Avast Integer Overflow Verifying numFonts in TTC Header

2015-12-10 23:05:25

Source: https://code.google.com/p/google-security-research/issues/detail?id=549

If the numFonts field in the TTC header is greater than (SIZE_MAX+1) / 4, an integer overflow occurs in filevirus_ttf() when calling CSafeGenFile::SafeLockBuffer.

The TTC file format is described here https://www.microsoft.com/typography/otspec/otff.htm

Proof of Concept:
https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/38934.zip

Fixes

No fixes

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