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Using EMET to defend against targeted attacks

Using EMET to defend against targeted attacks. Presented by Robert Hensing – Senior consultant – Microsoft Corporation. WHOAMI. Robert Hensing 15 year Microsoft veteran

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Using EMET to defend against targeted attacks

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  1. Using EMET to defend against targeted attacks Presented by Robert Hensing – Senior consultant – Microsoft Corporation

  2. WHOAMI • Robert Hensing • 15 year Microsoft veteran • Developed original versions of W.O.L.F. and AutoDump+ (tools used by Customer Support for Incident Response and Debugging respectively) • Trustworthy Computing Division alumni • 5 year tour in MSRC Engineering – Defense team • Co-Developed GUT (swiss army knife hex editor / fuzzer / vulnerability detection framework) • Co-Developed a technique that uses the Windows shim engine to mitigate vulnerable code via ‘Shimpatches’ (as featured in recent IE Security Advisories) • Currently a boring C# Developer Consultant in National Security Group practice • I used to be somebody. 

  3. Trustworthy Computing - Security Centers Protecting Microsoft customers throughout the entire life cycle (in development, deployment and operations) Conception Conception Microsoft Security Response Center (MSRC) Microsoft Security Engineering Center (MSEC) Ecosystem Strategy Product Life Cycle Product Life Cycle MSRC Ops SDL MSRC Engineering Security Assurance Security Science Release Release Microsoft Malware Protection Center (MMPC)

  4. The software vulnerability asymmetry problem Defender must fix all vulnerabilities in all software – attacker wins by finding and exploiting just one vulnerability Threats change over time – state-of-the-art in vulnerability finding and attack techniques changes over time Patch deployment takes time – vendor must offset risks to stability & compatibility, customer waits for servicing cycle Result: Attackers only have to find one vulnerability, and they get to use it for a really long time.

  5. Exploit Economics Gains per use X Opportunities to use Cost to acquire vulnerability + Cost to weaponize Attacker Return = -

  6. Exploit Economics We can decrease Attacker Return if we are able to… Increase attacker investment required to find usable vulnerabilities • Remove entire classes of vulnerabilities where possible • Focus on automation to scale human efforts Increase attacker investment required to write reliable exploits • Build mitigations that add brittleness • Make exploits impossible to write completely reliably Decrease attacker’s opportunity to recover their investment • Shrink window of vulnerability • Fewer opportunities via artificial diversity • Enable rapid detection & suppression of exploit usage Desired Result: Usable attacks will be rare and require significant engineering; working exploits will become scarce and valuable

  7. Exploit Economics Strategy – Step 1 Increase attacker investment required to find vulnerabilities

  8. Embedding security into software and culture • Tactics for Vulnerability Reduction • Remove entire classes of vulnerabilities • Security Tooling • Additional product features • Remove all currently findable vulnerabilities • Complete automation of tooling • SDL tools, Threat Modeling tool • Fuzzing toolsets + ways to streamline & improve triage • Tool overlays to increase signal-to-noise and focus attention on the right code • Verification & enforcement • Audit individual tool usage via process tools • Process tools required for SDL signoff - policy enforcement Ongoing Process Improvements

  9. Exploit Economics Strategy – Step 2 PREVENT RELIABLE EXPLOITATION OF vulnerabilities

  10. Embedding security into software and culture • Tactics to Frustrate Exploits • Reduce the surface we have to defend • Attack surface reduction • Design additional product mitigations • Make remaining vulnerabilities difficult or impossible to exploit • Build mitigations that add exploit brittleness Ongoing Process Improvements

  11. Digital Countermeasures • Improve system survivability against exploitation of unknown vulnerabilities • Three goals: • Increase attacker requirements – e.g. must be authenticated, local subnet only • Deterrent – no economically reliable exploit exists • Mitigation – Break 100% reliable universal exploits • Often must be combined together • Even when successful, the result is still impactful to the user

  12. Mitigation Approaches Utilize Knowledge Deficits • Utilize secrets such that guessing impairs exploit reliability • /GS: Protect stack buffers by checking random cookies placed between them and control structures • Function Pointer Encoding Artificial Diversity ASLR: Address Space Layout Randomization Enforce Invariants • Data Execute Protection (DEP) • Heap & pool metadata checks • SafeSEH / SEH Overwrite Protection (SEHOP)

  13. Memory Safety Mitigations Roadmap Stack /GS 1.0 /GS 1.1 /GS 2.0 EH4 SEHOP /GS 3.0 Heap Rand / Hardening Heap / Pool Heap 1.0 Heap 2.0 HeapTerm Safe Unlinking SEHOP + HEASLR + ForceASLR IE10 Executable Code SEHOP IE9 DEP /NXCOMPAT ASLR DEP+ATL DEP IE8 DEP O14 2008 2009 2010 2003 2005 2006 2007 2004 2012 2013 2011

  14. Software security has evolved Windows XP SP3 Internet Explorer 8 Windows 8Internet Explorer 10 • Mitigations in software have evolved significantly since the release of Windows XP • Internet Explorer 10 on Windows 8 benefits from an extensive number of platform security improvements (not available to Internet Explorer 8 on Windows XP) No Yes SEHOP No Yes Protected Mode Enhanced Protected Mode (EPM) No Yes No Yes Virtual Table Guard Limited Extensive ASLR No Yes Stack randomization Heap randomization Yes No Yes No Image randomization Yes No Force image randomization Yes No Bottom-up randomization Top-down randomization No Yes Yes No High entropy randomization Yes No PEB/TEB randomization Extensive Limited Heap hardening Yes No Header encoding Yes No Terminate on corruption Yes No Guard Pages Yes No Allocation randomization Yes Yes Safe unlinking Yes Yes Header checksums Yes Yes /GS Yes No Enhanced/GS Yes Yes SafeSEH

  15. Enhanced Mitigation Experience Toolkit (EMET) • Offers security mitigations for most software • Old applications • Third party software • Line of business applications • Brings newer security mitigations to older platforms • Provides exclusive state of the art security mitigations to block current exploit techniques • Download the latest bits:http://www.microsoft.com/emet • EMET 4.1 supported on Windows XP • EMET 5.0 and later require Vista or higher

  16. Evolution of Emet mitigations & FEATURES • Mitigations in v2.0 • Mandatory ASLR • EAT Access Filtering • Heap Spray Allocation Mitigations in v1.0 • Dynamic DEP • SEHOP • NULL Page protection • Features added in v3.0 • 3 Protection Profiles • ADMX Files for Group Policy Management • EMET Notifier(alerts user when mitigations were enforced) • Mitigations in v3.5 • Anti-ROP mitigations: • Caller Checks • Exec Flow Simulation • Stack Pivot Mitigation • Load Library Checks • Memory Protection Checks

  17. EVOLUTION OF EMET MITIATIONS (CONTINUED) • Mitigations & Features in v4.1 • Updates to default protection profiles • Improved Event Logging • App-Compat updates / fixes • Fix to allow shared remote desktops • Mitigations & Features in v4.0 • Certificate Pinning • Early Warning Program (telemetry via Microsoft Error Reporting) • Could be used to find 733t 0-day! • Blocks known bypasses (deep hooks) • Updated rules to fix app-compat issues • Audit Mode (i.e. No Kill Mode) • Configuration Wizard • Mitigations & Features in v5.0 (Vista+) • Attack Surface Reduction • Preventing unwanted 3rd party modules from loading in applications • EAF+ • Adds KernelBase to protected functions • Adds additional checks to existing protected exports

  18. MS13-008 – Internet explorer CVE-2012-4792 (Cbutton Use After free) • 0-day vulnerability being used in limited targeted attacks prior to bulletin release discovered by FireEye circa 12/27/2012 • Vulnerability about as bad as it gets! • Remote Code Exec vulnerability in all versions of IE (at the time) and exploitable via a web page • Fixed by MS13-008 on 1/14/2013http://technet.microsoft.com/en-us/security/bulletin/ms13-008 • Standard mitigations in the bulletin were • Don’t open Office documents • Set Internet zone to High (yeah right) • Disable Active Scripting and ActiveX controls (yeah right)

  19. Demonstration - EMET vs. MS13-008CVE-2012-4792 (cButton UAF) A ‘watering hole’ attack from www.issa-balt.org

  20. demonstration

  21. RECENT EMET RELATED DEVELOPMENTS • ATTACKERS VS. EMET IN THE NEWS • February 11th • SECURITY COMPANY VS. EMET IN THE NEWS • February 24th • MICROSOFT VS. EMET IN THE NEWS • February 25th

  22. This exploit attempt will self-destruct . . .

  23. THIS AIN’T A SCENE IT’S A @#$% ARMS RACE • On February 24thBromium Labs claimed to be able to bypass all EMET 4.1 mitigations leading to a big press cycle during the RSA conference • They discussed ways of bypassing the various ROP mitigations individually, and a way of bypassing the StackPivot mitigation. • They created an exploit payload that made use of many of their discoveries but that eventually needed to call NtProtectVirtualMemory (an API that is only protected when ‘Deep Hooks’ is enabled) • They noted Deep Hooks was not enabled by default so this was convenient for them. • So EMET 5.0 will enable Deep Hooks by default!  • This required working with some vendors (McAfee HIPS) to wait for updated versions of their products to be released. • Bottom Line – EMET is not invincible but it does raise the bar for adversaries and Microsoft is committed to investigating new bypasses and addressing them in future versions of EMET if possible.

  24. OH NOZ!!! THE END IS NEAR! (0-DAY May) • On April 8, 2014, Windows XP will no longer be supported by Microsoft. This means customers will no longer receive: New security updates Non-security hotfixes Free or paid assisted support options Online technical content updates • New vulnerabilities discovered after support ends for Windows XP will not be addressed without an expensive custom support agreement • If only there was something inexpensive that you could do to protect all those un-patched Windows XP boxes from exploit attempts. 

  25. Call to action • Follow the Security Research and Defense blog to stay on stop of the latest trends in security research and defense! • http://blogs.technet.com/b/srd/ • Keep an eye on www.microsoft.com/emet for updates and announcements • Evaluate and Deploy EMET 4.1 (XP+) now or EMET 5.0 (Vista+) when it releases. • Protect critical applications such as Internet Explorer, Firefox, Office, Adobe Acrobat etc • Monitor for EMET related events in the event log using System Center or other Enterprise monitoring software to spot 733t 0-day attempts (that don’t detect EMET and self-destruct! ) • Support: http://social.technet.microsoft.com/Forums/security/en-US/home?forum=emet

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