CVE-2025-13771

Executive Summary

CVE-2025-13771 is an Arbitrary File Read vulnerability discovered in the WebITR application developed by Uniong. This flaw allows an authenticated remote attacker to exploit a Relative Path Traversal (CWE-23) to download arbitrary system files from the server. The vulnerability is currently unpatched, and no official patch or advisory has been released by the vendor. The CVSS score is listed as 0.0, indicating incomplete scoring data, but the impact is assessed as high due to the potential for sensitive data exfiltration (e.g., configuration files, credentials, source code). No public proof-of-concept (PoC) or exploit code has been identified at this time.

Supply Chain & Package Security

This vulnerability does not affect any open-source package ecosystems (NPM, PyPI, Go, Ruby). It is a proprietary web application (WebITR) developed by Uniong. Organizations using WebITR should treat this as a critical supply chain risk due to the lack of vendor response.

CVSS Breakdown & Threat Level

The CVSS score is currently 0.0, which is likely a placeholder or incomplete assessment. Based on the vulnerability description, a reasonable CVSS v3.1 vector would be:

• Attack Vector (AV): Network (N) – The attack is performed over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): Low (L) – Authentication is required, but low-privileged users can exploit it.
• User Interaction (UI): None (N) – No user interaction is needed.
• Scope (S): Unchanged (U) – The vulnerable component and the affected resource are the same.
• Confidentiality (C): High (H) – Arbitrary file read can expose sensitive data.
• Integrity (I): None (N) – No file modification is possible.
• Availability (A): None (N) – No impact on availability.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Estimated Base Score: 6.5 (Medium)

Threat Level: High – The vulnerability allows reading arbitrary system files, which can lead to credential theft, source code disclosure, and further lateral movement.

Deep Dive & Mechanics

The vulnerability resides in the WebITR application, which is used for IT resource management. The application fails to properly sanitize user-supplied input when handling file download requests. An authenticated attacker can inject relative path traversal sequences (e.g., ../) into the file path parameter to navigate outside the intended web root directory.

Root Cause: The application does not validate or canonicalize the file path before serving the file. This allows an attacker to request files such as:

• /etc/passwd
• C:\Windows\win.ini
• Application configuration files containing database credentials
• Source code files

Attack Flow:

1. Attacker authenticates to WebITR (e.g., using default or stolen credentials).
2. Attacker identifies a file download endpoint (e.g., /download?file=report.pdf).
3. Attacker modifies the file parameter to include path traversal sequences: /download?file=../../../etc/passwd.
4. The server reads and returns the contents of /etc/passwd to the attacker.

Impact: Full disclosure of sensitive system files, leading to privilege escalation, lateral movement, or complete compromise of the application server.

Vulnerable vs. Patched Code

Since no patch is available, a comparison cannot be made. However, the vulnerable code likely resembles:

# Vulnerable Python-like pseudocode
@app.route('/download')
def download():
    filename = request.args.get('file')
    # No path validation
    with open(filename, 'r') as f:
        return f.read()

A patched version would include path canonicalization and validation:

# Patched Python-like pseudocode
import os

@app.route('/download')
def download():
    filename = request.args.get('file')
    # Canonicalize and restrict to a safe directory
    safe_dir = '/var/www/webitr/uploads/'
    full_path = os.path.normpath(os.path.join(safe_dir, filename))
    if not full_path.startswith(safe_dir):
        return "Access denied", 403
    with open(full_path, 'r') as f:
        return f.read()

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable instance of WebITR (if available) or simulate the vulnerability using a custom Python Flask app.
2. Obtain valid credentials (e.g., admin:admin).
3. Use the following curl command to exploit:

curl -u admin:admin "http://target.com/download?file=../../../etc/passwd"

Expected Output:

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
...

Advanced Exploitation:

• Read application configuration files to extract database credentials.
• Read source code to find additional vulnerabilities.
• Use path traversal to read SSH private keys (/home/user/.ssh/id_rsa).

Blue Team

Detection:

• Monitor for HTTP requests containing ../ or ..\\ in query parameters.
• Alert on requests to file download endpoints with unusual file extensions (e.g., .php, .py, .conf).
• Use the detection rules provided below.

Mitigation:

• Implement strict input validation and path canonicalization.
• Use a web application firewall (WAF) to block path traversal patterns.
• Restrict file download functionality to a whitelist of allowed files.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP GET requests with path traversal sequences in query parameters:
  • GET /download?file=../../../etc/passwd
  • GET /download?file=..\..\..\windows\win.ini
• Unusual file extensions in download requests (e.g., .php, .py, .conf, .env).

File System IOCs:

• Unexpected access to system files (e.g., /etc/passwd, /etc/shadow, web.config).
• Log entries showing file read attempts outside the web root.

Log IOCs:

• Web server logs showing 200 responses to path traversal requests.
• Application logs with errors related to file not found or permission denied.

Detection Engineering

YARA Rule

rule CVE_2025_13771_WebITR_Path_Traversal {
    meta:
        description = "Detects path traversal attempts targeting WebITR Arbitrary File Read vulnerability"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-13771"
    strings:
        $path_traversal = /\.\.\/|\.\.\\/
        $web_itr_endpoint = /\/download\?file=/ nocase
    condition:
        $web_itr_endpoint and $path_traversal
}

Sigma Rule

title: WebITR Path Traversal Attempt
id: 8f7a3b2c-1d4e-5f6a-7b8c-9d0e1f2a3b4c
status: experimental
description: Detects path traversal attempts in WebITR download requests
author: Valters IT
date: 2025-04-10
references:
    - CVE-2025-13771
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 
            - '../'
            - '..\\'
        cs-uri-query|startswith: '/download?file='
    condition: selection
falsepositives:
    - Legitimate use of relative paths in some applications (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-13771 WebITR Path Traversal Attempt";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"/download?file="; http_uri;
    content:"../"; http_uri;
    classtype:attempted-recon;
    sid:10000001;
    rev:1;
    reference:cve,2025-13771;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate the WebITR server from the internet if possible.
2. Implement a Web Application Firewall (WAF) rule to block path traversal patterns.
3. Restrict file download functionality to a whitelist of allowed files.
4. Monitor logs for exploitation attempts.

Long-term Fix:

• Since no vendor patch is available, consider replacing WebITR with a supported alternative.
• If source code is available, apply the patched code example provided in the "Vulnerable vs. Patched Code" section.
• Contact Uniong for an official patch or workaround.

Compensating Controls:

• Enforce strict file system permissions to limit the impact of file read.
• Use application-level input validation and output encoding.
• Implement network segmentation to limit lateral movement.

Valters IT signature: This report is provided for authorized security testing and defensive purposes only. Unauthorized exploitation of CVE-2025-13771 is illegal.