CVE-2024-26297

Executive Summary

CVE-2024-26297 is a critical command injection vulnerability in the Hewlett Packard Enterprise (HPE) ClearPass Policy Manager web-based management interface. An authenticated remote attacker can exploit this flaw to execute arbitrary commands as root on the underlying operating system, leading to a complete system compromise. The vulnerability carries a CVSS score of 7.2 (High), and while the EPSS score is currently 0.0%, the potential for exploitation is significant given the privileged access it grants. No public proof-of-concept (PoC) or exploit code has been released, and no official patch is available at this time. This report provides a comprehensive technical analysis, detection strategies, and mitigation recommendations.

CVSS Breakdown & Threat Level

• CVSS Score: 7.2 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
• Attack Vector (AV): Network (N) – The vulnerability is exploitable remotely over the network.
• Attack Complexity (AC): Low (L) – No special conditions or complex attack sequences are required.
• Privileges Required (PR): High (H) – An attacker must have valid administrative credentials to the ClearPass web interface.
• User Interaction (UI): None (N) – No user interaction is required for exploitation.
• Scope (S): Unchanged (U) – The vulnerability does not affect resources beyond the affected component.
• Confidentiality (C): High (H) – Complete disclosure of all system data.
• Integrity (I): High (H) – Complete compromise of system integrity.
• Availability (A): High (H) – Full denial of service or system takeover.

Threat Level: High. While authentication is required, the impact is total system compromise. The lack of a patch makes this a significant risk for all HPE ClearPass deployments.

Deep Dive & Mechanics

The vulnerability resides in the ClearPass Policy Manager's web-based management interface. The application fails to properly sanitize user-supplied input before passing it to system commands. Specifically, certain parameters within the web interface are not validated or escaped, allowing an authenticated attacker to inject arbitrary operating system commands.

Attack Flow:

1. Authentication: The attacker must first obtain valid credentials for the ClearPass web interface (e.g., via phishing, credential stuffing, or insider threat).
2. Crafting Payload: The attacker identifies an input field (e.g., in a configuration page, diagnostic tool, or report generation) that is passed to a shell command. They inject command separators (e.g., ;, |, &&) followed by malicious commands.
3. Execution: The web server executes the crafted command with root privileges, allowing the attacker to run arbitrary code on the underlying host.
4. Post-Exploitation: The attacker can install backdoors, exfiltrate data, pivot to other network segments, or disrupt operations.

Root Cause: The vulnerability is a classic OS command injection (CWE-78). The application likely uses functions like system(), exec(), or Runtime.exec() in Java without proper input validation or use of safe APIs.

Vulnerable vs. Patched Code

Since no official patch is available, a direct code comparison is not possible. However, the vulnerable code pattern is typical of command injection flaws.

Vulnerable Code Example (Hypothetical Java):

String userInput = request.getParameter("hostname");
String command = "ping -c 4 " + userInput;
Process process = Runtime.getRuntime().exec(command);

Patched Code Example (Hypothetical):

String userInput = request.getParameter("hostname");
// Validate input: only allow alphanumeric and hyphens
if (!userInput.matches("[a-zA-Z0-9\\-]+")) {
    throw new IllegalArgumentException("Invalid input");
}
// Use a safe API or properly escape
List<String> command = new ArrayList<>();
command.add("ping");
command.add("-c");
command.add("4");
command.add(userInput);
ProcessBuilder pb = new ProcessBuilder(command);
Process process = pb.start();

The patched version uses input validation and ProcessBuilder to avoid shell interpretation.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Valid administrative credentials to the ClearPass web interface.
• Network access to the management interface (typically TCP/443 or TCP/8443).

Exploitation Steps:

1. Login: Authenticate to the ClearPass web interface.
2. Identify Vulnerable Endpoint: Use a web proxy (e.g., Burp Suite) to intercept requests. Look for parameters that are reflected in system commands (e.g., in diagnostic tools, backup/restore, or network testing features).
3. Inject Command: Modify a parameter to include a command injection payload. For example:

   original_param=127.0.0.1; id
   

4. Verify Execution: Observe the response for the output of the injected command (e.g., uid=0(root)).
5. Establish Persistence: Use the command execution to drop a web shell or SSH key.

Example Payload (URL-encoded):

hostname=127.0.0.1%3B%20whoami

Note: No public exploit code is available. The above is a generic methodology.

Blue Team (Defensive)

Detection & Response:

1. Monitor Authentication Logs: Look for unusual login patterns or multiple failed attempts.
2. Web Application Firewall (WAF): Deploy WAF rules to block common command injection patterns (e.g., ;, |, &&, $()).
3. Input Validation: Ensure all user inputs are validated against a whitelist of allowed characters.
4. Network Segmentation: Restrict access to the ClearPass management interface to trusted IPs only.
5. Endpoint Detection: Monitor for unexpected process execution (e.g., ping, nslookup, curl spawned by the web server process).

Indicators of Compromise (IOCs)

Network IOCs:

• Unusual outbound connections from the ClearPass server to external IPs (e.g., for data exfiltration or C2).
• HTTP requests containing command injection patterns (e.g., ;, |, &&, %3B).

Host IOCs:

• Unexpected files in /tmp/ or /var/tmp/ (e.g., web shells, scripts).
• New user accounts or SSH keys in /root/.ssh/authorized_keys.
• Processes running as root that were spawned by the web server (e.g., ping, nslookup, bash).
• Modified system binaries or configuration files.

Log IOCs:

• Web server logs showing requests with shell metacharacters.
• System logs (e.g., /var/log/messages) showing command execution from the web server user.

Detection Engineering

YARA Rule

rule CVE_2024_26297_ClearPass_CommandInjection {
    meta:
        description = "Detects potential command injection payloads targeting HPE ClearPass Policy Manager"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-26297"
        severity = "high"
    strings:
        $cmd1 = /[;&|`$()]/
        $cmd2 = /(ping|nslookup|curl|wget|bash|sh|python|perl)/
        $cmd3 = /(127\.0\.0\.1|localhost)/
    condition:
        any of ($cmd1) and any of ($cmd2) and any of ($cmd3)
}

Sigma Rule

title: HPE ClearPass Command Injection Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests with command injection patterns targeting ClearPass Policy Manager
author: Valters IT
date: 2024/10/27
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-26297
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - ';'
            - '|'
            - '&&'
            - '%3B'
            - '%7C'
    condition: selection
falsepositives:
    - Legitimate use of special characters in non-vulnerable parameters
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-26297 HPE ClearPass Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:";"; http_client_body; nocase; content:"|"; http_client_body; nocase; content:"&&"; http_client_body; nocase; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict Access: Limit network access to the ClearPass management interface to only trusted administrative IPs using firewall rules or VPN.
2. Enable Multi-Factor Authentication (MFA): Add an extra layer of security to prevent credential compromise.
3. Monitor Logs: Increase logging and monitoring for the ClearPass web interface and underlying host.
4. Apply Workarounds: If possible, disable or restrict access to vulnerable features (e.g., diagnostic tools, backup/restore).

Long-Term Fix:

• Apply Patch: Monitor HPE's security advisory page for an official patch. Apply as soon as it becomes available.
• Upgrade: Consider upgrading to a patched version of ClearPass Policy Manager once released.
• Code Review: If you have access to the source code, implement proper input validation and use safe APIs (e.g., ProcessBuilder instead of Runtime.exec()).

Valters IT Signature

This report was generated by Valters IT DevSecOps & CTI Expert System. For questions or further analysis, contact your Valters IT representative.