Description: This security update resolves one publicly disclosed vulnerability and two privately reported vulnerabilities in Microsoft Windows HTTP Services (WinHTTP). The most severe vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. The security update addresses the vulnerabilities by changing the way that Windows HTTP Services handles errors and validates certificates, and by ensuring that Windows HTTP Services correctly use NTLM credential reflection protection mechanisms.

Update type: Critical

Release date: April 14, 2009

Applies to: All versions

Knowledge base: support.microsoft.com/kb/960803

Download link: 32-bit | 64-bit

Comments:Here are the specifics on the vulnerabilities covered by this update:

• Windows HTTP Services Integer Underflow Vulnerability – CVE-2009-0086
• Windows HTTP Services Certificate Name Mismatch Vulnerability – CVE-2009-0089
• Windows HTTP Services Credential Reflection Vulnerability – CVE-2009-0550