CVE-2020-27130
📋 TL;DR
CVE-2020-27130 is a path traversal vulnerability in Cisco Security Manager that allows unauthenticated remote attackers to download arbitrary files from affected devices. This occurs due to improper validation of directory traversal sequences in requests. Organizations using vulnerable versions of Cisco Security Manager are affected.
💻 Affected Systems
- Cisco Security Manager
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through theft of sensitive configuration files, credentials, and system files leading to further network penetration.
Likely Case
Exfiltration of sensitive configuration data, passwords, and system information enabling lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation and access controls prevent external access to vulnerable interfaces.
🎯 Exploit Status
Simple path traversal payloads can be used; multiple proof-of-concept examples exist publicly.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Cisco Security Manager 4.22 and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-csm-path-trav-NgeRnqgR
Restart Required: Yes
Instructions:
1. Download Cisco Security Manager 4.22 or later from Cisco Software Center. 2. Backup current configuration. 3. Install the update following Cisco's upgrade guide. 4. Restart the Cisco Security Manager service.
🔧 Temporary Workarounds
Network Access Control
allRestrict access to Cisco Security Manager web interface to trusted IP addresses only
Configure firewall rules to allow only specific source IPs to TCP ports used by Cisco Security Manager (default 443)
Disable Unnecessary Interfaces
windowsDisable web interface if not required for operations
Stop Cisco Security Manager web service if console/CLI management suffices
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Cisco Security Manager from untrusted networks
- Deploy web application firewall (WAF) with path traversal protection rules in front of the vulnerable interface
🔍 How to Verify
Check if Vulnerable:
Check Cisco Security Manager version via web interface (Help > About) or Windows Programs listCheck Version:
In Cisco Security Manager GUI: Help > About, or check installed programs in Windows Control PanelVerify Fix Applied:
Verify version is 4.22 or higher and test path traversal attempts return proper error responses📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing ../ sequences to Cisco Security Manager endpoints
- Unusual file access patterns from external IPs
Network Indicators:
- Multiple failed path traversal attempts from single source
- Unusual outbound data transfers following traversal attempts
SIEM Query:
source="csm_logs" AND ("../" OR "..\" OR "%2e%2e%2f") AND status=200