NSFOCUS Security Advisory (SA2007-01)
Microsoft IE5 CSS Parsing Memory Corruption Vulnerability
Release Date: 2007-08-15
CVE ID: CVE-2007-0943
http://www.nsfocus.com/english/homepage/research/0701.htm
Affected systems & software
===================
Internet Explorer 5.01
Unaffected systems & software
===================
Summary
=========
NSFocus Security Team discovered a memory corruption vulnerability in IE 5
that allows arbitrary code execution when parsing a malicious CSS file.
Description
============
There exists a vulnerability when IE 5.0 parses CSS due to insufficient check
on the pointer. Out-of-bound pointer reference and memory overwriting might
occur in the handling of malformed CSS files, which allows attackers to run
arbitrary code via carefully crafted data.
Attackers can run arbitrary code by crafting a malicious WEB page and alluring
users to visit it. If the victim is an administrator, then attackers can gain
complete control over the system.
The system will be vulnerable even if the security level of IE is set to
"High".
Workaround
=============
Do not visit untrusted websites.
Vendor Status
==============
2006.08.31 Informed the vendor
2006.09.01 Vendor confirmed the vulnerability
2007.08.14 Microsoft released MS07-045 to fix the vulnerability.
For more details about Microsoft Security Bulletin, please refer to:
http://www.microsoft.com/technet/security/bulletin/MS07-045.mspx
Additional Information
========================
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-0943 to this issue. This is a candidate for inclusion in the
CVE list (http://cve.mitre.org), which standardizes names for security problems.
Candidates may change significantly before they become official CVE entries.
Acknowledgment
===============
Hu Qianwei of NSFocus Security Team found the vulnerability.
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==========
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NSFocus Security Team <security@nsfocus.com>
NSFOCUS INFORMATION TECHNOLOGY CO.,LTD
(http://www.nsfocus.com)
