Zero-day vulnerability in Windows

Improper validation of array index
CVE-2010-2743

The vulnerability was discovered by Sergey Golovanov from Kaspersky Lab. The vulnerability was exploited by Stuxnet.

Known malware:

W32.Stuxnet

Vulnerability details

Advisory: SB2010101201 - Multiple privilege escalation vulnerabilities in Win32k.sys in Microsoft Windows

Vulnerable component: Windows

CVE-ID: CVE-2010-2743

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

CWE-ID: CWE-129 - Improper Validation of Array Index

Description:

The vulnerability allows a local user to execute arbitrary code with elevated privileges.

The vulnerability exists due to an error in Win32k.sys driver when handling keyboard layouts as the Windows kernel fails to validate that an array index is within the bounds of the array. A local user can load a specially crafted keyboard layout and execute arbitrary code on the target system with privileges of SYSTEM account.

Successful exploitation of this vulnerability may allow an attacker to escalate privileges on vulnerable system.

Note: this vulnerability is being actively exploited by Stuxnet.

Public Exploits:

- Microsoft Win32k - Keyboard Layout (MS10-073) [Exploit-DB]

External links:

https://technet.microsoft.com/en-us/library/security/ms10-073.aspx
https://blogs.technet.microsoft.com/srd/2010/10/12/assessing-the-risk-of-the-october-security-update...
https://securingtomorrow.mcafee.com/mcafee-labs/analyzing-the-recent-windows-zero-day-escalation-of-...
http://news.softpedia.com/news/Microsoft-Patches-One-of-Two-Stuxnet-EoP-Vulnerabilities-160840.shtml
http://link.springer.com/chapter/10.1007%2F978-3-642-35211-9_81#page-1
http://www.welivesecurity.com/2010/10/15/win32k-sys-about-the-patched-stuxnet-exploit/
https://www.beyondtrust.com/blog/microsoft-patch-tuesday-october-2010/
http://www.welivesecurity.com/2010/10/15/win32k-sys-about-the-patched-stuxnet-exploit/
http://www.welivesecurity.com/2010/10/15/stuxnet-paper-revision/

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.