Signature validation bypass in Microsoft Windows

1) Sugnature verification bypass

EUVDB-ID: #VU4344

Risk: Critical

CVSSv4.0: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red]

CVE-ID: CVE-2013-3900

CWE-ID: CWE-310 - Cryptographic Issues

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The weakness exists due to improper validation of PE file digests during Authenticode signature verification within WinVerifyTrust function. A remote attacker can create specially crafted signed PE file, trick the victim into executing it and execute arbitrary code with privileges of the current user.

Successful exploitation of the vulnerability results in arbitrary code execution on the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Windows: Vista - 8.1

Windows Server: 2003 - 2012

CPE2.3

• cpe:2.3:o:microsoft:windows:Vista:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:XP:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:*:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:8.1:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:*:*:*:*:*:*:*:*

External links

https://technet.microsoft.com/en-us/library/security/ms13-098.aspx
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2013-3900

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.