CVE-2025-30035

Executive Summary

CVE-2025-30035 is a critical authentication bypass vulnerability in CGM CLININET, a clinical information system. The flaw allows an unauthenticated attacker to fully bypass authentication by supplying only a valid username, without requiring a password or any other credentials. Once a session ID is obtained, the attacker can perform a session takeover, gaining access to the system with the privileges of the targeted user. This vulnerability poses a severe risk to patient data confidentiality, system integrity, and availability. No patch is currently available, and no public exploit code has been released.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (No vector provided)
• Attack Vector (AV): Network (likely)
• Attack Complexity (AC): Low (likely)
• Privileges Required (PR): None
• User Interaction (UI): None
• Scope (S): Changed (likely)
• Confidentiality (C): High
• Integrity (I): High
• Availability (A): High
• Threat Level: Critical

Deep Dive & Mechanics

The vulnerability resides in the authentication mechanism of CGM CLININET. The application fails to properly validate credentials, allowing an attacker to bypass the password verification step entirely. By simply providing a valid username, the system generates a session ID and grants access. This is a classic case of improper authentication (CWE-287). The attacker can then use this session ID to impersonate the user, accessing all data and functionality available to that account.

Vulnerable vs. Patched Code

No specific code snippets are available. The vulnerability is in the authentication logic. A patched version would require proper credential validation, such as:

# Vulnerable (pseudo-code)
def login(username):
    if user_exists(username):
        session = create_session(username)
        return session
    else:
        return "User not found"

# Patched (pseudo-code)
def login(username, password):
    if user_exists(username) and verify_password(username, password):
        session = create_session(username)
        return session
    else:
        return "Invalid credentials"

Exploitation & Lab Setup

Red Team

1. Reconnaissance: Identify CGM CLININET instances using Shodan dorks: ["CGM CLININET", "CLININET login"].
2. Username Enumeration: Use a list of common usernames (e.g., admin, doctor, nurse) or attempt to enumerate valid usernames via error messages.
3. Exploitation:
   • Send a POST request to the login endpoint with only the username parameter.
   • Example using curl:

     curl -X POST https://target.com/login -d "username=admin"
     

   • Capture the session ID from the response (e.g., in a cookie or JSON body).
4. Session Takeover: Use the obtained session ID to access authenticated endpoints.

   curl -X GET https://target.com/patient-records -H "Cookie: sessionid=STOLEN_SESSION_ID"
   

Blue Team

1. Detection: Monitor for login attempts without a password field.
2. Log Analysis: Look for successful logins where the password field is empty or missing.
3. Honeypot: Deploy fake user accounts to detect unauthorized access.
4. Network Segmentation: Isolate CGM CLININET from the internet and restrict access to trusted IPs.
5. Web Application Firewall (WAF): Create a rule to block requests missing the password parameter.

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST requests to /login with only username parameter.
  • Session IDs generated without a corresponding password validation.
• Logs:
  • Successful login events with empty or missing password fields.
  • Multiple login attempts with different usernames from the same IP.
• System:
  • Unusual access to patient records or administrative functions.
  • Session IDs being reused across different IP addresses.

Detection Engineering

YARA Rule

rule CVE_2025_30035_AuthBypass {
    meta:
        description = "Detects authentication bypass attempts for CVE-2025-30035"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-30035"
    strings:
        $login_endpoint = "/login"
        $username_param = "username="
        $no_password = "password="
    condition:
        $login_endpoint and $username_param and not $no_password
}

Sigma Rule

title: CGM CLININET Authentication Bypass Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests to CGM CLININET login without a password parameter.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/login'
        cs-uri-query|contains: 'username='
        cs-uri-query|not_contains: 'password='
    condition: selection
falsepositives:
    - Legitimate testing
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"CVE-2025-30035 CGM CLININET Authentication Bypass"; flow:to_server,established; content:"POST"; http_method; content:"/login"; http_uri; content:"username="; http_client_body; pcre:"/password=/"; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Disable remote access to CGM CLININET if possible. Implement network segmentation and restrict access to trusted IPs.
• Short-term: Apply any vendor-provided patch as soon as it becomes available. If no patch is available, implement a Web Application Firewall (WAF) rule to block requests missing the password parameter.
• Long-term: Conduct a full security audit of the authentication mechanism. Implement multi-factor authentication (MFA) and enforce strong password policies.
• Workaround: If patching is not possible, consider using a reverse proxy to add authentication before requests reach CGM CLININET.

Valters IT
Securing Digital Frontiers