CVE-1999-0140

Vulnerability

A denial of service vulnerability exists in Microsoft Windows NT 4.0, up to and including Service Pack 4, when the RAS/PPTP service is running. This vulnerability is triggered by sending a malformed control packet to the PPTP service's port.

Exploitation

An attacker can exploit this vulnerability by connecting to port 1723 (the PPTP/VPN service's port) on the target machine. The attacker must then send approximately 256 characters of arbitrary data, followed by a control-d character. This sequence can be initiated via a telnet session to the target machine's port 1723 [1].

Impact

Successful exploitation of this vulnerability causes the target Windows NT 4.0 machine to reboot, resulting in a denial of service for legitimate users. The attacker does not require any special privileges beyond network access to the PPTP port.

Mitigation

Microsoft Windows NT 4.0 systems are affected up to and including Service Pack 4. Information regarding a specific patch or fixed version is not available in the provided references. Users are advised to consult Microsoft for potential workarounds or updated guidance, though this system is long past its end-of-life.