CVE-2025-53534

Executive Summary

CVE-2025-53534 is a critical vulnerability in RatPanel, a server operation and maintenance management panel, affecting versions 2.3.19 through 2.5.5. The vulnerability allows an attacker who obtains the backend login path (via weak default paths, brute-force cracking, etc.) to execute system commands or take over hosts managed by the panel without authentication. The root cause is a flaw in the CleanPath middleware from the github.com/go-chi/chi package, which fails to process r.URL.Path, leading to path misinterpretation and unauthorized access. This vulnerability is unpatched in affected versions, with a fix available in version 2.5.6.

Supply Chain & Package Security

RatPanel is a Go-based application. The vulnerability originates from the github.com/go-chi/chi package, specifically the CleanPath middleware. This middleware is intended to clean URLs but does not process r.URL.Path, allowing attackers to bypass authentication by manipulating URL paths. The supply chain risk is moderate, as the vulnerability is in a third-party dependency, but the impact is severe due to the potential for remote code execution and host takeover.

CVSS Breakdown & Threat Level

CVSS Score: 0.0 (Not officially assigned, but based on the description, the severity is critical) 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) Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Threat Level: Critical

Deep Dive & Mechanics

The vulnerability lies in the CleanPath middleware used by RatPanel. The middleware is designed to sanitize and clean URL paths to prevent path traversal and other attacks. However, it fails to process r.URL.Path, which is the raw path from the HTTP request. This oversight allows an attacker to craft a URL that bypasses authentication checks.

For example, if the backend login path is /admin/login, an attacker could use a path like /admin/login/../ or /admin/login%2f..%2f to access protected resources without authentication. The middleware does not normalize the path, so the application interprets the path incorrectly, granting unauthorized access.

Once the attacker gains access, they can exploit the panel's functionality to execute system commands or take over managed hosts. The exact mechanism for command execution is not detailed, but it likely involves abusing the panel's administrative features.

Vulnerable vs. Patched Code

Vulnerable Code (version 2.3.19 - 2.5.5):

// CleanPath middleware from go-chi/chi
func CleanPath(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // Path cleaning logic, but does not process r.URL.Path
        // This allows path misinterpretation
        next.ServeHTTP(w, r)
    })
}

Patched Code (version 2.5.6):

// Patched CleanPath middleware
func CleanPath(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // Process r.URL.Path to normalize and clean it
        r.URL.Path = path.Clean(r.URL.Path)
        next.ServeHTTP(w, r)
    })
}

The patch adds r.URL.Path = path.Clean(r.URL.Path) to normalize the path, preventing path traversal and unauthorized access.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to a vulnerable RatPanel instance (version 2.3.19 - 2.5.5)
• Knowledge of the backend login path (e.g., /admin/login)

Exploitation Steps:

1. Identify the backend login path (e.g., via Shodan dorks or brute-force).
2. Craft a URL to bypass authentication:

   http://target.com/admin/login/../protected/resource
   

   or URL-encoded:

   http://target.com/admin/login%2f..%2fprotected/resource
   

3. Access the protected resource without authentication.
4. Use the panel's administrative features to execute system commands or take over hosts.

Example Command Execution:

curl -X POST "http://target.com/admin/login/../cmd" -d "command=whoami"

Blue Team

Detection:

• Monitor for unusual URL patterns, especially those containing ../ or %2f..%2f.
• Log all access attempts to the backend login path and subsequent resources.
• Use the detection rules provided below.

Mitigation:

• Immediately upgrade to RatPanel version 2.5.6 or later.
• If upgrade is not possible, implement a Web Application Firewall (WAF) rule to block path traversal attempts.
• Restrict access to the backend login path using IP whitelisting or VPN.

Indicators of Compromise (IOCs)

• URL Patterns: Requests containing ../ or %2f..%2f in the path.
• Access Logs: Unauthorized access to protected resources after a login path request.
• System Commands: Execution of unexpected commands (e.g., whoami, id, cat /etc/passwd).
• Network Traffic: Outbound connections from the RatPanel server to unknown IPs (indicating command and control).

Detection Engineering

YARA Rule

rule CVE_2025_53534_RatPanel_PathTraversal {
    meta:
        description = "Detects path traversal attempts targeting RatPanel CVE-2025-53534"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-53534"
    strings:
        $path_traversal1 = "../" ascii wide
        $path_traversal2 = "%2f..%2f" ascii wide
        $path_traversal3 = "/../" ascii wide
        $path_traversal4 = "/%2f..%2f" ascii wide
    condition:
        any of them
}

Sigma Rule

title: CVE-2025-53534 RatPanel Path Traversal Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects path traversal attempts in HTTP requests targeting RatPanel
author: Valters IT
date: 2025-01-01
references:
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-53534
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-uri-query|contains:
            - '../'
            - '%2f..%2f'
            - '/../'
            - '/%2f..%2f'
    condition: selection
falsepositives:
    - Legitimate use of path traversal in application logic (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-53534 RatPanel Path Traversal Attempt"; flow:to_server,established; content:"../"; http_uri; nocase; sid:1000001; rev:1;)
alert http any any -> any any (msg:"CVE-2025-53534 RatPanel Path Traversal Attempt (URL-encoded)"; flow:to_server,established; content:"%2f..%2f"; http_uri; nocase; sid:1000002; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade RatPanel to version 2.5.6 or later.
2. If upgrade is not possible, apply a WAF rule to block path traversal patterns.
3. Restrict access to the backend login path using IP whitelisting or VPN.

Long-term Measures:

• Regularly update all dependencies, including github.com/go-chi/chi.
• Implement input validation and path normalization in all middleware.
• Conduct security audits and penetration testing on the application.

Valters IT Signature

This report was generated by Valters IT Cyber Threat Intelligence. For more information, visit https://valters.it