CVE-2016-0151
Microsoft Windows CSRSS Security Feature Bypass Vulnerability
Description
CVE-2016-0151 is a privilege escalation vulnerability (CWE-269) in the Microsoft Windows Client-Server Run-time Subsystem (CSRSS) that allows a locally authenticated attacker to execute arbitrary code with SYSTEM privileges. The flaw exists because CSRSS improperly handles certain process token requests, enabling an attacker who has already gained user-level access to elevate their privileges to the highest system level. CISA has confirmed active exploitation and added CVE-2016-0151 to the Known Exploited Vulnerabilities catalog, and the vulnerability is associated with known ransomware campaigns. With an EPSS score of 44.1%, CVE-2016-0151 represents a significant local privilege escalation threat, particularly in post-exploitation scenarios.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 10 1507 | - |
| microsoft | windows 10 1511 | - |
| microsoft | windows 8.1 | - |
| microsoft | windows rt 8.1 | - |
| microsoft | windows server 2012 | -; r2 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://www.securitytracker.com/id/1035544(Broken Link, Third Party Advisory, VDB Entry)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2016/ms16-048(Patch, Vendor Advisory)
- https://www.exploit-db.com/exploits/39740/(Exploit, Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-0151(US Government Resource)
Weakness Type
CWE-269: Improper Privilege Management
CWE-269 describes a weakness where software does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control that allows the actor to perform unauthorized actions. In CVE-2016-0151, the Windows CSRSS component fails to properly validate privilege levels during certain operations, allowing a local attacker to escalate from standard user privileges to SYSTEM-level access.
Learn more: CWE-269 — Improper Privilege Management
Impact Analysis
CVE-2016-0151 enables a locally authenticated attacker to escalate privileges from a standard user account to SYSTEM, the highest privilege level on Windows systems. While the attack vector is local (requiring initial user-level access), the impact is severe: SYSTEM-level access grants complete control over the operating system, including the ability to install rootkits, modify security policies, create administrative accounts, access all files and credentials, and disable security software. The confirmed association with ransomware campaigns makes this vulnerability particularly dangerous, as ransomware operators routinely chain initial access exploits with privilege escalation vulnerabilities like CVE-2016-0151 to achieve full domain compromise. The EPSS score of 44.1% reflects meaningful real-world exploitation probability.
Exploit Maturity
CVE-2016-0151 is confirmed as actively exploited in the wild by CISA and is listed in the Known Exploited Vulnerabilities catalog. Notably, this vulnerability is associated with known ransomware campaigns, indicating it is used as part of multi-stage attack chains where initial access is followed by privilege escalation to achieve full system control. The EPSS score of 44.1% indicates substantial exploitation activity, and the local nature of the attack makes it a high-value target for post-exploitation toolkits and lateral movement frameworks.
Remediation
- Apply the Microsoft security update MS16-048 (April 2016) to patch the CSRSS vulnerability on all affected Windows systems immediately.
- Implement the principle of least privilege across all user accounts and service accounts to reduce the impact of privilege escalation vulnerabilities.
- Deploy endpoint detection and response (EDR) solutions with behavioral detection capabilities to identify privilege escalation attempts and post-exploitation activity.
- Enable and monitor Windows Security Event logs for suspicious process creation events, particularly processes spawned with SYSTEM privileges from unexpected parent processes.
- Segment networks and restrict lateral movement to limit the blast radius of compromised systems where privilege escalation has occurred.
Technical Details
CVE-2016-0151 is a privilege escalation vulnerability (CWE-269) in the Windows Client-Server Run-time Subsystem (CSRSS), a critical Windows component responsible for console windows, thread creation and deletion, and other essential operating system functions. The flaw occurs when CSRSS improperly handles certain process management operations, allowing a locally authenticated attacker to manipulate process tokens or exploit a race condition in privilege validation to execute arbitrary code with SYSTEM privileges. Because CSRSS runs as a privileged system process, successful exploitation elevates the attacker from their current user context to full SYSTEM-level access without requiring any additional authentication. The local attack vector means the attacker must first obtain code execution on the target system, but once achieved, this vulnerability provides reliable and complete privilege escalation.
Frequently Asked Questions
Is CVE-2016-0151 being actively exploited?
Yes. CVE-2016-0151 is confirmed as actively exploited in the wild by CISA and is listed in the KEV catalog. The vulnerability is associated with known ransomware campaigns, indicating it is actively used in real-world attack chains.
What products are affected by CVE-2016-0151?
CVE-2016-0151 affects the Client-Server Run-time Subsystem (CSRSS) component across multiple versions of Microsoft Windows, including Windows Vista, Windows 7, Windows 8.1, Windows 10, Windows Server 2008, Windows Server 2012, and Windows Server 2016.
How do I fix CVE-2016-0151?
Apply the Microsoft security update MS16-048 (April 2016) on all affected Windows systems. Additionally, implement least-privilege principles, deploy EDR solutions, and monitor for suspicious privilege escalation activity.
How severe is CVE-2016-0151?
CVE-2016-0151 is a high-severity privilege escalation vulnerability that allows elevation from standard user to SYSTEM privileges. Its confirmed use in ransomware campaigns and CISA KEV listing make it a critical patching priority, particularly for organizations facing ransomware threats.
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