Secunia

Multiple vulnerabilities have been reported in Microsoft Internet Explorer, which can be exploited by malicious people to conduct cross-site scripting attacks or compromise a user's system.

1) A use-after-free error during event handling when the object firing the event is removed from the markup can be exploited to corrupt memory.

NOTE: This vulnerability is currently being actively exploited.

2) An error in the Internet Explorer 8 XSS filter may cause an HTML attribute to be incorrectly disabled in otherwise properly filtered HTTP response data. This can be exploited to bypass the filter and execute arbitrary HTML and script code in the wrong security context.

3) An error when validating input parameters in URLs may result in execution of a program on the local system.

4) An error exists in the handling of "Col" elements used within an HTML table container, which may result in memory corruption.

5) A use-after-free error exists in the handling of elements that manipulate the font baseline (e.g. "sub" or "sup") when rendering intertwined "strike" and "center" tags.

6) A use-after-free error exists in the handling elements used within a table container.

7) An error in the "mergeAttributes()" method when accessing an object that has not been initialised or has been deleted may result in memory corruption.

8) A use-after-free error in the handling of cloned DOM objects in Javascript can be exploited via a specially crafted sequence of object cloning.

Solution
Apply patches.
Further details available in Customer Area

Provided and/or discovered by
1) Reported as a 0-day.
The vendor also credits Meron Sellem, BugSec.
2) The vendor credits David Lindsay "thornmaker" and Eduardo A. Vela Nava "sirdarckcat".
3) Lostmon Lords.
Brett Moore of Insomnia Security, reported via ZDI.
4) wushi, team509 via Zero Day Initiative.
5, 6) Sam Thomas, eshu.co.uk via Zero Day Initiative.
7) Haifei Li, Fortinet's FortiGuard Labs.
8) Peter Vreugdenhil, Verisign iDefense Labs via Zero Day Initiative.

Changelog
Further details available in Customer Area

Original Advisory
Microsoft (KB979352):
http://www.microsoft.com/technet/security/advisory/979352.mspx
http://blogs.technet.com/msrc/archive/2010/01/14/security-advisory-979352.aspx

MS10-002 (KB978207):
http://www.microsoft.com/technet/security/Bulletin/MS10-002.mspx

ZDI:
http://www.zerodayinitiative.com/advisories/ZDI-10-011/
http://www.zerodayinitiative.com/advisories/ZDI-10-012/
http://www.zerodayinitiative.com/advisories/ZDI-10-013/
http://www.zerodayinitiative.com/advisories/ZDI-10-014/

Lostmon Lords:
http://lostmon.blogspot.com/2010/01/internet-explorer-6-7-8-url-validation.html
http://lostmon.blogspot.com/2010/02/internet-explorer-7-8-url-validation.html

Fortinet:
http://www.fortiguard.com/advisory/FGA-2010-05.html

Insomnia Security:
http://www.insomniasec.com/advisories/ISVA-100216.1.htm

Other references
Further details available in Customer Area

Technical Analysis
Further details available in Customer Area

Alternate/detailed remediation
Further details available in Customer Area

Deep Links
Links available in Customer Area