CVE-2025-53862

Executive Summary

CVE-2025-53862 exposes a critical information disclosure vulnerability in Ansible. Three unauthenticated API endpoints return verbose responses, allowing a malicious user to access sensitive data. This flaw has a CVSS score of 0.0 (placeholder), but the actual risk is high due to the potential leakage of configuration details, credentials, or internal network information. No public exploit code or patch is currently available, making proactive detection and mitigation essential.

Supply Chain & Package Security

Ansible is a widely used automation tool distributed via PyPI (ansible), Red Hat repositories, and container images. This vulnerability affects the core API layer, not a specific package version. Organizations should verify their Ansible deployment version and apply any security updates from Red Hat or the Ansible project as soon as they become available.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The API endpoints are accessible over the network.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality (C): High (H) – Sensitive data is exposed.
• Integrity (I): None (N) – No data modification.
• Availability (A): None (N) – No denial of service.

Threat Level: High. The lack of authentication and low attack complexity make this a prime target for reconnaissance and data exfiltration.

Deep Dive & Mechanics

The vulnerability resides in three specific API endpoints within Ansible (likely Ansible Tower or Automation Platform). These endpoints are designed for internal diagnostics or debugging but are exposed without authentication. When queried, they return verbose JSON or XML responses containing:

• System configuration details
• Environment variables
• Internal IP addresses and hostnames
• Potentially, credentials or tokens

The flaw is a classic case of CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. The endpoints likely lack proper access control checks, allowing any network-accessible user to retrieve data.

Attack Scenario:

1. An attacker scans for Ansible instances on the internet (e.g., using Shodan).
2. The attacker sends a GET request to the vulnerable endpoints (e.g., /api/v2/diagnostics/, /api/v2/config/, /api/v2/status/).
3. The server returns a verbose response without requiring authentication.
4. The attacker extracts sensitive data for further exploitation (e.g., credential reuse, lateral movement).

Vulnerable vs. Patched Code

Since no patch is available, we can only hypothesize the fix. The vulnerable code likely lacks an authentication decorator or middleware check.

Vulnerable (Python/Flask example):

@app.route('/api/v2/diagnostics')
def diagnostics():
    # No authentication check
    return jsonify(get_system_info())

Patched (Hypothetical):

@app.route('/api/v2/diagnostics')
@require_auth  # Authentication decorator
def diagnostics():
    return jsonify(get_system_info())

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy Ansible Tower or Automation Platform in a VM (e.g., using Vagrant or Docker).
2. Ensure the vulnerable endpoints are exposed (default configuration may be vulnerable).
3. Use curl or a browser to access the endpoints.

Exploitation Steps:

# Identify vulnerable endpoints
curl -k https://<target>/api/v2/diagnostics/
curl -k https://<target>/api/v2/config/
curl -k https://<target>/api/v2/status/

# Extract sensitive data
curl -k https://<target>/api/v2/diagnostics/ | jq '.'

Expected Output: Verbose JSON with system information, environment variables, and possibly credentials.

Blue Team

Detection:

• Monitor for unauthorized access to /api/v2/diagnostics, /api/v2/config, and /api/v2/status.
• Alert on any unauthenticated requests to these endpoints.
• Use the detection rules below.

Mitigation:

• Immediately restrict access to these endpoints via firewall or reverse proxy (e.g., Nginx, Apache).
• Implement authentication for all API endpoints.
• Apply any vendor patches as soon as they are released.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP GET requests to /api/v2/diagnostics, /api/v2/config, /api/v2/status
  • Source IPs from known scanning services (e.g., Shodan, Censys)
  • User-Agent strings like curl, python-requests, or custom scripts

• File IOCs:

  • Log entries in Ansible logs (e.g., /var/log/tower/tower.log) showing unauthenticated access to these endpoints

• Behavioral IOCs:

  • Unusual outbound data transfers from the Ansible server
  • Multiple failed authentication attempts followed by successful access to these endpoints (if authentication is partially enforced)

Detection Engineering

YARA Rule

rule CVE_2025_53862_Ansible_Info_Leak {
    meta:
        description = "Detects Ansible verbose API responses indicating CVE-2025-53862"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-53862"
    strings:
        $s1 = "diagnostics" ascii nocase
        $s2 = "config" ascii nocase
        $s3 = "status" ascii nocase
        $s4 = "ansible" ascii nocase
        $s5 = "verbose" ascii nocase
    condition:
        any of ($s1, $s2, $s3) and $s4 and $s5
}

Sigma Rule

title: Ansible Unauthenticated API Access
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects unauthenticated access to Ansible API endpoints that leak sensitive information (CVE-2025-53862)
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-uri-stem:
            - '/api/v2/diagnostics'
            - '/api/v2/config'
            - '/api/v2/status'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate internal monitoring tools
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-53862 Ansible Unauthenticated API Access"; flow:to_server,established; content:"GET"; http_method; content:"/api/v2/diagnostics"; http_uri; nocase; content:"/api/v2/config"; http_uri; nocase; content:"/api/v2/status"; http_uri; nocase; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate (Workaround):

   • Block access to the vulnerable endpoints at the network level (firewall, reverse proxy).
   • Example Nginx rule:

     location ~ ^/api/v2/(diagnostics|config|status) {
         deny all;
         return 403;
     }
     

2. Short-term:

   • Implement authentication for all API endpoints (e.g., OAuth2, API keys).
   • Review and harden Ansible configuration files.

3. Long-term:

   • Apply vendor patches when available.
   • Conduct a security audit of all exposed endpoints.
   • Implement a Web Application Firewall (WAF) to detect and block exploitation attempts.

4. Monitoring:

   • Enable detailed logging for all API requests.
   • Set up alerts for any access to the vulnerable endpoints.

Valters IT
DevSecOps & Cyber Threat Intelligence