CVE-2021-4075
📋 TL;DR
CVE-2021-4075 is a Server-Side Request Forgery (SSRF) vulnerability in Snipe-IT that allows attackers to make the application send unauthorized requests to internal systems. This could lead to information disclosure or further attacks against internal infrastructure. All Snipe-IT installations using vulnerable versions are affected.
💻 Affected Systems
- Snipe-IT
📦 What is this software?
Snipe It by Snipeitapp
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access internal services, exfiltrate sensitive data, or pivot to attack other internal systems through the compromised Snipe-IT instance.
Likely Case
Information disclosure from internal services, potential access to metadata services, or scanning of internal network segments.
If Mitigated
Limited impact if network segmentation restricts Snipe-IT's outbound connections and internal services are properly secured.
🎯 Exploit Status
Exploitation requires authenticated access. The vulnerability is in the asset import functionality where URL validation is insufficient.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit 4612b9e711b3ff5d2bcddbec5b18866d25f8e34e and later versions
Vendor Advisory: https://github.com/snipe/snipe-it/commit/4612b9e711b3ff5d2bcddbec5b18866d25f8e34e
Restart Required: No
Instructions:
1. Update Snipe-IT to the latest version or at least commit 4612b9e711b3ff5d2bcddbec5b18866d25f8e34e. 2. Apply the patch that improves URL validation in the asset import functionality. 3. Verify the fix by testing the vulnerable endpoint.
🔧 Temporary Workarounds
Disable Asset Import Feature
allTemporarily disable the asset import functionality that contains the vulnerable URL validation.
Network Segmentation
linuxRestrict Snipe-IT's outbound network access to only necessary external services.
iptables -A OUTPUT -p tcp --dport 80 -j DROP
iptables -A OUTPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Implement strict network egress filtering to prevent Snipe-IT from accessing internal services
- Monitor and audit all outbound HTTP requests from the Snipe-IT application
🔍 How to Verify
Check if Vulnerable:
Check if your Snipe-IT version is before commit 4612b9e711b3ff5d2bcddbec5b18866d25f8e34e. Test the asset import functionality with SSRF payloads.Check Version:
git log --oneline -1Verify Fix Applied:
Verify the commit hash includes 4612b9e711b3ff5d2bcddbec5b18866d25f8e34e. Test that SSRF payloads in asset import are now properly rejected.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound HTTP requests from Snipe-IT to internal IP addresses
- Multiple failed asset import attempts with unusual URLs
Network Indicators:
- HTTP requests from Snipe-IT server to internal services (169.254.169.254, 10.x, 192.168.x, etc.)
- Unusual traffic patterns from Snipe-IT to non-standard ports
SIEM Query:
source="snipe-it-logs" AND (url CONTAINS "169.254.169.254" OR url CONTAINS "10." OR url CONTAINS "192.168.")