Microsoft is revising a security patch for Windows XP systems with Service Pack 1 installed after customers complained that installing the patch slowed their systems down.
Microsoft is working on a revised patch for Windows XP Service Pack 1 and will re-issue that patch when it has been completed and fully tested, the software maker said in a revised version of its security bulletin MS03-013.
Originally released on 16 April, the security bulletin addressed a buffer over-run vulnerability in the Windows kernel, which manages core services for the operating system such as allocating processor time and memory, as well as error handling.
A flaw in the way the kernel passes error messages to a debugger could enable a malicious hacker to take any action on a vulnerable system such as deleting data, reconfiguring the device or modifying user accounts and privileges, Microsoft said.
Soon after the patch was released, however, Windows XP users began complaining in online forums of performance problems that appeared after the patch was applied.
Users reported that Windows XP can take up to 10 seconds or even more to start an application after installation of the patch. Removing the patch brings system speed back to normal, Windows XP users wrote in dozens of postings on several online discussion boards.
The company received a "small number" of complaints resulting from "special situations" involving the interaction of XP Service Pack 1 and third-party applications following the patch, according to Stephen Toulouse, security programme manager at Microsoft's Security Response Centre.
Microsoft has lowered the Windows Update ranking for the security patch so it does not automatically install on systems that have the auto-update feature enabled. Also, the Windows Update website no longer displays the patch as critical, but as recommended, a Microsoft spokesman said.
"These steps were taken to give customers the opportunity to evaluate the patch before installing it," the spokesman said.
Microsoft is actively involved in finding a solution to the performance problems, in addition to investigating how the faulty patch made it through Microsoft's patch review process, Toulouse said.
Microsoft said it will also publish an article that describes what environmental factors produce slow downs when combined with the XP patch and what can be done to reduce the impact of the slow downs should they occur.