Zero-day vulnerability in Windows

Privilege escalation
CVE-2009-1123

This vulnerability was used by Equation group in attacks, which involved Fanny malware. The exploit is later added to Stuxnet malware. Initially discovered by Kaspersky Lab in December 2008.

Microsoft bulletin describing 4 vulnerabilities is not clear on which vulnerability was used during the attacks. We are aware of at least two publicly disclosed exploits from this bulletin used by different malware in targeted attacks during Operation Pawn Storm and Turla.

The CVEs covered in this bulletin: CVE-2009-1123, CVE-2009-1124, CVE-2009-1125, CVE-2009-1126. At least one of them has being exploited in the wild before official security patch.

Known malware:

Exploit kits: Fanny, Stuxnet, Turla.

Vulnerability details

Advisory: SB2009060901 - Multiple priviledge escalation vulnerabilities in Microsoft Windows

Vulnerable component: Windows

CVE-ID: CVE-2009-1123

CVSSv3 score: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-822 - Untrusted Pointer Dereference

Description:

The vulnerability allows a local attacker to gain elevated privileges on the target system.

The weakness exists due to improper validation of changes in certain kernel objects. By running a malicious application, a local attacker can submit malformed calls to the Windows Kernel and execute arbitrary code in kernel mode.

Successful exploitation of the vulnerability results in privilege escalation allowing to execute arbitrary code and take complete control of an affected system.

Note: according to reports this vulnerability was being actively exploited before Microsoft issued security patch.

External links:

https://technet.microsoft.com/en-us/library/security/ms09-025.aspx
https://securelist.com/blog/research/68787/a-fanny-equation-i-am-your-father-stuxnet/
http://labs.lastline.com/unmasking-kernel-exploits

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.