CVE-2020-3550
📋 TL;DR
This vulnerability allows authenticated remote attackers to perform directory traversal attacks on Cisco Firepower Management Center (FMC) and Firepower Threat Defense (FTD) software. Attackers can read or write arbitrary files on connected peer devices by exploiting insufficient input validation in the sfmgr daemon. Organizations using affected Cisco Firepower products are at risk.
💻 Affected Systems
- Cisco Firepower Management Center (FMC) Software
- Cisco Firepower Threat Defense (FTD) Software
📦 What is this software?
Secure Firewall Management Center by Cisco
Secure Firewall Management Center by Cisco
Secure Firewall Management Center by Cisco
Secure Firewall Management Center by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of connected peer devices, allowing attackers to read sensitive configuration files, write malicious files, or potentially execute arbitrary code on affected systems.
Likely Case
Unauthorized access to sensitive files on peer devices, potentially exposing configuration data, credentials, or other sensitive information that could facilitate further attacks.
If Mitigated
Limited impact with proper network segmentation and access controls, restricting the attacker's ability to reach vulnerable interfaces or access sensitive peer devices.
🎯 Exploit Status
Requires authenticated access but exploitation is straightforward once authentication is obtained
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple fixed versions available - see Cisco advisory for specific version mappings
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftdfmc-dirtrav-NW8XcuSB
Restart Required: Yes
Instructions:
1. Review Cisco advisory for specific fixed versions for your deployment. 2. Download appropriate patches from Cisco Software Center. 3. Apply patches following Cisco upgrade procedures. 4. Restart affected services or devices as required.
🔧 Temporary Workarounds
Restrict network access to sfmgr daemon
allLimit network access to the sfmgr daemon interface to only trusted management networks
Implement strict authentication controls
allEnforce strong authentication mechanisms and limit administrative access to only necessary personnel
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks using network segmentation
- Implement strict access controls and monitor for suspicious sfmgr command activity
🔍 How to Verify
Check if Vulnerable:
Check current software version against affected versions listed in Cisco advisoryCheck Version:
show version (on FTD) or System > Updates > Version Information (on FMC web interface)Verify Fix Applied:
Verify software version has been updated to a fixed version listed in Cisco advisory📡 Detection & Monitoring
Log Indicators:
- Unusual sfmgr command patterns
- Directory traversal attempts in sfmgr logs
- Access to files outside expected directories
Network Indicators:
- Unusual sfmgr traffic patterns
- Connection attempts to sfmgr from unauthorized sources
SIEM Query:
source="*sfmgr*" AND (path="../" OR path="..\\" OR command="*traversal*")