacks are considered

DEEDS Meeting Oct., 26th 2006

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Network Attack Graphs

DEEDS Meeting Oct., 26th 2006

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Tools

•OPUS – Online Patches and Updates for Security

–Intention: minimize downtime

–Granularity: functions (with identical signature)

• No globals,

• no nonrecurring functions (like main),

• no functions which are currently on some stack frame

–Currently only supported for C programs

–Validated with several Bugtraq incident reports for buffer overflows,

double frees, etc.

DEEDS Meeting Oct., 26th 2006

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That‘s it

Thanks.

Please, visit the DEEDS Wiki on Security related content.