CVE-2024-9132: Arista NG Firewall Auth Bypass Vulnerability

CVE-2024-9132 Overview

CVE-2024-9132 is a critical code injection vulnerability affecting Arista NG Firewall that allows administrators to configure an insecure captive portal script. This vulnerability is classified under CWE-94 (Improper Control of Generation of Code), indicating that the firewall fails to properly validate or sanitize administrator-supplied captive portal script configurations, potentially enabling code injection attacks.

Critical Impact

This vulnerability allows attackers with network access to potentially achieve complete system compromise including unauthorized access to sensitive data, system modification, and service disruption on affected Arista NG Firewall appliances.

Affected Products

• Arista NG Firewall (all versions prior to patched release)

Discovery Timeline

• 2025-01-10 - CVE-2024-9132 published to NVD
• 2025-09-29 - Last updated in NVD database

Technical Details for CVE-2024-9132

Vulnerability Analysis

This vulnerability stems from improper input validation in the captive portal script configuration functionality within Arista NG Firewall. The captive portal feature, commonly used to redirect users to authentication or terms-of-service pages before granting network access, accepts administrator-configured scripts without adequate sanitization.

When an attacker can influence the configuration of these captive portal scripts—either through compromised administrator credentials, social engineering, or by exploiting another vulnerability to gain administrative access—they can inject malicious code that executes within the context of the firewall system. The attack can be launched remotely over the network without requiring user interaction, making it particularly dangerous in enterprise environments.

Root Cause

The root cause of CVE-2024-9132 is improper control of code generation (CWE-94) in the captive portal script configuration module. The Arista NG Firewall does not adequately validate, sanitize, or restrict the content that administrators can input when configuring captive portal scripts. This lack of input validation allows arbitrary code to be embedded within the configuration, which is then executed by the system when the captive portal functionality is triggered.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no privileges from the attacker's perspective at the exploitation stage once malicious configuration is in place. An attacker who gains administrative access to the firewall—through credential theft, brute force, or exploiting another vulnerability—can configure an insecure captive portal script containing malicious code.

When users connect to the network and trigger the captive portal, the injected code executes with the privileges of the firewall service. This could lead to:

• Complete compromise of the firewall appliance
• Exfiltration of network traffic and credentials
• Lateral movement to other network segments
• Persistent backdoor installation on the network perimeter

The vulnerability affects the confidentiality, integrity, and availability of the system, potentially allowing attackers to intercept sensitive data, modify firewall rules, or cause denial of service conditions.

Detection Methods for CVE-2024-9132

Indicators of Compromise

• Unexpected modifications to captive portal script configurations in the Arista NG Firewall administrative interface
• Unusual outbound connections originating from the firewall appliance
• Suspicious script content or encoded payloads within captive portal configuration files
• Unauthorized administrative login attempts or successful logins from unusual IP addresses
• Abnormal resource utilization on the firewall appliance

Detection Strategies

• Monitor Arista NG Firewall configuration changes through centralized logging and SIEM integration
• Implement file integrity monitoring on captive portal script configuration files
• Review administrative access logs for unauthorized or suspicious login activity
• Deploy network behavior analysis to detect unusual traffic patterns from firewall appliances
• Configure alerts for any captive portal configuration modifications

Monitoring Recommendations

• Enable comprehensive audit logging on all Arista NG Firewall administrative actions
• Implement real-time alerting for configuration changes to captive portal scripts
• Establish baseline network behavior for firewall appliances to detect anomalies
• Schedule regular security configuration reviews of captive portal settings

How to Mitigate CVE-2024-9132

Immediate Actions Required

• Review and audit all captive portal script configurations for unauthorized or suspicious content
• Restrict administrative access to the Arista NG Firewall to authorized personnel only
• Implement multi-factor authentication for all administrative access
• Apply the latest security patches from Arista as soon as available
• Monitor for any indicators of compromise on affected systems

Patch Information

Arista has released a security advisory addressing this vulnerability. Organizations should consult the Arista Security Advisory #0105 for specific patch information and update instructions. It is strongly recommended to apply the vendor-provided security update as the primary remediation measure.

Workarounds

• Limit captive portal script configuration access to a minimal number of trusted administrators
• Implement network segmentation to restrict access to the firewall management interface
• Deploy additional monitoring and logging for all administrative actions on the firewall
• Consider disabling captive portal functionality if not required for business operations until patches are applied
• Review and strengthen administrative account credentials and access controls

For detailed technical information and patch availability, refer to the official Arista Security Advisory #0105.