CVE-2014-1776

Use-after-free vulnerability in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to the CMarkup::IsConnectedToPrimaryMarkup function, as exploited in the wild in April 2014. NOTE: this issue originally emphasized VGX.DLL, but Microsoft clarified that VGX.DLL does not contain the vulnerable code leveraged in this exploit. Disabling VGX.DLL is an exploit-specific workaround that provides an immediate, effective workaround to help block known attacks.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• http://blogs.technet.com/b/srd/archive/2014/04/30/protection-strategies-for-the-security-advisory-2963983-ie-0day.aspx
• http://secunia.com/advisories/57908
• http://securitytracker.com/id?1030154
• http://www.fireeye.com/blog/uncategorized/2014/04/new-zero-day-exploit-targeting-internet-explorer-versions-9-through-11-identified-in-targeted-attacks.html
• http://www.kb.cert.org/vuls/id/222929
• http://www.osvdb.org/106311
• http://www.securityfocus.com/bid/67075
• http://www.signalsec.com/cve-2014-1776-ie-0day-analysis/
• https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-021
• https://technet.microsoft.com/library/security/2963983
• http://blogs.technet.com/b/srd/archive/2014/04/30/protection-strategies-for-the-security-advisory-2963983-ie-0day.aspx
• http://secunia.com/advisories/57908
• http://securitytracker.com/id?1030154
• http://www.fireeye.com/blog/uncategorized/2014/04/new-zero-day-exploit-targeting-internet-explorer-versions-9-through-11-identified-in-targeted-attacks.html
• http://www.kb.cert.org/vuls/id/222929
• http://www.osvdb.org/106311
• http://www.securityfocus.com/bid/67075
• http://www.signalsec.com/cve-2014-1776-ie-0day-analysis/
• https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-021
• https://technet.microsoft.com/library/security/2963983
• https://www.vicarius.io/vsociety/posts/cve-2014-1776-use-after-free-vulnerability-in-microsoft-internet-explorer-detection-script
• https://www.vicarius.io/vsociety/posts/cve-2014-1776-use-after-free-vulnerability-in-microsoft-internet-explorer-mitigation-scripts