Pierluigi Paganini October 22, 2014

Security experts at Google and McAfee have discovered a new Zero-day vulnerability in Microsoft OLE being exploited in targeted attacks.

Early this week,  Microsoft issued the security advisory 3010060 to warn its customer of a new Zero-Day vulnerability that affects all supported versions of Windows OS except, Windows Server 2003.

The OLE Packager is the component that is affected by the zero-day, which was discovered by researchers at McAfee and Google. Curiously the component was just patched this month in MS14-060, but Microsoft,  in response to this latest flaw, has released a Fix It package for PowerPoint, and encouraged the use of EMET 5.0.

The most concerning things related to the Microsoft zero-day flaw is that it is already being exploited by threat actors in targeted attacks.

“The vulnerability could allow remote code execution if a user opens a specially crafted Microsoft Office file that contains an OLE object. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user,” the advisory explained.”At this time, we are aware of limited, targeted attacks that attempt to exploit the vulnerability through Microsoft PowerPoint.” confirming the voice that bad actors are already exploiting the zero-day in limited cases.

The OLE (Object Linking and Embedding) is a proprietary technology developed by Microsoft that allows embedding and linking to documents and other objects. As explained by the experts at Microsoft, the vulnerability in Microsoft OLE, coded as CVE-2014-6352, could allow remote code execution, this is possible if a Microsoft user opens a specially crafted Microsoft Office file that contains an OLE object.

The file could be sent via email to the victims in a classic spear-phishing attack or the attacker could serve it through a compromised website in a classic watering hole attack.

The security advisory reports the following mitigation factors:

• In observed attacks, User Account Control (UAC) displays a consent prompt or an elevation prompt, depending on the privileges of the current user, before a file containing the exploit is executed. UAC is enabled by default on Windows Vista and newer releases of Microsoft Windows.
• An attacker who successfully exploited this vulnerability could gain the same user rights as the current user. Customers whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.
• In a web-based attack scenario, an attacker could host a website that contains a webpage that contains a specially crafted Office file that is used to attempt to exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these websites. Instead, an attacker would have to convince users to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes users to the attacker’s website.
• Files from the Internet and from other potentially unsafe locations can contain viruses, worms, or other kinds of malware that can harm your computer. To help protect your computer, files from these potentially unsafe locations are opened in Protected View. By using Protected View, you can read a file and see its contents while reducing the risks. Protected View is enabled by default.

The principal problem is that despite the exploit of the flaw trigger a warning, users often ignore them, the issue appears very serious in corporate environments, where executives and remote users are often granted administrative rights on their systems.

Pierluigi Paganini

(Security Affairs – Microsoft zero-day, hacking, OLE )