CVE-2024-38516

Executive Summary

CVE-2024-38516 is a high-severity information disclosure vulnerability in the Aimeos e-commerce HTML client component (ai-client-html). The flaw allows sensitive environment variables to be leaked through debug error logs. An attacker who gains access to these logs can extract credentials, API keys, database passwords, and other secrets, potentially leading to full system compromise. The vulnerability has been patched in versions 2024.04.7, 2023.10.15, 2022.10.13, and 2021.10.22. No public proof-of-concept or exploit code is available at this time.

Supply Chain & Package Security

This vulnerability affects the ai-client-html package, which is distributed via Composer (PHP). Organizations using Aimeos should immediately audit their dependency versions and update to the patched releases. The lack of a public exploit does not reduce the risk, as the vulnerability is trivial to exploit once log access is obtained.

CVSS Breakdown & Threat Level

• CVSS Score: 8.8 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

The high CVSS score reflects the ease of exploitation and the severe impact of leaked credentials. An unauthenticated attacker can trigger debug logging and then access the logs to obtain environment variables, which often contain secrets that enable lateral movement and privilege escalation.

Deep Dive & Mechanics

The vulnerability resides in the error handling and logging mechanism of ai-client-html. When an error occurs, the component logs debug information that includes the contents of environment variables. This is typically done to aid developers in troubleshooting, but the logs are not properly sanitized or access-controlled.

Root Cause: The ai-client-html component uses PHP's var_dump() or similar functions to output error context, which includes the $_ENV superglobal. In production environments, debug logging should be disabled, but the component fails to enforce this.

Attack Vector: An attacker can trigger an error by sending malformed requests or exploiting other minor bugs. The error is then logged to a file (e.g., error.log). If the attacker can access this log file (via directory traversal, misconfigured web server, or other means), they can read the environment variables.

Impact: Environment variables often contain:

• Database credentials (DB_HOST, DB_USER, DB_PASS)
• API keys (STRIPE_KEY, AWS_ACCESS_KEY_ID)
• Secret keys (APP_SECRET, ENCRYPTION_KEY)
• SMTP credentials (MAIL_HOST, MAIL_USER, MAIL_PASS)

With these, an attacker can pivot to other systems, exfiltrate data, or deploy malware.

Vulnerable vs. Patched Code

Vulnerable Code (ai-client-html < 2024.04.7):

// In error handler
public function handleError($errno, $errstr, $errfile, $errline) {
    $debugInfo = [
        'error' => $errstr,
        'file' => $errfile,
        'line' => $errline,
        'env' => $_ENV // <-- Sensitive data leaked
    ];
    error_log(json_encode($debugInfo));
}

Patched Code (ai-client-html >= 2024.04.7):

// In error handler
public function handleError($errno, $errstr, $errfile, $errline) {
    $debugInfo = [
        'error' => $errstr,
        'file' => $errfile,
        'line' => $errline,
        'env' => 'REDACTED' // <-- Sensitive data removed
    ];
    error_log(json_encode($debugInfo));
}

The patch replaces the actual environment variable values with a static string "REDACTED", preventing leakage.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Aimeos instance with vulnerable ai-client-html (version < 2024.04.7)
• Access to the web application (no authentication required)

Steps:

1. Trigger an error: Send a malformed request to the Aimeos application. For example, a request with an invalid parameter:

   curl -X GET "http://target.com/shop?invalid_param=test"
   

2. Access the error log: If the log file is accessible via the web (e.g., /var/log/error.log), download it:

   curl -X GET "http://target.com/var/log/error.log"
   

3. Extract environment variables: Parse the log file for $_ENV entries:

   grep -oP '"env":\{"[^}]+' error.log | sed 's/"env"://'
   

Alternative: If the log is not directly accessible, use directory traversal or LFI vulnerabilities to read it.

Blue Team

Detection:

• Monitor for requests that trigger errors (e.g., 500 status codes) followed by attempts to access log files.
• Alert on any access to /var/log/ or similar paths from the web.

Prevention:

• Ensure debug logging is disabled in production (APP_DEBUG=false).
• Restrict access to log files via web server configuration (e.g., deny all in .htaccess).
• Use a WAF to block requests containing suspicious patterns (e.g., invalid_param).

Hunting:

• Search for log entries containing "env":{ in centralized logging systems.
• Check for environment variable names in logs (e.g., DB_PASSWORD, API_KEY).

Indicators of Compromise (IOCs)

• Log entries containing: "env":{ followed by key-value pairs of environment variables.
• Network traffic: Requests to /var/log/error.log or similar paths.
• File system: Unauthorized access to log files (e.g., /var/log/, /storage/logs/).
• Behavioral: Multiple 500 errors from a single IP followed by log file access.

Detection Engineering

YARA Rule

rule CVE_2024_38516_Aimeos_Log_Leak {
    meta:
        description = "Detects Aimeos error logs containing environment variable leakage"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-38516"
    strings:
        $env_leak = /"env":\{"[A-Z_]+":/
        $error_log = /error_log\(/
    condition:
        $env_leak and $error_log
}

Sigma Rule

title: Aimeos Environment Variable Leakage in Error Logs
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects attempts to access Aimeos error logs containing environment variables
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem:
            - '/var/log/error.log'
            - '/storage/logs/*'
            - '*.log'
    condition: selection
falsepositives:
    - Legitimate debugging by administrators
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-38516 Aimeos Log Access Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/var/log/error.log"; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Update Aimeos: Upgrade ai-client-html to version 2024.04.7, 2023.10.15, 2022.10.13, or 2021.10.22 (depending on your branch).

   composer require aimeos/ai-client-html:^2024.04.7
   

2. Disable debug mode: Set APP_DEBUG=false in your .env file.
3. Restrict log access: Configure your web server to deny access to log directories.
   • Apache: <Directory /var/log/> Deny from all </Directory>
   • Nginx: location /var/log/ { deny all; }

Long-term Measures:

• Implement centralized logging with access controls.
• Regularly rotate and audit environment variables.
• Use a secrets manager (e.g., HashiCorp Vault) instead of environment variables for sensitive data.
• Conduct periodic security reviews of error handling code.

Valters IT