CVE-2024-20412: Cisco Firepower Auth Bypass Vulnerability

CVE-2024-20412 Overview

A vulnerability in Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 1000, 2100, 3100, and 4200 Series could allow an unauthenticated, local attacker to access an affected system using static credentials. This vulnerability is due to the presence of static accounts with hard-coded passwords on an affected system. An attacker could exploit this vulnerability by logging in to the CLI of an affected device with these credentials.

Critical Impact

A successful exploit could allow the attacker to access the affected system and retrieve sensitive information, perform limited troubleshooting actions, modify some configuration options, or render the device unable to boot to the operating system, requiring a reimage of the device.

Affected Products

• Cisco Firepower Threat Defense (FTD) Software versions 7.1.0 through 7.4.1.1
• Cisco Firepower 1000 Series (1010, 1020, 1030, 1040, 1120, 1140, 1150)
• Cisco Firepower 2100 Series (2110, 2120, 2130, 2140)
• Cisco Firepower 3100 Series (3105, 3110, 3120, 3130, 3140)
• Cisco Firepower 4200 Series (4215, 4225, 4245)

Discovery Timeline

• October 23, 2024 - CVE-2024-20412 published to NVD
• November 5, 2024 - Last updated in NVD database

Technical Details for CVE-2024-20412

Vulnerability Analysis

This vulnerability represents a severe instance of hardcoded credentials (CWE-798) and use of hard-coded passwords (CWE-259) in Cisco Firepower Threat Defense Software. The presence of static accounts with embedded credentials in the system firmware allows any attacker with local access to authenticate to the device CLI without requiring legitimate credentials.

The vulnerability affects multiple hardware platforms across the Firepower product line, including the 1000, 2100, 3100, and 4200 Series appliances. These devices are commonly deployed as perimeter security appliances, making unauthorized access particularly concerning from a network security perspective.

The impact of successful exploitation is three-fold: attackers can retrieve sensitive information from the device, modify certain configuration options that could weaken security posture, or potentially render the device unbootable—requiring a complete reimage to restore functionality.

Root Cause

The root cause of this vulnerability is the presence of static accounts with hard-coded passwords embedded in the Cisco Firepower Threat Defense Software. This is a fundamental security design flaw where credentials are compiled directly into the firmware rather than being dynamically generated or configured by administrators. Hard-coded credentials are particularly dangerous because they cannot be changed without a software update and may be discovered through reverse engineering or firmware analysis.

Attack Vector

This vulnerability requires local access to exploit. An attacker must have physical access to the device or access to the local network segment where the device's management interface is accessible. The attack process involves:

1. Gaining local access to the affected Cisco Firepower device
2. Connecting to the device's Command Line Interface (CLI)
3. Authenticating using the static, hard-coded credentials
4. Once authenticated, the attacker can retrieve sensitive configuration data, perform troubleshooting actions, modify configuration options, or potentially corrupt the boot process

The local attack vector means that while network-based exploitation is not directly possible, insider threats, physical security breaches, or compromised management network access could enable exploitation.

Detection Methods for CVE-2024-20412

Indicators of Compromise

• Unexpected or unauthorized CLI login sessions on Firepower devices
• Authentication events from unknown or unexpected local accounts
• Configuration changes that were not authorized by administrators
• Device boot failures or unexpected reimage requirements
• Anomalous access patterns to device management interfaces

Detection Strategies

• Monitor authentication logs on Firepower devices for login attempts using non-standard administrative accounts
• Implement alerting for successful CLI authentications outside of normal maintenance windows
• Review Firepower Management Center (FMC) audit logs for unauthorized configuration changes
• Deploy network monitoring to detect unusual traffic patterns to device management interfaces

Monitoring Recommendations

• Enable comprehensive logging on all affected Firepower appliances and forward logs to a centralized SIEM
• Configure alerts for any CLI access events, particularly those occurring outside business hours
• Regularly audit user accounts and authentication events on Firepower devices
• Monitor for device health anomalies that could indicate tampering or boot corruption attempts

How to Mitigate CVE-2024-20412

Immediate Actions Required

• Review the Cisco Security Advisory for detailed patch information and affected version lists
• Inventory all Cisco Firepower 1000, 2100, 3100, and 4200 Series devices in your environment
• Restrict physical and local network access to Firepower device management interfaces
• Implement network segmentation to limit access to device management planes
• Monitor for any suspicious authentication activity while planning upgrades

Patch Information

Cisco has released software updates that address this vulnerability. Organizations should upgrade to a fixed version of Cisco Firepower Threat Defense Software as specified in the Cisco Security Advisory. The affected software versions include FTD 7.1.0 through 7.1.0.3, 7.2.0 through 7.2.7, 7.3.0 through 7.3.1.2, and 7.4.0 through 7.4.1.1. Consult Cisco's advisory for the specific fixed release versions for your deployment.

Workarounds

• Cisco has not published workarounds that address this vulnerability directly
• Implement strict physical security controls to limit local access to affected devices
• Segment management network access using ACLs and firewall rules to restrict who can reach the device CLI
• Deploy monitoring and alerting for all CLI access attempts as a compensating control until patching is complete

# Example: Restrict management access via ACL (conceptual)
# Consult Cisco documentation for exact syntax
access-list MGMT-RESTRICT permit tcp host <admin-ip> host <firepower-mgmt-ip> eq ssh
access-list MGMT-RESTRICT deny tcp any host <firepower-mgmt-ip> eq ssh