Scallywags are using an unpatched vulnerability in an ActiveX component to distribute malware, Microsoft warned on Monday. The development adds to already pressing unresolved Internet Explorer security bug woes.
No patch is available for the Office Web Components ActiveX security hole, although there are workarounds which can be automated for enterprise rollouts. The flawed component is used by IE to display Excel spreadsheets, greatly increasing the scope for mischief. Win XP and Win 2003 systems are particularly at risk, while the additional security controls in Vista cover Microsoft's modesty.
Redmond said it's aware of attacks against the security bug, which would involve tricking users into visiting booby-trapped websites. McAfee warns of targeted Trojan attacks based on the vulnerability circulating in China.
The timing of the advisory, a day before Microsoft's monthly Patch Tuesday update, suggests it's highly unlikely that a fix will become available until August at the earliest.
Monday's advisory adds to the list of pending Internet Explorer vulnerabilities, most notably an unpatched flaw in Microsoft Video ActiveX Control that has become the target of widespread exploitation since earlier this month. The flaw is particularly serious because Internet Explorer users can get hit simply by straying onto a hacker-controlled website, providing they are running Windows XP. Vista, as with the latest ActiveX bug, is far less susceptible.
Six updates - three of which address critical flaws in Windows - are due from Microsoft later on Tuesday, as explained here. Redmond is expected to patch the more pressing (and longstanding) online video ActiveX bug later.
Nonetheless, the current outbreak of unpatched ActiveX bugs has prompted some security watchers, including the SANS Institute's Internet Storm Centre (here) and F-Secure (here), to advise punters to consider using alternative browsers in preference to Internet Explorer. ®