Some vulnerabilities have been reported in avast! Home/Professional, which can be exploited by malicious, local users to cause a DoS (Denial of Service) or gain escalated privileges.

1) A boundary error exists in the "aswMon2" kernel driver when processing IOCTLs. This can be exploited to cause a stack-based buffer overflow via a specially crafted 0xB2C80018 IOCTL.

The vulnerability is confirmed in avast! Professional version 4.8.1351. Other versions may also be affected.

2) An error in the AavmKer4.sys kernel driver can be exploited to corrupt memory via a specially crafted 0xB2D6000C or 0xB2D60034 IOCTL.

Successful exploitation of the vulnerabilities may allow execution of arbitrary code with SYSTEM privileges.

3) The application sets insecure permissions on the "DATA" directory. This can be exploited to e.g. load an arbitrary library with escalated privileges by modifying the "ISAPIFilter1" parameter in avast4.ini.

The vulnerabilities are reported in versions prior to 4.8.1356.

Solution
Update to version 4.8.1356.

Provided and/or discovered by
1) Giuseppe "Evilcry" Bonfa
2) NT Internals
3) Maxim A. Kulakov (ShineShadow)

Changelog
Further details available to Secunia VIM customers

Original Advisory
avast!:
http://www.avast.com/eng/avast-4-home_pro-revision-history.html

Giuseppe "Evilcry" Bonfa:
https://www.evilfingers.com/advisory/Advisory/Avast_aswMon2.sys_kernel_memory_corruption_and_Local_Privilege_Escalation.php

NT Internals:
http://www.ntinternals.org/ntiadv0904/ntiadv0904.html

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