High

Win32k Elevation of Privilege Vulnerability

IdentifiersCVE-2018-8641CWE-416

CVE-2018-8641 is a Windows local elevation-of-privilege vulnerability in the Win32k kernel-mode driver caused by improper handling of objects in memory. Available reporting characterizes the flaw as a double-free in win32k!xxxTrackPopupMenuEx. Successful exploitation allows a local attacker to corrupt kernel memory and leverage the resulting primitive to elevate privileges. The vulnerability affects multiple Windows client and server releases, including Windows 7, Windows 8.1, Windows 10, Windows RT 8.1, and several Windows Server versions from 2008 through 2019.

For your environment

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation enables local privilege escalation to elevated or SYSTEM-level execution on a vulnerable Windows host. In observed use, the flaw was used as a post-compromise privilege-escalation step to escape a low-privilege context and execute follow-on malware with full system privileges.

Mitigation

If you can’t patch tonight, do this now.

Until patching is complete, reduce exposure by minimizing opportunities for local code execution, restricting user ability to run untrusted code, enforcing least privilege, and hardening browser and application attack surfaces that commonly deliver initial malware execution. Application control, exploit protection, endpoint detection, and rapid containment of low-privilege malware infections can limit use of this vulnerability as a secondary privilege-escalation stage.

Remediation

Patch, then assume compromise.

Apply Microsoft's security updates released for CVE-2018-8641 in December 2018 across all affected Windows client and server systems. Ensure unsupported or legacy Windows versions are upgraded or retired where possible, and verify that all relevant cumulative or security-only updates covering the Win32k kernel-mode driver are installed.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Microsoft CorporationWindows 10operating_system

Microsoft CorporationWindows 8.1operating_system

Microsoft CorporationWindows Rt 8.1operating_system

Microsoft CorporationWindows Server 2008operating_system

Microsoft CorporationWindows Server 2012operating_system

Microsoft CorporationWindows Server 2016operating_system

Microsoft CorporationWindows Server 2019operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

3 SOURCESView more in app

checkpoint research blogNews

Oct 2, 2020

Graphology of an Exploit - Hunting for exploits by looking for the author's fingerprints - Check Point Research

A likely Windows local privilege escalation vulnerability involving a double free in win32k!xxxTrackPopupMenuEx, attributed here conservatively as CVE-2018-8641.

securelistNews

Sep 3, 2020

IT threat evolution Q2 2020

A Windows elevation-of-privilege vulnerability referenced as being exploited by the Magnitude Exploit Kit using an exploit described as previously unknown by the authors.

securelistNews

Jul 13, 2020

Magnitude exploit kit - evolution | Securelist

A win32k kernel driver elevation-of-privilege vulnerability used by Magnitude EK, with a previously unknown exploit attributed by the researcher to the exploit writer Volodya/BuggiCorp.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware2

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity