Description: This security update resolves a publicly disclosed vulnerability in the Microsoft Telnet service. The vulnerability could allow an attacker to obtain credentials and then use them to log back into affected systems. The attacker would then acquire user rights on a system identical to the user rights of the logged-on user. This scenario could ultimately result in remote code execution on affected systems. An attacker who successfully exploited this vulnerability could 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 vulnerability by modifying the way that the Telnet service validates authentication replies in order to prevent the relay of credentials.

Update type: Moderate

Release date: August 11, 2009

Applies to: All versions

Knowledge base: support.microsoft.com/kb/960859

Download link: 32-bit | 64-bit

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

• Telnet Credential Reflection Vulnerability – CVE-2009-1930