CVE-2004-0567

An anonymous remote attacker sends a specially-crafted network packet to TCP or UDP port 42 on a WINS server [ref_id=1]. The WINS service fails to properly validate the computer name value in the packet before copying it into a fixed-size buffer, causing an unchecked buffer overflow [ref_id=1]. On Windows NT 4.0 Server, Windows 2000 Server, and Windows Server 2003, this can allow arbitrary code execution; on Windows Server 2003, the built-in stack-based buffer overrun detection typically causes the service to crash instead, resulting in a denial of service [ref_id=1]. Firewall best practices that block port 42 at the network perimeter mitigate the attack vector [ref_id=1].

The advisory does not specify the exact function or file path. The vulnerability resides in the WINS service component that parses incoming name registration and resolution packets on TCP/UDP port 42 [ref_id=1].

The security update changes the method that WINS uses to validate the computer name value before passing it to the allocated buffer [ref_id=1]. By adding proper bounds checking on the name field, the update prevents the unchecked buffer condition that an attacker could trigger with a malicious packet [ref_id=1]. No patch diff is included in the bundle; the advisory states only that the validation logic was corrected.