[tor-bugs] #13893 [Tor Browser]: Torbrowser 4.0.X crashes on start when using MS EMET 5.1
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Sun Dec 7 20:31:56 UTC 2014
#13893: Torbrowser 4.0.X crashes on start when using MS EMET 5.1
-----------------------------+----------------------
Reporter: Diapolo | Owner: tbb-team
Type: defect | Status: new
Priority: major | Milestone:
Component: Tor Browser | Version:
Resolution: | Keywords: EMET
Actual Points: | Parent ID:
Points: |
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Comment (by Diapolo):
The default protection profile for firefox.exe (which is also used for the
Tor Browser) is this here:
<AppConfig Path="*" Executable="firefox.exe">
<Mitigation Name="DEP" Enabled="true" />
<Mitigation Name="SEHOP" Enabled="true" />
<Mitigation Name="NullPage" Enabled="true" />
<Mitigation Name="HeapSpray" Enabled="true" />
<Mitigation Name="EAF" Enabled="true" />
<Mitigation Name="EAF+" Enabled="true">
<eaf_modules>mozjs.dll;xul.dll</eaf_modules>
</Mitigation>
<Mitigation Name="MandatoryASLR" Enabled="true" />
<Mitigation Name="BottomUpASLR" Enabled="true" />
<Mitigation Name="LoadLib" Enabled="true" />
<Mitigation Name="MemProt" Enabled="true" />
<Mitigation Name="Caller" Enabled="true" />
<Mitigation Name="SimExecFlow" Enabled="true" />
<Mitigation Name="StackPivot" Enabled="true" />
<Mitigation Name="ASR" Enabled="false" />
</AppConfig>
This lists the SimExecFlow mitigation technique, which is one from
different ROP (return oriented programming) techniques in EMET, which
Microsoft describes as: "Without EMET in place, attackers can take
advantage of a predictable mapping of those dlls and could use them in
order to bypass DEP through a known technique called return oriented
programming (ROP)."
Some details are listed here:
http://blogs.technet.com/b/srd/archive/2012/07/24/emet-3-5-tech-preview-
leverages-security-mitigations-from-the-bluehat-prize.aspx
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13893#comment:6>
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