Patch Tuesday Microsoft released two "critical" patches and five "important" security updates on Tuesday - but none of the fixes address a zero-day vulnerability in Internet Explorer discovered two weeks ago.
The two critical patches tackle a remote-code execution vulnerability in the Windows Print Spooler (MS13-001) and similarly serious bugs in Microsoft XML Core Services (MS13-002). The latter vulnerability is particularly nasty and affects Windows XP through to Windows 8 and RT, allowing miscreants to take over a compromised system from afar.
The remaining "important" security fixes grapple two further bugs in the Windows operating system: one in System Centre Operations Manager (SCOM), one in .NET and one in OData Services.
None of this plugs the so-called "Mad Woman in the Attic" hole in older but still widely used builds of Redmond's web browser Internet Explorer, namely versions 6, 7 and 8. The software giant rushed out an emergency sticking plaster to thwart attacks that exploit this vulnerability, but researchers and hackers were able to circumvent the temporary defence.
"Although Microsoft has issued a fix-it for the zero-day vulnerability in Internet Explorer a bypass for the fix-it has already been published, which means that people who are still using Internet Explorer 6, 7 or 8 will still be vulnerable until probably next month’s Patch Tuesday," explained Ziv Mador, director of research at security biz Trustwave.
"Of course if you can’t wait until next month’s Patch Tuesday you could also just update your browser to Internet Explorer 9 or 10 or Chrome or Firefox."
The unresolved zero-day vulnerability affects 90 per cent of the Internet Explorer installed base, according to cloud security firm Qualys. Of the patches that have been released in January, the XML Core Services vulnerability ought to take precedence, according to Wolfgang Kandek, CTO at Qualys.
"MS13-002 is the most important patch in the lineup," Kandek explained yesterday.
"It addresses a vulnerability in the MSXML library, which is an integral part of many Microsoft software packages. It affects every Windows version from XP to RT, plus all Office versions and a number of other packages, such as Sharepoint and Groove. The most likely attack vector is a malicious webpage. But an email with an Office document attachment can also be a viable alternative for attackers."
Andrew Storms, director of security operations for nCircle, agreed that fixing the XML bug was a top priority. The print-spooler bug is less easily exploited. "Print spooler bugs played a role in the infamous Stuxnet malware, but this bug isn't anything like the vulnerability Stuxnet exploited," Storms added.
It wouldn't be a security patch story without mentioning…
Adobe, in related news, announced a new version of its Reader and Acrobat software complete with security fixes. The cross-platform update needs to be applied to Windows, Mac OS X and Linux machines. A separate advisory details workarounds to defend against three Adobe ColdFusion vulnerabilities, pending the arrival of a more comprehensive patch from the media software biz.
Last, but not least, Mozilla has upgraded Firefox yet again: the open-source web browser is now up to version 18. Release notes from the non-profit organisation are here, and details of the security fixes bundled can be found here. The update includes 12 critical fixes including a revocation fix for the recently bungled Turktrust web security certificates, patches for a slew of memory-related security holes and a couple of buffer overflow vulnerabilities, although use-after-free bugs predominate.