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LyncApplication · Microsoft

CVE-2012-1849

HIGH · 9.3 CVSS v2.0 Published 2012-06-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Untrusted search path vulnerability in Microsoft Lync 2010, 2010 Attendee, and 2010 Attendant allows local users to gain privileges via a Trojan horse DLL in the current working directory, as demonstrated by a directory that contains a .ocsmeet file, aka "Lync Insecure Library Loading 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

Microsoft Lync 2010, 2010 Attendee, and 2010 Attendant contain an insecure library loading (DLL hijacking) vulnerability where the application loads DLLs from the current working directory without proper validation. Local attackers can place a malicious DLL in directories containing .ocsmeet meeting files, which gets loaded with elevated privileges when a user launches Lync from that directory, resulting in privilege escalation.

MitigationApply Microsoft's security update for this vulnerability (MS12-037) and ensure users do not launch Lync from untrusted or shared network directories containing .ocsmeet files.

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
LyncApplication
Affected:= 2010

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
Network
Complexity
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:M/Au:N/C:C/I:C/A:C

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. Verify Microsoft Lync 2010 is installed
    Open Control Panel > Programs and Features, or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Select-Object DisplayName, DisplayVersion' to list installed Microsoft Lync products
    Affected if Microsoft Lync 2010, Lync 2010 Attendee, or Lync 2010 Attendant appears in the installed programs list
  2. Confirm the exact Lync version
    Launch Lync, go to Help > About Microsoft Lync, or check the installed version in Programs and Features
    Affected if The version shown is 2010 (version 4.0.x) rather than a newer version such as 2013, 2016, or 2021
  3. Locate .ocsmeet meeting files on the system
    Use File Explorer or run 'Get-ChildItem -Path C:\Users -Recurse -Filter *.ocsmeet -ErrorAction SilentlyContinue' to search for .ocsmeet files in user directories, shared folders, or download locations
    Affected if Any .ocsmeet files exist in directories where untrusted users could write files (shared drives, downloads folder, desktop)
  4. Inspect DLL files in directories containing .ocsmeet files
    Check each directory containing .ocsmeet files for unexpected or suspicious DLL files by listing all files with 'dir' or 'Get-ChildItem'
    Affected if Unexpected DLL files are present in directories that also contain .ocsmeet files, especially in shared or writable locations
  5. Identify if Lync is launched from directories with .ocsmeet files
    Observe or audit typical workflow: determine if users commonly open Lync by double-clicking .ocsmeet files, or if Lync is launched while the current working directory contains meeting files
    Affected if Users typically launch Lync while their working directory contains .ocsmeet files from shared or untrusted locations

A user is affected if Microsoft Lync 2010 (not newer versions) is installed and the user opens or launches Lync from directories containing .ocsmeet files that could be manipulated by local attackers.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft's security update for this vulnerability (MS12-037) and ensure users do not launch Lync from untrusted or shared network directories containing .ocsmeet files.

Recommended fix High confidence

Microsoft Teams or Skype for Business 2015/2016 (supported releases)

  1. 1. Verify the current Lync 2010 installation and confirm the vulnerable DLL loading behavior
  2. 2. Migrate from Microsoft Lync 2010 to Microsoft Teams or Skype for Business, as Lync 2010 reached end of support on April 10, 2018
  3. 3. Deploy Microsoft Teams as the recommended collaboration platform, which does not have this insecure library loading vulnerability
  4. 4. Remove or uninstall Lync 2010 client from all affected workstations after migration is complete
  5. 5. Ensure the new Teams or Skype for Business client is installed from trusted sources and digitally signed
Caveat Migration from Lync 2010 to Teams requires user training and may require infrastructure changes; legacy .ocsmeet meeting files will need to be converted to Teams format

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

Fix this in Lync Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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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-2012-1849 in production — separate from our analysis above.

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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
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