CVE-2023-5422
📋 TL;DR
This vulnerability in OTRS and OTRS Community Edition allows attackers to intercept email communications by using invalid or expired SSL/TLS certificates. The software fails to properly verify certificates when fetching email via POP3/IMAP or sending via SMTP, enabling man-in-the-middle attacks. Affected systems include OTRS versions 7.0.X before 7.0.47, 8.0.X before 8.0.37, and Community Edition 6.0.X through 6.0.34.
💻 Affected Systems
- OTRS
- OTRS Community Edition
📦 What is this software?
Otrs by Otrs
Otrs by Otrs
Otrs by Otrs
⚠️ Risk & Real-World Impact
Worst Case
Attackers intercept all email communications, steal sensitive data, inject malicious content, and impersonate legitimate email servers to compromise entire email infrastructure.
Likely Case
Selective interception of email communications containing sensitive information, credential theft, and business email compromise attacks.
If Mitigated
No impact if proper certificate validation is enforced and network segmentation prevents man-in-the-middle positioning.
🎯 Exploit Status
Requires man-in-the-middle positioning between OTRS and email servers. Attackers need to intercept network traffic and present invalid certificates.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: OTRS 7.0.47, 8.0.37; OTRS Community Edition 6.0.35
Vendor Advisory: https://otrs.com/release-notes/otrs-security-advisory-2023-10/
Restart Required: Yes
Instructions:
1. Backup your OTRS installation and database. 2. Download the patched version from the OTRS website. 3. Follow the OTRS upgrade documentation for your version. 4. Restart the OTRS services after upgrade. 5. Verify certificate validation is now enforced.
🔧 Temporary Workarounds
Disable SSL/TLS Email Operations
allConfigure OTRS to use plain text email connections instead of SSL/TLS, eliminating the vulnerability but reducing security.
Edit OTRS configuration files to set email protocols to non-SSL versions (e.g., use IMAP instead of IMAPS)
Network Segmentation
allIsolate OTRS servers from untrusted networks and implement strict network controls to prevent man-in-the-middle attacks.
Configure firewall rules to restrict OTRS email traffic to trusted email servers only
🧯 If You Can't Patch
- Implement strict network segmentation and monitor all email-related network traffic for anomalies
- Use VPN tunnels or dedicated secure connections between OTRS and email servers to prevent interception
🔍 How to Verify
Check if Vulnerable:
Check OTRS version via Admin interface or configuration files. If using affected versions with SSL/TLS email configured, system is vulnerable.Check Version:
Check OTRS System Configuration or run: otrs.CheckModules.pl --allVerify Fix Applied:
After patching, test email operations with invalid certificates - connections should fail. Verify version shows patched release.📡 Detection & Monitoring
Log Indicators:
- Failed SSL/TLS handshakes with invalid certificates that previously succeeded
- Unusual email connection patterns or sources
Network Indicators:
- Unencrypted email traffic if workaround applied
- SSL/TLS connections with invalid certificates to OTRS
SIEM Query:
Search for OTRS email module errors or successful connections with certificate validation warnings disabled