Cloudanix VulnDB

CVE-2014-1823

None

CVSS

—

EPSS

51.1%

Published

Jun 11, 2014

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Attend

An old flaw in Microsoft Lync servers could let attackers run hidden code inside employees' browsers simply by getting them to click a specially made meeting link.

Exploitation
Remote Unauthenticated
Attacker needs
None
Complexity
Moderate
Impact
Data Tampering
Component
Application
Class
XSS
Remediation
Upgrade
Effort
Medium
Patch risk
Medium

What it actually does

The Web Components Server fails to sanitize meeting IDs in URLs, permitting injection of arbitrary HTML or JavaScript that executes in the context of other users' browsers.

Why it matters to the business

Attackers could hijack user sessions, steal meeting content or credentials, and disrupt internal communications without needing authenticated access.

How an attack unfolds

An attacker crafts a URL embedding a valid meeting ID plus malicious script, then distributes the link via email or chat; when a victim opens it through the Lync Web Components Server the script runs in their browser.

How to fix it

Apply the Microsoft security updates released for Lync Server 2010 and 2013; migrate to supported modern collaboration platforms; disable the Web Components Server if it is no longer required.

How to confirm the fix worked

Confirm patch installation via Microsoft Update catalog or server version checks; test that crafted meeting-ID URLs no longer execute script; review web-application firewall rules for input sanitization.

Typical attack path

  1. Identify a valid meeting ID from public or leaked Lync data
  2. Embed script payload inside the meeting-ID parameter of a crafted URL
  3. Send the malicious link to target users via email, instant message, or social engineering
  4. Victim clicks the link and the Web Components Server renders the page without sanitization
  5. Injected script executes, performing actions such as cookie theft or content exfiltration

How to detect it

Search web-server access logs for meeting-ID parameters containing HTML tags, script keywords, or unusually long encoded values; correlate with successful responses from the Web Components Server.

  • meetingId=.*<script
  • meetingId=.*javascript:
  • meetingId=.*onerror=
  • meetingId=.*%3Cscript

What your security team should do

  • Prioritize patching or decommissioning Lync Server 2010/2013 instances given their age and lack of ongoing support
  • Block or sanitize all meeting-ID parameters at any reverse-proxy or WAF layer
  • Audit logs for historical access to the Web Components Server from untrusted sources
  • Educate users to avoid clicking unsolicited Lync meeting links

The record

Cross-site scripting (XSS) vulnerability in the Web Components Server in Microsoft Lync Server 2010 and 2013 allows remote attackers to inject arbitrary web script or HTML via a crafted URL containing a valid meeting ID, aka "Lync Server Content Sanitization Vulnerability."

Affected packages

Ecosystem Package Introduced Fixed

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