Microsoft's latest security patch can cause computers running Windows XP to slow down to a crawl, users claim.
Windows XP can take up to 10 seconds to start an application after installation of the patch released last Wednesday with security bulletin MS03-013, according to users in dozens of postings to online discussion boards. The users said that removing the patch brought system speed back to normal.
Stephen Toulouse, a security program manager with Microsoft's security response centre, said Microsoft was investigating the issue.
"We have been made aware of some isolated cases of customers experiencing performance issues after applying the patch," he said. However, he added that no customers have called Microsoft's helpdesk with the problem.
The patch, which Microsoft calls the Q811493 hotfix, was distributed via Microsoft's security website and the automatic Windows Update service. It fixes a security flaw in the Windows kernel, the core of the Windows operating system. The vulnerability is rated "important" by Microsoft, one notch below the highest level on the supplier's severity rating scheme.
The flaw allows an attacker to raise his privilege level on a vulnerable system. However, to exploit the flaw an attacker needs to be able to log on to a system, either at the computer or via a terminal connection, mitigating the risk.
Microsoft is still urging all customers to apply the patch and call the Microsoft helpdesk if there are any performance issues afterward.
Microsoft security bulletin MS03-013 can be found at: