Microsoft
CVE-2016-0099
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V14 - Configuration Dependency management, component inventory
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | High risk. A reliable local privilege escalation on modern Windows versions. Used by commodity malware and ransomware as a post-exploitation step to elevate from user-level access to SYSTEM. |
| Exploit ScenarioDerived | After gaining initial access via phishing, malware invokes the Secondary Logon Service with crafted parameters. The handle processing flaw allows the malware to escalate to SYSTEM and disable security products before deploying ransomware. |
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Alert meAnalysisAIv1 – Mar 26, 2026
Windows Secondary Logon Service improperly processes request handles, allowing local users to escalate privileges to SYSTEM on Windows Vista through Windows 10 via a crafted application.
Earlier versions of this analysis (1)
The Secondary Logon Service in Windows fails to properly process request handles during impersonation, enabling local privilege escalation from standard user to SYSTEM.
RemediationAI
Apply Microsoft security update MS16-032. Modern Windows versions have addressed this class of vulnerability. Ensure least-privilege principle is enforced.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The CWE-120 buffer overflow in the Secondary Logon Service (seclogon.dll) occurs during handle duplication. An attacker can craft requests that cause the service to impersonate the calling token with elevated privileges, then hijack the impersonation context.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
The Secondary Logon Service in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 does not properly process request handles, which allows local users to gain privileges via a crafted application, aka "Secondary Logon Elevation of Privilege Vulnerability."
Executive ViewAI
CVE-2016-0099 presents notable security risk, a buffer overflow vulnerability rated CVSS 7.8. Exploitation could allow attackers to corrupt memory, crash the application, or potentially execute arbitrary code. This vulnerability is actively exploited in the wild (KEV-listed) and requires immediate remediation. A patch is available and should be applied as part of regular vulnerability management.
Apply vendor patch. If immediate patching is not feasible: (1) Enable ASLR and DEP where available; (2) Implement network segmentation; (3) Monitor for exploitation indicators.
Threat Intelligence Overview
NVD
CVE.org
CISA KEV
EPSS
Exploit-DB
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
GitHub PoC