CVE-2025-25182

Executive Summary

CVE-2025-25182 is a critical authentication bypass vulnerability in the Stroom data processing, storage, and analysis platform. The flaw allows an unauthenticated attacker to bypass authentication mechanisms when Stroom is configured with AWS Application Load Balancer (ALB) authentication and the application is accessible outside the ALB. This can lead to server-side request forgery (SSRF) against the AWS metadata endpoint, potentially resulting in code execution or privilege escalation. The vulnerability affects versions starting from 7.2-beta.53 up to, but not including, the fixed releases. The CVSS score is 9.4 (Critical), and no public proof-of-concept or exploit code is currently available. Immediate patching is strongly recommended.

CVSS Breakdown & Threat Level

• CVSS Score: 9.4 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network (AV:N) – The vulnerability can be exploited remotely.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: None (PR:N) – No authentication is needed.
• User Interaction: None (UI:N) – No user action is required.
• Scope: Unchanged (S:U) – The impact is confined to the vulnerable component.
• Confidentiality Impact: High (C:H) – Sensitive data, including AWS credentials, can be exposed.
• Integrity Impact: High (I:H) – An attacker can modify data or execute commands.
• Availability Impact: High (A:H) – The system can be disrupted or taken offline.

Deep Dive & Mechanics

The vulnerability arises from improper validation of authentication tokens when Stroom is deployed behind an AWS ALB. The ALB is configured to handle authentication, but if the application is also directly accessible (e.g., via a misconfigured security group or direct IP access), an attacker can bypass the ALB's authentication layer. This allows the attacker to send requests directly to Stroom without a valid token.

Once authenticated (or bypassed), the attacker can exploit the SSRF vulnerability by crafting requests that target the AWS metadata endpoint (http://169.254.169.254/latest/meta-data/). This endpoint provides instance metadata, including IAM role credentials. With these credentials, the attacker can escalate privileges to the AWS environment, potentially gaining access to other resources, executing code, or moving laterally.

The root cause is a missing or insufficient check on the source of the request (whether it came through the ALB or directly). The application trusts the ALB's authentication headers without verifying that the request actually passed through the ALB.

Vulnerable vs. Patched Code

The vulnerable code likely trusts the X-Forwarded-For or similar headers to determine if the request came through the ALB. The patched code adds a verification step, such as checking the source IP against the ALB's private IP range or validating a shared secret.

Vulnerable Code (Conceptual):

# Vulnerable: Trusts ALB headers without verification
def authenticate(request):
    if 'X-Amzn-Oidc-Identity' in request.headers:
        # Assume request came through ALB
        user = decode_token(request.headers['X-Amzn-Oidc-Identity'])
        return user
    else:
        return None

Patched Code (Conceptual):

# Patched: Verifies request came through ALB
def authenticate(request):
    # Check if request source IP is within ALB's private subnet
    if request.remote_addr in ALB_PRIVATE_IPS:
        if 'X-Amzn-Oidc-Identity' in request.headers:
            user = decode_token(request.headers['X-Amzn-Oidc-Identity'])
            return user
    return None

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy Stroom (v7.2-beta.53 or any vulnerable version) on an AWS EC2 instance.
2. Configure an ALB in front of Stroom with authentication enabled.
3. Ensure the EC2 instance's security group allows direct access to Stroom's port (e.g., 8080) from the internet (misconfiguration).
4. The attacker's machine should have network access to the EC2 instance's public IP.

Exploitation Steps:

1. Bypass Authentication: Send a direct HTTP request to the Stroom instance's public IP (not through the ALB). Since the ALB is bypassed, no authentication token is required.

   curl http://<stroom-public-ip>:8080/api/some-endpoint
   

2. SSRF to AWS Metadata: If the endpoint allows URL fetching, craft a request to the AWS metadata endpoint.

   curl http://<stroom-public-ip>:8080/api/fetch?url=http://169.254.169.254/latest/meta-data/iam/security-credentials/
   

3. Extract Credentials: Retrieve the IAM role name and then the credentials.

   curl http://<stroom-public-ip>:8080/api/fetch?url=http://169.254.169.254/latest/meta-data/iam/security-credentials/<role-name>
   

4. Privilege Escalation: Use the extracted AWS credentials to access other AWS services (e.g., S3, EC2, Lambda).

Blue Team

Detection:

• Monitor for direct access to Stroom ports that bypass the ALB.
• Alert on requests to the AWS metadata endpoint (169.254.169.254) from the Stroom application.
• Look for unusual IAM credential usage from the Stroom instance.

Hunting:

• Review ALB access logs for requests that do not have valid authentication headers.
• Check Stroom application logs for SSRF attempts (e.g., requests to internal IPs).
• Use AWS CloudTrail to detect API calls made with credentials that should not be used from the Stroom instance.

Indicators of Compromise (IOCs)

• Network:
  • Direct HTTP requests to Stroom's IP/port without going through the ALB.
  • Outbound requests from Stroom to http://169.254.169.254/.
  • Unusual outbound traffic to AWS API endpoints (e.g., sts.amazonaws.com, ec2.amazonaws.com).
• Logs:
  • Stroom logs showing requests to internal IPs (169.254.x.x).
  • ALB logs showing requests without X-Amzn-Oidc-Identity header.
• AWS:
  • IAM credentials from the Stroom instance used from an unexpected source IP.
  • Creation of new resources (e.g., EC2 instances, S3 buckets) from the Stroom instance.

Detection Engineering

YARA Rule

rule CVE_2025_25182_Stroom_Auth_Bypass {
    meta:
        description = "Detects Stroom authentication bypass attempts via direct access"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-25182"
    strings:
        $s1 = "X-Amzn-Oidc-Identity" ascii wide nocase
        $s2 = "169.254.169.254" ascii wide
        $s3 = "Stroom" ascii wide nocase
    condition:
        any of ($s*) and #s3 > 0
}

Sigma Rule

title: Stroom Authentication Bypass via Direct Access
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects direct HTTP requests to Stroom that bypass ALB authentication
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: stroom
detection:
    selection:
        c-uri|contains: "/api/"
        sc-status: 200
        cs-host: "<stroom-public-ip>"
    condition: selection
falsepositives:
    - Legitimate direct access if ALB is not used
level: critical

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET 8080 (msg:"CVE-2025-25182 Stroom Authentication Bypass Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/api/"; http_uri; content:!"X-Amzn-Oidc-Identity"; http_header_names; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade Stroom to versions 7.2.24, 7.3-beta.22, 7.4.4, or 7.5-beta.2 or later.
2. Network Segmentation: Ensure the Stroom instance is only accessible through the ALB. Restrict direct access via security groups or network ACLs.
3. IAM Hardening: Limit the IAM role attached to the Stroom instance to the minimum necessary permissions. Use AWS IAM policies to prevent access to sensitive resources.

Long-term Measures:

• Implement network monitoring to detect direct access attempts.
• Use AWS WAF to block requests that do not contain valid ALB authentication headers.
• Regularly review and update security group rules.
• Conduct penetration testing to identify similar misconfigurations.

Valters IT Signature: This report was generated by Valters IT DevSecOps & CTI Expert System. For questions, contact security@valters-it.com.