The worst of the bunch, an attack called ExplodingCan (CVE-2017-7269), targets older versions of Microsoft’s Internet Information Services (IIS) webserver, version 6.0 in particular, and enables an attacker to gain remote code execution on a Windows 2003 server.
All three attacks allow an adversary to gain remote code execution; one is EsteemAudit, a vulnerability in the Windows Remote Desktop Protocol (RDP) (CVE-2017-0176), while the other is EnglishmanDentist (CVE-2017-8487), a bug in OLE (Object Linking and Embedding). Microsoft said the patches are available for manual download.
ExplodingCan merits a closer look because of the wide deployment of IIS 6.0.
“Generally, when you put a Windows machine on the internet, it’s going to be a server and it’s going to run a webserver, so there are production machines on the internet running IIS 6.0 right now,” said Sean Dillon, senior analyst at RiskSense and one of the first to analyze the NSA’s EternalBlue exploit that spread WannaCry ransomware on May 12.
“It’s probably already been exploited for months now,” Dillon said. “At least now there’s a fix that’s publicly available.”
Microsoft released a hefty load of patches for supported products and services on Tuesday as part of its normal Patch Tuesday update cycle. Normally, patches for unsupported versions of Windows are available only for Microsoft customers on an expensive extended support contract. The company’s decision to make all of those fixes public on Tuesday, it said, was prompted by an elevated risk for “destructive cyber attacks.”
“Due to the elevated risk for destructive cyber attacks at this time, we made the decision to take this action because applying these updates provides further protection against potential attacks with characteristics similar to WannaCrypt,” said Adrienne Hall, general manager of Microsoft’s Cyber Defense Operations Center.
“In reviewing the updates for this month, some vulnerabilities were identified that pose elevated risk of cyber attacks by government organizations, sometimes referred to as nation-state actors or other copycat organizations,” Hall said. “To address this risk, today we are providing additional security updates along with our regular Update Tuesday service. These security updates are being made available to all customers, including those using older versions of Windows.”
The ShadowBrokers’ leak in April unleashed a number of powerful Windows attacks into the public, allegedly belonging to the Equation Group, which is widely believed to the U.S. National Security Agency. Criminals and other nation states have already been leveraging the attacks to spread not only WannaCry ransomware, but also crytpocurrency mining utilities and other types of malware.
Microsoft said customers should not expect this type of patch release for unsupported products to become the norm. Some experts have been critical of Microsot, which also made a similar update available for unsupported products hours after the WannaCry outbreak.
I wish MS would stop releasing patches for xp/2003 it really harms efforts to get rid of legacy in the corporates
— Quentyn Taylor (@quentynblog) June 13, 2017
Oh no. Take Windows XP off life support. Though it cannot die with dignity, it must be allowed to die. It will be messy. But this is cruel. https://t.co/euZVdTLC0z
— Katie Moussouris (@k8em0) June 13, 2017
“It was the right move by Microsoft,” Dillon said. “We saw the damage it can cause with WannaCry. “Some of the most-used infrastructure, like SCADA systems, still run on XP whether they’re getting patches or not. When you have critical things [running on XP], it’s a good thing they released, but it should only be looked at as a temporary solution and people should look to upgrade off of legacy versions.”
Some third-party services such as 0patch have provided micro-patches for some of these vulnerabilities on legacy versions, even before the ShadowBrokers leak, Dillon said. “Hopefully people who are running legacy systems have looked into other means of patching beside official fixes,” he said. “Although, this is great that there’s an official fix.”
The remaining two vulnerabilities are a lesser severity but should be patched nonetheless on legacy systems.
EsteemAudit affects RDP, but only on XP and did not require a patch for modern versions of Windows. According to Microsoft, the vulnerability exists if the RDP server has smart card authentication enabled.
EnglishmanDentist, meanwhile, is triggered because Windows OLE fails to properly validate user input, Microsoft said.
“There’s a whole wide assortment of exploits that were leaked, and we’ve only seen a few of them actively used at a mass scale. This is just plugging a hole before it becomes a bigger problem,” Dillon said.