Clement Lecigne of Google’s Threat Analysis Group has reported exploitation of an Internet Explorer vulnerability, CVE-2018-8653, prompting an out-of-band patch from Microsoft.
On December 19, Microsoft released a critical out-of-band (OOB) patch for a remote code execution (RCE) vulnerability in Internet Explorer (IE). This vulnerability affects all versions of IE including Windows 7, Windows 8.1, Windows 10, Windows Server 2008 (Internet Explorer 9), Windows Server 2012 (Internet Explorer 10), Windows Server 2016 and Windows Server 2019.
A remote code execution vulnerability was found in IE’s memory handling in Jscript.dll. An attacker could corrupt IE’s memory in a way that allows code execution on the affected system. The attacker would have the same rights as the active user, including administrators.
An attacker would have to convince a user to visit a malicious website, which could then exploit this vulnerability, executing code on the user’s local machine. Email- or social media-based spear phishing attempts are the most likely methods for exploitation.
Microsoft hasn’t given any specific details, but the advisory does show that the vulnerability has already been publicly exploited. This increases the likelihood of additional exploitation against unpatched systems in the future.
Urgently required actions
Organizations and individual users are strongly encouraged to apply the available patches, or relevant workaround, provided by Microsoft from its advisory page here.
Identifying affected systems
A list of Nessus plugins to identify this vulnerability will appear here as they’re released.