CVE-2020-16941
📋 TL;DR
Microsoft SharePoint Server discloses folder structure information when rendering specific web pages, allowing attackers to view script file paths. This affects organizations running vulnerable SharePoint Server versions. Attackers need access to affected SharePoint pages to exploit this vulnerability.
💻 Affected Systems
- Microsoft SharePoint Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could map internal SharePoint structure, identify sensitive script locations, and potentially chain with other vulnerabilities for further exploitation.
Likely Case
Information disclosure revealing internal folder paths and script organization, aiding reconnaissance for targeted attacks.
If Mitigated
Limited impact with proper access controls and network segmentation preventing unauthorized access to SharePoint pages.
🎯 Exploit Status
Exploitation requires access to affected SharePoint pages; no authentication bypass needed beyond page access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update for exact version
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16941
Restart Required: Yes
Instructions:
1. Download security update from Microsoft Update Catalog. 2. Apply update to SharePoint Server. 3. Restart SharePoint services or server as required.
🔧 Temporary Workarounds
Restrict SharePoint Page Access
windowsLimit access to affected SharePoint pages to authorized users only
🧯 If You Can't Patch
- Implement strict access controls to limit SharePoint page access to necessary users only
- Monitor SharePoint access logs for unusual patterns or unauthorized access attempts
🔍 How to Verify
Check if Vulnerable:
Check SharePoint Server version against Microsoft Security Update; test if folder paths are disclosed on specific pagesCheck Version:
Get-SPFarm | Select BuildVersion (PowerShell on SharePoint Server)Verify Fix Applied:
Verify SharePoint Server is updated to patched version; test that folder paths are no longer disclosed📡 Detection & Monitoring
Log Indicators:
- Unusual access patterns to SharePoint pages, especially from unauthorized users
Network Indicators:
- Requests to SharePoint pages that might trigger path disclosure
SIEM Query:
source="sharepoint" AND (event_type="page_access" OR url_contains="specific_vulnerable_page")