dbcve.org
Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 24 Mar 2022. Known ransomware use
Windows 10 1507Operating system · Microsoft

CVE-2016-0099

HIGH · 7.8 CVSS v3.1 Published 2016-03-09
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
96/100
Remediation priority · Urgent
In the wild Ransomware Public exploit Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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."

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a local privilege escalation vulnerability in the Windows Secondary Logon Service (scardsvr.dll). The service fails to properly validate or sanitize request handles when processing logon requests, allowing a local authenticated attacker to manipulate handle processing and execute arbitrary code with elevated privileges. The vulnerability requires the attacker to have local access to the system and the ability to run a specially crafted application.

MitigationApply the Microsoft security update (MS16-032) to all affected Windows systems. This is a standard Windows Update patch that corrects the handle processing logic in the Secondary Logon Service. After patching, verify the service functions correctly and consider restricting who can create new processes with alternate credentials.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows 10 1507Operating system
Affected:all versions
Windows 10 1511Operating system
Affected:all versions
Windows 7Operating system
Affected:all versions
Windows 8.1Operating system
Affected:all versions
Windows Server 2008Operating system
Affected:all versions= r2
Windows Server 2012Operating system
Affected:all versions= r2
Windows VistaOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if MS16-032 security update is installed
    Run 'wmic qfe get hotfixid,installedon | findstr /i "MS16-032"' or check Windows Update history for security update KB3143140
    Affected if The update is NOT installed - the system is vulnerable
  2. Verify Secondary Logon service is running
    Open Services (services.msc) or run 'sc query seclogon' to check if the Secondary Logon service (seclogon) status is Running
    Affected if Service is Running and MS16-032 is not installed - the vulnerability is present and exploitable
  3. Check scardsvr.dll file version
    Locate scardsvr.dll in %SystemRoot%\System32\ (or run 'dir %SystemRoot%\System32\scardsvr.dll') and check the File Version property
    Affected if File version is lower than the patched version and MS16-032 is not installed - likely vulnerable
  4. Confirm Windows version is in affected range
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the Windows version
    Affected if Version is Windows 10 1507, 10 1511, 7, 8.1, Server 2008, 2008 R2, 2012, 2012 R2, or Vista WITHOUT MS16-032 applied - system is affected

If the system runs a Windows version listed in the affected products and MS16-032 (KB3143140) is not installed, the system is vulnerable to CVE-2016-0099 privilege escalation via the Secondary Logon Service.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch docs.microsoft.com →
Interim mitigation

Apply the Microsoft security update (MS16-032) to all affected Windows systems. This is a standard Windows Update patch that corrects the handle processing logic in the Secondary Logon Service. After patching, verify the service functions correctly and consider restricting who can create new processes with alternate credentials.

Recommended fix High confidence

March 2016 Security Updates (MS16-034) - install the appropriate update for your Windows version

  1. Verify the current Windows version by running 'winver' or 'systeminfo' in Command Prompt
  2. Open Windows Update by pressing Windows Key + I, then selecting Update & Security > Windows Update
  3. Click 'Check for updates' and wait for the scan to complete
  4. If updates are available, install all recommended security updates, particularly the March 2016 security updates (MS16-034)
  5. Restart the computer when prompted to complete the installation
  6. Alternatively, manually download the security update for your specific Windows version from the Microsoft Security Bulletin MS16-034 at https://docs.microsoft.com/en-us/security-updates/securitybulletins/2016/ms16-034
Caveat Ensure compatibility with other March 2016 patches; some older systems may require restart

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1507 Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2016-0099 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-0099 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data