CVE-2025-34211

Executive Summary

CVE-2025-34211 exposes a critical cryptographic failure in Vasion Print (formerly PrinterLogic) Virtual Appliance. A hardcoded, identical private SSL key and certificate for the hostname pl-local.com are stored in cleartext within the appliance. This key is used to terminate TLS on ports 80/443. Any attacker with container-level access can extract the key, enabling decryption of TLS traffic, man-in-the-middle attacks, and certificate forgery. Because the key is identical across all deployments, a single compromise affects every Vasion Print installation. The vendor has identified this as V-2024-025.

CVSS Breakdown & Threat Level

CVSS Score: 9.8 (Critical) Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack Vector (AV): Network – The key can be extracted remotely if container access is achieved.
• Attack Complexity (AC): Low – The key is stored in cleartext and easily readable.
• Privileges Required (PR): None – No authentication needed to exploit after gaining container access.
• User Interaction (UI): None – No user action required.
• Scope (S): Unchanged – The vulnerable component is the appliance itself.
• Confidentiality (C): High – TLS traffic, including credentials, can be decrypted.
• Integrity (I): High – Attackers can forge certificates and impersonate the appliance.
• Availability (A): High – Full control over the appliance can lead to denial of service.

Threat Level: Critical. The hardcoded key undermines all TLS protections, allowing complete compromise of the appliance and its communications.

Deep Dive & Mechanics

The vulnerability stems from a hardcoded SSL private key and certificate for the hostname pl-local.com. This key is embedded in the appliance’s filesystem in cleartext and is identical across all Vasion Print deployments. The key is used to terminate TLS connections on ports 80 and 443.

Attack Flow:

1. Gain Container Access: The attacker must first achieve container-level access to the appliance. This could be via another vulnerability (e.g., RCE, file inclusion) or misconfiguration (e.g., exposed Docker socket).
2. Extract Key: The attacker reads the private key file from the filesystem (e.g., /etc/ssl/private/pl-local.key).
3. Decrypt Traffic: With the private key, the attacker can decrypt any captured TLS traffic to/from the appliance.
4. MITM Attack: The attacker can intercept and modify traffic between users and the appliance.
5. Certificate Forgery: The attacker can forge TLS certificates for pl-local.com, impersonating the appliance’s web UI to steal credentials.

The key is identical across all installations, meaning a single extraction compromises the entire Vasion Print ecosystem.

Vulnerable vs. Patched Code

Vulnerable Code (Pre-22.0.1049 / Pre-20.0.2786): The private key and certificate are stored in cleartext files within the appliance. Example path:

/etc/ssl/private/pl-local.key
/etc/ssl/certs/pl-local.crt

Patched Code (22.0.1049+ / 20.0.2786+): The vendor has removed the hardcoded key and now generates unique, per-installation certificates during initial setup. The key is stored securely (e.g., encrypted at rest) and is not identical across deployments.

Detection of Vulnerable Version: Check the version of the Virtual Appliance Host or Application. If below the patched versions, the appliance is vulnerable.

Exploitation & Lab Setup

Red Team

Objective: Extract the hardcoded private key and demonstrate TLS decryption.

Lab Setup:

1. Deploy a vulnerable Vasion Print appliance (version < 22.0.1049 for VA, < 20.0.2786 for SaaS).
2. Gain container-level access (e.g., via a known RCE or exposed API).

Exploitation Steps:

1. Access the container:

   docker exec -it <container_id> /bin/bash
   

2. Locate and extract the private key:

   cat /etc/ssl/private/pl-local.key
   

3. Capture TLS traffic (e.g., using tcpdump on the host):

   tcpdump -i eth0 port 443 -w capture.pcap
   

4. Decrypt the traffic using the extracted key:

   tshark -r capture.pcap -o ssl.keylog_file:pl-local.key -Y "tls" -T fields -e tls.handshake.type
   

5. Perform MITM: Use a tool like mitmproxy with the extracted key to intercept and modify traffic.

Blue Team

Detection:

• Monitor for unauthorized access to container filesystems (e.g., cat /etc/ssl/private/pl-local.key).
• Alert on any process reading the private key file outside of normal TLS termination.
• Use file integrity monitoring (FIM) on the key file path.

Hunting:

• Search for the hardcoded certificate fingerprint in network traffic.
• Look for unexpected TLS certificates claiming to be pl-local.com.

Mitigation:

• Immediately upgrade to the patched version.
• If patching is delayed, rotate the certificate and key, and restrict container access.

Indicators of Compromise (IOCs)

• File Path: /etc/ssl/private/pl-local.key (private key)
• File Path: /etc/ssl/certs/pl-local.crt (certificate)
• Certificate Subject: CN = pl-local.com
• Certificate Fingerprint (SHA-256): [REDACTED - unique per deployment but identical across all vulnerable versions]
• Network Traffic: TLS connections using the pl-local.com certificate.
• Process: Any process reading the key file outside of the web server (e.g., cat, openssl).

Detection Engineering

YARA Rule

rule CVE_2025_34211_Hardcoded_SSL_Key {
    meta:
        description = "Detects the hardcoded private SSL key for pl-local.com"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-34211"
    strings:
        $key_header = "-----BEGIN RSA PRIVATE KEY-----"
        $key_footer = "-----END RSA PRIVATE KEY-----"
        $pl_local = "pl-local.com"
    condition:
        $key_header and $key_footer and $pl_local
}

Sigma Rule

title: Detection of Hardcoded SSL Key Access
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects access to the hardcoded SSL private key file for pl-local.com
author: Valters IT
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/cat'
        CommandLine|contains: '/etc/ssl/private/pl-local.key'
    condition: selection
falsepositives:
    - Legitimate web server startup (rare)
level: high

Suricata Rule

alert tls any any -> any any (msg:"CVE-2025-34211 - Hardcoded pl-local.com Certificate Detected"; tls.cert_subject; content:"pl-local.com"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade: Update to Virtual Appliance Host version 22.0.1049 or later, or Application version 20.0.2786 or later.
2. Rotate Credentials: After patching, regenerate all TLS certificates and keys.
3. Revoke Old Certificates: If possible, revoke the old pl-local.com certificate from any trust stores.

Long-Term Mitigations:

• Implement file integrity monitoring (FIM) on critical SSL directories.
• Restrict container access using least privilege principles.
• Use network segmentation to limit exposure of the appliance.
• Conduct regular security audits for hardcoded secrets.

Workaround (if patching is delayed):

• Replace the hardcoded key with a unique, per-installation key.
• Restrict network access to the appliance to trusted IPs only.
• Monitor for any unauthorized access to the container.

Valters IT
DevSecOps & Cyber Threat Intelligence