NSFOCUS SA2007-01 : Microsoft IE5 CSS Parsing Memory Corruption Vulnerability


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. DISCLAIMS ========== THE INFORMATION PROVIDED IS RELEASED BY NSFOCUS "AS IS" WITHOUT WARRANTY OF ANY KIND. NSFOCUS DISCLAIMS ALL WARRANTIES, EITHER EXPRESSED OR IMPLIED, EXCEPT FOR THE WARRANTIES OF MERCHANTABILITY. IN NO EVENT SHALL NSFOCUS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF NSFOCUS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. DISTRIBUTION OR REPRODUCTION OF THE INFORMATION IS PROVIDED THAT THE ADVISORY IS NOT MODIFIED IN ANY WAY. Copyright 1999-2007 NSFOCUS. All Rights Reserved. Terms of use. NSFocus Security Team <security@nsfocus.com> NSFOCUS INFORMATION TECHNOLOGY CO.,LTD (http://www.nsfocus.com)