A VMSF_DELTA memory corruption was discovered in unrar before 5.5.5, as used in Sophos Anti-Virus Threat Detection Engine before 3.37.2 and other products, that can lead to arbitrary code execution. An integer overflow can be caused in DataSize+CurChannel. The result is a negative value of the "DestPos" variable, which allows the attacker to write out of bounds when setting Mem[DestPos].
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
| Link | Tags |
|---|---|
| https://bugs.chromium.org/p/project-zero/issues/detail?id=1286 | third party advisory exploit |
| https://nakedsecurity.sophos.com/2012/11/05/tavis-ormandy-sophos/ | vendor advisory |
| https://security.gentoo.org/glsa/201709-24 | vendor advisory |
| https://community.sophos.com/kb/en-us/118424#six | vendor advisory |
| https://security.gentoo.org/glsa/201708-05 | vendor advisory |
| https://lock.cmpxchg8b.com/sophailv2.pdf | third party advisory |
| https://security.gentoo.org/glsa/201804-16 | vendor advisory |
| https://kc.mcafee.com/corporate/index?page=content&id=SB10205 | |
| http://telussecuritylabs.com/threats/show/TSL20121207-01 | third party advisory |
| http://securitytracker.com/id?1027725 | third party advisory |