Patch your Windows 10 PC, now! Hackers are exploiting a zero-day flaw

Patch your Windows 10 device quick, as hackers are currently taking advantage of a zero-day “Double Kill” flaw in Internet Explorer to infect PCs across the globe. The fix is part of Microsoft’s latest Patch Tuesday update for Windows 10, addressing the vulnerability discovered by the Qihoo 360 Core Security team in late April. The flaw is officially labeled as CVE-2018-8174, ignoring the 360 Core Security team’s “Double Kill” codename. 

According to the team, hackers can embed a malicious website inside an Office document. Once opened, the embedded site deploys malicious code and its payload from a remote web-based server. The attack also bypasses the User Account Control component in Windows 10, acquiring administrator-level privileges. The attack is executed within the system memory as well, thus you’ll find no evidence of foul play on the device’s local storage. 

Microsoft says the problem resides in the VBScript engine. That’s short for Visual Basic Scripting, Microsoft’s programming language included in Internet Explorer for creating system management tools. The vulnerability resides in the way this engine handles objects in memory, allowing hackers to inject code into memory and gain the same user rights as the current user. 

“In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked ‘safe for initialization’ in an application or Microsoft Office document that hosts the IE rendering engine,” Microsoft says. 

But that’s not all. Hackers could also take advantage of websites that “accept or host user-provided content or advertisements” by injecting specifically crafted content. The good news here is that the only attack vector discovered thus far is by injecting an Office document with a malicious website. Despite that limitation, a successful attack provides hackers with complete control of the victim’s PC without their knowledge. 

While many Windows 10 device owners may scratch their heads wondering why this Internet Explorer flaw is relevant, the browser still remains as a Windows component for legacy support. Many websites, applications, and corporations still rely on elements that are only compatible with Internet Explorer and have not moved on to the newer technology offered in Microsoft Edge.  

The 360 Security Center team said this is the first advanced persistent threat (APT) campaign to use an Office document carrying this specific Internet Explorer exploit payload. Using Office documents, however, is nothing new. 

“In recent years, we have discovered a rising trend that Office documents have taken the center stage of APT attacks,” the security team said. “Opening any malicious documents with “double kill” allows attackers to control victims’ computers without their knowledge, making ransomware infection, eavesdropping, and data leakage convenient and stealthy.” 

As always, never open a document from an unknown source. Also keep your Windows 10 PC up to date on a security level given Microsoft’s operating system is a highly popular target. Keep your firewall locked and loaded and your anti-virus solution updated as well. You can remove Internet Explorer by following these instructions.