Microsoft this week rolled out its monthly security update, which includes fixes for 96 CVEs in Windows, Skype, Office, Internet Explorer, and Microsoft Edge. This massive wave of releases provided updates for unsupported services Windows XP and Windows Server 2003.
Although fixes for unsupported platforms are still created under custom support agreements with business customers who have paid for them, it is extremely rare for Microsoft to release patches for end-of-life operating systems to the general public. (They issued an out-of-band patch for Internet Explorer on XP in 2014 shortly after support ended.)
Microsoft security engineers conducted an assessment of the current threat landscape and made the uncommon decision to provide patches for systems they no longer support.
"Today … we have taken action to provide additional critical security updates to address vulnerabilities that are at heightened risk of exploitation due to past nation-state activity and disclosures," writes Eric Doerr, general manager for Microsoft's Security Response Center.
Of the issues addressed in this release, 18 are rated Critical, 76 are Important, one is rated Moderate, and one is of Low severity. Customers with automatic updates enabled do not need to take additional action; those updating older platforms should patch as soon as possible.
A few key fixes enterprise users should focus on include CVE-2017-8543, a patch that covers a Remote Code Execution Vulnerability in the Windows OS. This flaw lets attackers assume control over a victim machine by sending an SMB request to Windows Search.
"Attackers are mostly relying on unpatched systems," says Amol Sarwate, director of engineering at Qualys. He adds that businesses should note CVE-2017-8507, which lets attackers send malicious emails and take complete control when a user views it in Outlook.
"This month's release shows that security problems from years ago still exist, even in modern software," says Dustin Childs, communications manager for the Zero Day Initiative. "You have bugs that look like bugs used in Stuxnet. You have bugs that look like worms. You have Flash and Shockwave problems that never seem to go away."
While the bugs stay the same, he continues, the threat is changing from miscreants and criminals to nation-states and more sophisticated attackers.
Many of this month's patches were created to avoid another WannaCry, which primarily hit Windows 7 machines but could also happen on Windows 10. Microsoft issued an emergency patch for Windows XP following the attack, and many fixes in this month's security release protect against potential attacks similar to WannaCry, writes Adrienne Hall, general manager for Microsoft's Cyber Defense Operations Center, in the Windows Blog.
The company also faces a threat presented by Shadow Brokers, the hacker group which recently began a subscription service to sell exploits allegedly belonging to the NSA. Microsoft confirmed to ZDNet that its latest wave of patches fixed three vulnerabilities built by the NSA. All were for problems it initially would not fix because they affected older Windows systems.
Microsoft warns this level of support cannot be expected in the long term; this week's patches for Windows XP and Server 2003 should be considered a temporary solution. Customers are urged to upgrade to newer systems, which have security protections older versions lack.
"Our decision today to release these security updates for platforms not in extended support should not be viewed as a departure from our standard servicing policies," Doerr says.
Sarwate says he does not expect Microsoft to continue support for unpatched systems but adds this is a "double-edged sword" for customer security.
"If they do not release those patches, they are putting industry operating systems at risk," he says. "On the other hand, if they do this frequently, it takes away from their goal of getting people out of Windows XP and upgrading to older operating systems."
Unfortunately, sometimes upgrading is not possible because of regulatory or other constraints, says Childs. Oftentimes businesses follow the adage of "if it ain't broken, don't fix it," a mindset that will put their organizations in danger as attackers target unsupported systems.
Outside of system upgrades, businesses can take steps to protect against attacks on Microsoft systems, experts say: disable old and unused protocols, do not use administrative privileges, protect with external entities like firewalls, and of course, apply patches as they are released.
Attacks of the future could be worse than WannaCry, warns Sean Dillon, senior security analyst for RiskSense.
"The greatest threat is not necessarily ransomware," he says. "Installation of stealthier malware, such as banking spyware and key-loggers, as well as exfiltration of intellectual property or classified information, is a huge risk if an attacker is able to breach into the internal network and install back-doors."