CVE-2021-1448
📋 TL;DR
This vulnerability allows authenticated local attackers on Cisco Firepower Threat Defense devices running in multi-instance mode to execute arbitrary commands with root privileges. Attackers can exploit insufficient input validation in the CLI to escalate privileges and gain full control of the underlying operating system. Only devices configured for multi-instance mode are affected.
💻 Affected Systems
- Cisco Firepower Threat Defense (FTD) Software
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the firewall device, allowing attackers to intercept/modify network traffic, install persistent backdoors, pivot to internal networks, and disable security controls.
Likely Case
Privilege escalation from authenticated user to root, enabling configuration changes, data exfiltration, and lateral movement within the network.
If Mitigated
Limited impact if proper access controls restrict local authentication and multi-instance mode is not used.
🎯 Exploit Status
Requires authenticated local access. Exploitation involves crafting malicious command arguments to the vulnerable CLI command.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.4.0.15, 6.6.5.2, 6.7.0.2, or 7.0.0 and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-cmdinj-vWY5wqZT
Restart Required: Yes
Instructions:
1. Download appropriate FTD software version from Cisco Software Center. 2. Upload to FMC. 3. Deploy upgrade to affected FTD devices. 4. Reboot devices after upgrade completion.
🔧 Temporary Workarounds
Disable multi-instance mode
allConvert affected devices from multi-instance to single-instance mode to eliminate vulnerability.
configure manager delete
configure manager add <FMC_IP> <REG_KEY>
🧯 If You Can't Patch
- Restrict local access to trusted administrators only using RBAC and network segmentation.
- Monitor for suspicious CLI command execution and privilege escalation attempts.
🔍 How to Verify
Check if Vulnerable:
Check FTD version with 'show version' and verify if running in multi-instance mode with 'show managers'.Check Version:
show version | include VersionVerify Fix Applied:
Verify version is 6.4.0.15, 6.6.5.2, 6.7.0.2, or 7.0.0+ with 'show version' command.📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command execution patterns
- Privilege escalation attempts in system logs
- Unexpected process execution as root
Network Indicators:
- Anomalous outbound connections from FTD management interface
- Unexpected configuration changes
SIEM Query:
source="ftd_logs" AND (event_type="privilege_escalation" OR command="*injection*" OR user="root" AND action="execute")