Microsoft suffers DNS vulnerability attacks

Microsoft confirmed yesterday that it has uncovered targeted attacks exploiting a new vulnerability in the Windows Server DNS Service.

Microsoft immediately mobilised its Software Security Incident Response Process (SSIRP) to investigate.

Due to a stack-based buffer overrun that exists in the Windows DNS Server's remote procedure call (RPC) interface, attackers can send an RPC packet to the interface enabling them to run malicious code on the system.

This vulnerability could allow a criminal to run code in the security context of the Domain Name System Server Service in Microsoft Windows 2000 Server Service Pack 4, Windows Server 2003 Service Pack 1, and Windows Server 2003 Service Pack 2, which by default runs as Local SYSTEM.

"While the attack appears to be targeted and not widespread, we are monitoring the issue and are working with our MSRA partners to monitor and help protect customers," said Microsoft researcher Adrian Stone, in the Microsoft Security Response Centre blog

Details and workarounds can be found in Microsoft's Technet Security Advisory 935964.

Microsoft has said it is working on the problem and will provide an update through its monthly process or out-of-cycle as soon as one is available.

Users are encouraged to follow its "Protect Your PC" guidance of enabling a firewall, applying all security updates and installing anti-virus and spyware software to help minimise the possibility of a successful attack.

Microsoft is also urging customers to disable remote management over RPC capability for DNS Servers through the registry key setting, as well as block unsolicited inbound traffic on ports between 1024 and 5000 and enable advanced TCP/IP filtering, which will act as a workaround and stop attackers exploiting this vulnerability.