CVE-2022-25481: ThinkPHP Information Disclosure Flaw

CVE-2022-25481 Overview

CVE-2022-25481 is an Information Disclosure vulnerability affecting ThinkPHP Framework v5.0.24. The framework was discovered to be configured without the PATHINFO parameter, which allows attackers to access all system environment parameters from index.php. This vulnerability enables remote attackers to extract sensitive configuration data and environment variables that could be leveraged for further attacks against the application or underlying infrastructure.

Critical Impact

Remote attackers can access sensitive system environment parameters without authentication, potentially exposing database credentials, API keys, and other confidential configuration data.

Affected Products

• ThinkPHP Framework v5.0.24
• Applications built on ThinkPHP v5.0.24 with default configurations
• Web servers hosting ThinkPHP applications with debugging mode enabled

Discovery Timeline

• 2022-03-21 - CVE-2022-25481 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-25481

Vulnerability Analysis

This vulnerability stems from an improper configuration in ThinkPHP Framework v5.0.24 where the PATHINFO parameter is not properly set, resulting in the exposure of system environment parameters through the index.php endpoint. When this misconfiguration exists, attackers can craft requests to the application's entry point to retrieve environment variables that should remain protected.

It's important to note that this vulnerability is disputed by a third party who argues that system environment exposure is an intended feature of the debugging mode. However, if debugging mode is inadvertently left enabled in production environments, this behavior represents a significant security risk as it can leak sensitive information including database connection strings, API credentials, and internal network configurations.

The vulnerability is classified under CWE-668 (Exposure of Resource to Wrong Sphere) and CWE-284 (Improper Access Control), reflecting the core issue of sensitive data being accessible to unauthorized parties.

Root Cause

The root cause of this vulnerability is the absence of the PATHINFO parameter configuration in ThinkPHP v5.0.24. When this parameter is not properly configured, the framework fails to properly restrict access to internal debugging information. Combined with debugging mode being enabled (which may be the default or accidentally left on in production), this allows the framework to expose system environment variables through the web-accessible index.php endpoint.

Attack Vector

The attack vector for CVE-2022-25481 is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by sending specially crafted HTTP requests directly to the index.php file of a vulnerable ThinkPHP application. The attack is straightforward and can be executed remotely, making it particularly dangerous for internet-facing applications.

The exploitation process involves accessing the application's entry point in a way that triggers the framework to reveal environment parameters. Since no special privileges or complex attack chains are required, the barrier to exploitation is low. Attackers can enumerate exposed environment variables to harvest credentials, internal paths, and configuration details that facilitate subsequent attacks.

For detailed technical information about the exploitation mechanism, refer to the GitHub InfoLeak Vulnerability Report.

Detection Methods for CVE-2022-25481

Indicators of Compromise

• Unusual HTTP requests to index.php with unexpected parameters or path patterns
• Access logs showing repeated requests attempting to retrieve environment variables
• Requests containing debugging-related parameters or paths targeting the application entry point
• Evidence of reconnaissance activity focused on framework identification and version enumeration

Detection Strategies

• Monitor web server access logs for suspicious requests to index.php with unusual query patterns
• Implement Web Application Firewall (WAF) rules to detect and block requests attempting to access debugging endpoints
• Deploy intrusion detection systems (IDS) with signatures for ThinkPHP information disclosure attacks
• Regularly scan applications using vulnerability scanners that can identify exposed debugging interfaces

Monitoring Recommendations

• Enable verbose logging on web servers hosting ThinkPHP applications to capture detailed request information
• Set up alerts for access patterns consistent with information gathering or reconnaissance activities
• Monitor for outbound connections that may indicate harvested credentials being tested or exfiltrated
• Implement file integrity monitoring on ThinkPHP configuration files to detect unauthorized changes to debugging settings

How to Mitigate CVE-2022-25481

Immediate Actions Required

• Verify that debugging mode is disabled in all production ThinkPHP installations
• Review and configure the PATHINFO parameter appropriately in the application configuration
• Audit environment variables for sensitive information that could be exposed
• Implement access controls to restrict access to the application's entry point from untrusted sources

Patch Information

ThinkPHP users should ensure that debugging mode is disabled in production environments by setting the appropriate configuration option. Review the official ThinkPHP documentation for guidance on securing framework configurations. If running v5.0.24 specifically, consider upgrading to a newer version where security configurations may be more robust by default.

For additional technical details and verification steps, consult the GitHub InfoLeak Vulnerability Report.

Workarounds

• Disable debugging mode in production by setting 'app_debug' => false in the application configuration
• Configure web server rules to restrict direct access to index.php debugging features
• Use environment variable management practices that don't expose sensitive values through the web application
• Implement network-level access controls to limit exposure of development or staging environments

# Configuration example - Disable debugging mode in ThinkPHP config/app.php
# Set app_debug to false for production environments
# 'app_debug' => false,

# Additionally, ensure environment files are not web-accessible
# Add to .htaccess or nginx configuration
# deny access to sensitive configuration files
# location ~ /\.(env|git) {
#     deny all;
# }