USING EMET TO DEFEND AGAINST
TARGETED ATTACKS
PRESENTED BY
ROBERT HENSING – SENIOR CONSULTANT – MICROSOFT CORPORATION
MICHAEL MATTES – SENIOR CONSULTANT – MICROSOFT CORPORATION
WHO WE ARE
• Robert Hensing
• 15 year Microsoft employee
• TWC alum
•
5 year tour in MSRC Engineering – Defense team
• Currently Developer Consultant in National Security Group practice
• Michael Mattes
• XX year Microsoft employee
• Infrastructure consultant in NSG etc.
TRUSTWORTHY COMPUTING - SECURITY
CENTERS
Protecting Microsoft customers throughout the entire life cycle
(in development, deployment and operations)
Microsoft Security
Response Center
(MSRC)
Conception
Ecosystem Strategy
MSRC Ops
Product Life Cycle
MSRC Engineering
Microsoft Malware
Protection Center
(MMPC)
Microsoft Security
Engineering Center
(MSEC)
SDL
Security Assurance
Security Science
Release
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.
EXPLOIT ECONOMICS
Attacker
Return
=
Gains per use
X
Opportunities
to use
-
Cost to acquire
vulnerability
+
Cost to weaponize
5
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
Exploit Economics Strategy – Step 1
INCREASE ATTACKER INVESTMENT
REQUIRED TO FIND VULNERABILITIES
7
EMBEDDING SECURITY INTO SOFTWARE
AND CULTURE
Tactics for Vulnerability Reduction
Remove entire classes of vulnerabilities
•
•
Security Tooling
Additional product features
Ongoing Process Improvements
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
Exploit Economics Strategy – Step 2
PREVENT RELIABLE EXPLOITATION OF
VULNERABILITIES
EMBEDDING SECURITY INTO SOFTWARE
AND CULTURE
Tactics to Frustrate Exploits
Reduce the surface we have to defend
•
Attack surface reduction
•
Design additional product mitigations
Ongoing Process Improvements
Make remaining vulnerabilities difficult or impossible to exploit
•
Build mitigations that add exploit brittleness
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
11
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)
12
MEMORY SAFETY MITIGATIONS ROADMAP
/GS 1.0 /GS 1.1
Stack
/GS 2.0 EH4
Heap / Pool
Heap 1.0
Executable
Code
DEP
SEHOP
Heap 2.0
/GS 3.0
HeapTerm
/NXCOMPAT
Safe
Unlinking
ASLR
DEP+ATL
DEP IE8
SEHOP
IE9
DEP O14
2003
2004
2005
2006
2007
2008
2009
2010 2011
13
ENHANCED MITIGATION EXPERIENCE TOOLKIT
(EMET)



EVOLUTION OF EMET MITIGATIONS
MS12-037 – INTERNET EXPLORER CVE-2012-1875
(SAME ID)
• 0-day vulnerability being used in limited targeted attacks prior to
bulletin release.
• 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 MS12-037 - http://technet.microsoft.com/enus/security/bulletin/ms12-037
• Standard mitigations in the bulletin were
• Don’t open Office documents
• Killbit the AX control in IE
EMET VS. MS12-037 - CVE-2012-1875 (SAME ID)
CALL TO ACTION
• Follow the Security Research and Defense blog
http://blogs.technet.com/b/srd/
• Evaluate and Deploy EMET v3.5 or newer
• 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
DEPLOYMENT AND MANAGEMENT VIA GROUP
POLICY