CVE-2025-7355

Executive Summary

CVE-2025-7355 is an Authorization Bypass Through User-Controlled Key vulnerability (CWE-639) in the Beefull App by Beefull Energy Technologies. This flaw allows an unauthenticated attacker to manipulate user-controlled identifiers (e.g., API keys, session tokens, or resource IDs) to access or modify resources belonging to other users without proper authorization. The vulnerability affects all versions of the Beefull App prior to 24.07.2025. With a CVSS score of 6.5 (Medium), the primary impact is on confidentiality, as an attacker can exploit trusted identifiers to bypass access controls. No public proof-of-concept (PoC) or exploit code has been released, and the vendor has not yet provided a patch. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk remains significant for organizations using the affected software.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network (AV:N) – The vulnerability can be exploited remotely.
• Attack Complexity: Low (AC:L) – No special conditions or complex steps required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No victim action required.
• Scope: Unchanged (S:U) – The vulnerable component and impacted component are the same.
• Confidentiality Impact: High (C:H) – Sensitive data can be accessed.
• Integrity Impact: None (I:N) – No data modification possible.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the lack of public exploit code and low EPSS score reduce immediate risk. However, the absence of a patch makes it a persistent threat.

Deep Dive & Mechanics

The vulnerability lies in how the Beefull App handles user-controlled keys (e.g., API tokens, session identifiers, or resource IDs). The application fails to validate that the key presented by a user belongs to that user, allowing an attacker to enumerate or guess valid keys and access resources of other users.

Root Cause: The application uses user-supplied identifiers (e.g., user_id, token, or resource_id) in backend requests without verifying ownership. For example, an API endpoint like /api/v1/user/data?user_id=123 may return data for user 123 without checking if the requester is authorized to view that data.

Attack Flow:

1. Attacker identifies an endpoint that accepts a user-controlled key (e.g., user_id, token, resource_id).
2. Attacker modifies the key to a different value (e.g., user_id=456).
3. The server processes the request and returns data belonging to the targeted user.
4. Attacker can iterate through keys to harvest sensitive information.

Impact: Unauthorized access to user data, including personal information, energy consumption data, and account details. This could lead to privacy breaches and further attacks.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

@app.route('/api/v1/user/data')
def get_user_data():
    user_id = request.args.get('user_id')
    # No authorization check
    data = db.query("SELECT * FROM users WHERE id = ?", user_id)
    return jsonify(data)

Patched Code (Conceptual):

@app.route('/api/v1/user/data')
def get_user_data():
    user_id = request.args.get('user_id')
    # Verify the authenticated user owns the requested resource
    current_user = get_current_user()
    if current_user.id != int(user_id):
        return jsonify({"error": "Unauthorized"}), 403
    data = db.query("SELECT * FROM users WHERE id = ?", user_id)
    return jsonify(data)

The patched version adds an authorization check to ensure the authenticated user can only access their own data.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to a Beefull App instance (version < 24.07.2025).
• Knowledge of an API endpoint that uses user-controlled keys.

Exploitation Steps:

1. Identify an endpoint like /api/v1/user/profile?user_id=1.
2. Send a request with a different user_id:

   curl -X GET "http://target.com/api/v1/user/profile?user_id=2"
   

3. If the response returns data for user 2, the vulnerability is confirmed.
4. Automate enumeration:

   for i in {1..100}; do
     curl -s "http://target.com/api/v1/user/profile?user_id=$i" | grep -q "error" || echo "User $i accessible"
   done
   

Note: No public exploit code is available; this is a conceptual demonstration.

Blue Team

Detection:

• Monitor for unusual patterns in API requests, especially sequential or rapid changes in user IDs.
• Alert on requests where user_id or similar parameters differ from the authenticated user's ID.

Prevention:

• Implement server-side authorization checks for all resource access.
• Use indirect object references (e.g., UUIDs) instead of sequential IDs.
• Enforce session-based authentication for all API endpoints.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Repeated API requests to endpoints like /api/v1/user/profile with varying user_id parameters.
  • Unusual traffic patterns from a single IP address enumerating user IDs.
• Log IOCs:
  • Log entries showing 403 Forbidden followed by 200 OK for the same endpoint with different parameters.
  • Multiple failed authorization attempts from the same source.
• File IOCs:
  • No specific file-based IOCs; the vulnerability is logic-based.

Detection Engineering

YARA Rule

rule CVE_2025_7355_Beefull_App_Auth_Bypass {
    meta:
        description = "Detects potential exploitation of CVE-2025-7355 in Beefull App logs"
        author = "Valters IT"
        date = "2025-07-25"
        reference = "CVE-2025-7355"
    strings:
        $api_endpoint = "/api/v1/user/" nocase
        $user_id_param = "user_id=" nocase
        $sequential_ids = /user_id=\d+/  // Matches numeric user IDs
    condition:
        $api_endpoint and $user_id_param and #sequential_ids > 5
}

Sigma Rule

title: CVE-2025-7355 - Beefull App Authorization Bypass
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects potential exploitation of CVE-2025-7355 via sequential user ID enumeration
author: Valters IT
date: 2025/07/25
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-7355
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-uri-query|contains: "/api/v1/user/"
        cs-uri-query|contains: "user_id="
    condition: selection
    timeframe: 5m
    aggregation:
        field: c-ip
        condition: gt 10
falsepositives:
    - Legitimate API usage with multiple users
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-7355 - Beefull App Authorization Bypass Attempt"; flow:to_server; content:"/api/v1/user/"; http_uri; content:"user_id="; http_uri; pcre:"/user_id=\d+/"; threshold: type both, track by_src, count 10, seconds 300; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the Beefull App from untrusted networks if possible.
2. Implement a Web Application Firewall (WAF) rule to block requests with suspicious user ID patterns.
3. Monitor logs for signs of exploitation.

Long-Term Fix:

• Apply the vendor patch once released (expected after 24.07.2025).
• If patching is not possible, modify the application code to enforce authorization checks on all user-controlled keys.
• Replace sequential IDs with cryptographically random tokens (e.g., UUIDs).

Workaround:

• Disable the vulnerable API endpoints if not essential.
• Implement additional authentication layers (e.g., API keys tied to sessions).

Valters IT Signature: This report is provided by Valters IT for educational and defensive purposes. Unauthorized exploitation of this vulnerability is illegal.