There is a buffer overflow vulnerability in the Telnet service in Windows 2000 that could enable an attacker to execute arbitrary code on a vulnerable machine.
Microsoft Corp. has developed a patch for the flaw, which also affects the Telnet daemon in Microsoft Interix 2.2, the companys environment for running Unix applications on Windows machines.
Telnet, a protocol used to connect to remote machines, is installed by default in Windows 2000, but doesnt run automatically. Interixs Telnet daemon is not installed by default.
Both products have an unchecked buffer in the code that handles Telnet protocol options. If a cracker is able to perform a successful attack on the vulnerability, the Telnet service could fail and may allow the attacker to run code of his choice.
The attackers code would run in the security context of the Telnet service, which in Windows 2000 is the System context. In Interix implementations, the administrator chooses the security context manually, according to a Microsoft bulletin.
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