CVE-2018-8120
Microsoft Win32k Privilege Escalation Vulnerability
Description
CVE-2018-8120 is a high-severity improper resource management vulnerability affecting Microsoft Win32k. A privilege escalation vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory. This vulnerability has been associated with ransomware campaigns, heightening its risk profile. CISA has added CVE-2018-8120 to the Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. With an EPSS score of 94.12% (99.9th percentile), this vulnerability has a very high probability of being exploited.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 7 | - |
| microsoft | windows server 2008 | -; r2 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- http://www.securityfocus.com/bid/104034(Broken Link, Third Party Advisory, VDB Entry)
- http://www.securitytracker.com/id/1040849(Broken Link, Third Party Advisory, VDB Entry)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8120(Patch, Vendor Advisory)
- https://www.exploit-db.com/exploits/45653/(Exploit, Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8120(US Government Resource)
Weakness Type
CWE-404: Improper Resource Shutdown or Release
Improper Resource Shutdown or Release occurs when software fails to properly close, release, or cleanup resources after they are no longer needed. This includes file handles, database connections, network sockets, memory allocations, locks, and other system resources. In the case of CVE-2018-8120, this weakness manifests in Microsoft Win32k where a privilege escalation vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory.
Learn more: CWE-404 — Improper Resource Shutdown or Release
Impact Analysis
CVE-2018-8120 represents a significant threat to organizations using Microsoft Win32k, carrying a CVSS score of 7. Successful exploitation can fully compromise the confidentiality, integrity, and availability of affected systems. Attackers can access sensitive data, modify system configurations or data, and disrupt service availability. The documented association with ransomware campaigns makes this vulnerability particularly dangerous, as threat actors actively leverage it for initial access or privilege escalation in ransomware operations.
Exploit Maturity
CVE-2018-8120 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming real-world exploitation. The EPSS score of 94.12% (99.9th percentile) places it among the most likely vulnerabilities to be exploited, reflecting widespread and active exploitation activity. Public exploit code is available, lowering the barrier for attackers and increasing the urgency to patch. This vulnerability has been linked to ransomware campaigns, indicating that well-resourced threat actors are actively incorporating it into their attack chains.
Remediation
- Apply vendor patches immediately as required by CISA KEV: Apply updates per vendor instructions. Update Microsoft Win32k to the latest available version that addresses this vulnerability.
- Until the patch is applied, enforce the principle of least privilege by limiting local user access to only those who require it, and restrict the ability to execute untrusted applications on affected systems.
- Given the ransomware association, ensure endpoint detection and response (EDR) solutions are active on all affected systems and monitor for indicators of compromise including unusual process execution, file encryption activity, and lateral movement.
- Verify the patch deployment across all instances of Microsoft Win32k in your environment using vulnerability scanning to confirm no systems remain exposed.
- Review and update your organization's vulnerability management process to ensure CISA KEV entries with a remediation deadline of 2022-04-05 are addressed within the required timeframe.
Technical Details
CVE-2018-8120 is classified under CWE-404 (Improper Resource Shutdown or Release) affecting Microsoft Win32k. A privilege escalation vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory. The vulnerability is exploitable with local access to the target system, though the attack complexity is high, requiring specific conditions to be met, requiring low-level privileges. The CVSS 3.1 base score of 7 (HIGH) reflects high confidentiality impact, high integrity impact, and high availability impact.
Frequently Asked Questions
Is CVE-2018-8120 being actively exploited?
Yes. CVE-2018-8120 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The EPSS score of 94.12% (99.9th percentile) indicates a very high probability of exploitation. Public exploit code is available, further increasing the risk. This vulnerability has also been associated with ransomware campaigns.
What products are affected by CVE-2018-8120?
CVE-2018-8120 primarily affects Microsoft Win32k, as well as Microsoft Windows 7, Microsoft Windows Server 2008. Organizations should check whether any instances of the affected software are running in their environment.
How do I fix CVE-2018-8120?
Apply updates per vendor instructions. Until the update is applied, limit local access privileges and monitor for suspicious activity on affected systems.
How severe is CVE-2018-8120?
CVE-2018-8120 has a CVSS 3.1 score of 7, rated HIGH. This high severity rating indicates significant potential impact on affected systems. The association with ransomware campaigns further elevates the operational risk posed by this vulnerability.
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