Detailed exploit code for a Windows XP security vulnerability has been published on the Internet, offering a roadmap for hackers to disable the firewall embedded in the operating system. Microsoft on Oct. 31 confirmed it is investigating the issue, which targets ICS (Internet Connection Sharing), a feature in Windows XP that lets users share a dial-up or broadband connection with other users on a home network.

Security alerts aggregator Secunia rates the bug as "less critical" and recommends that Windows XP users find an alternative way to share the Internet connection. The vulnerability is caused due to a NULL pointer dereference error in Windows NAT Helper Components (ipnathlp.dll) and can be exploited to crash the service via a specially crafted DNS query.