Microsoft Corp. is working on a patch for a potentially serious security hole in fully patched versions of Windows XP Service Pack 2.
The software makers confirmation follows public disclosure of the vulnerability by a private security researcher who goes by the moniker "badpack3t."
The researcher posted an advisory describing the issue as a remote kernel DoS (denial of service) flaw affecting Windows XP SP2 with the default firewall turned on.
"I have been working with Microsoft to get a patch out for this. I notified them [May 4] about the flaw, and they have been working on it since then. Microsoft told me the patch was going to be released in August," said the researcher in the advisory.
The discovery has triggered many discussions on security mailing lists, with some experts claiming there is a chance that the bug could be used to execute code remotely.
Pedro Bueno, an incident handler at The SANS Institutes Internet Storm Center, said the flaw resides in the Windows Remote Desktop feature that allows XP users to remotely control computers from another PC.
A spokesperson for Microsoft, in Redmond, Wash., confirmed that the company is investigating the public reports, but she downplayed the severity of the vulnerability.
"The initial investigation has found that neither of these [involves] remote code execution, and Microsoft has not been made aware of attacks that try to use the reported vulnerabilities or of customer impact at this time," the spokesperson said in a statement.
When vulnerabilities are publicly reported before a patch is available, Microsoft has promised to issue security advisories with mitigation guidance and workarounds, but, in this case, the company has not yet decided if an advisory is necessary.
Secunia, a provider of security alerts and intelligence in Copenhagen, Denmark, also issued a separate alert for a DoS bug in the Windows Network Connections Service. Affected products include Microsoft Windows 2000 Server, Advanced Server, Datacenter Server and Professional, and Microsoft Windows XP Home Edition and Professional.
"The vulnerability is caused by an error in a function in netman.dll when a large integer is supplied as argument. Successful exploitation crashes the Network Connections Service," the Secunia warning said.
In the absence of a fix from Microsoft, Secunia recommended that only trusted users be granted access to affected systems.
Ryan Naraine is a senior writer for eWEEK.com.