CVE-2024-52881

Executive Summary

CVE-2024-52881 exposes a critical security flaw in AudioCodes One Voice Operations Center (OVOC) versions prior to 8.4.582. The vulnerability stems from the use of a hard-coded cryptographic key, which allows an attacker with access to the topology file to decrypt sensitive data, including user passwords. This weakness undermines the confidentiality of stored credentials and can lead to unauthorized access to the OVOC system and potentially the broader voice network infrastructure.

Supply Chain & Package Security

This vulnerability is not related to an open-source package manager (NPM, PyPI, Go, Ruby). It is a proprietary software component from AudioCodes. The risk is introduced through the vendor's software distribution and deployment within an organization's voice operations environment.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating that a full vector has not been officially assigned by NVD at this time. However, based on the nature of the vulnerability, a reasonable assessment would be:

• Attack Vector (AV): Network (AV:N) – The attacker needs access to the topology file, which could be obtained over the network.
• Attack Complexity (AC): Low (AC:L) – The hard-coded key is static and publicly discoverable.
• Privileges Required (PR): Low (PR:L) – The attacker requires access to the topology file, which may be accessible to authenticated users or through other means.
• User Interaction (UI): None (UI:N) – No user action is required for exploitation.
• Scope (S): Unchanged (S:U) – The vulnerability does not change the scope of the affected component.
• Confidentiality (C): High (C:H) – Decrypted passwords lead to full credential disclosure.
• Integrity (I): High (I:H) – With credentials, an attacker can modify system configurations.
• Availability (A): High (A:H) – An attacker could disrupt voice operations.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Estimated Base Score: 8.8 (High)

Deep Dive & Mechanics

The vulnerability is rooted in the use of a hard-coded encryption key within the OVOC application. The topology file, which contains sensitive configuration data such as device credentials, is encrypted using this static key. An attacker who gains access to this file (e.g., through file inclusion, directory traversal, or by compromising a system with read access) can decrypt it offline using the known key.

The decryption process is straightforward: the attacker extracts the encrypted data from the topology file, applies the hard-coded key using the known algorithm (likely AES or a similar symmetric cipher), and retrieves plaintext passwords. This bypasses any authentication or authorization controls that would normally protect these credentials.

Vulnerable vs. Patched Code

Vulnerable Code (Pre-8.4.582): The application uses a hard-coded key defined in a configuration or source file. For example:

# Vulnerable: Hard-coded key
ENCRYPTION_KEY = b'ThisIsAHardCodedKey123'
def decrypt_password(encrypted_data):
    cipher = AES.new(ENCRYPTION_KEY, AES.MODE_ECB)
    return cipher.decrypt(encrypted_data)

Patched Code (8.4.582+): The patched version removes the hard-coded key and implements a secure key management system. For example:

# Patched: Key derived from secure storage or environment
import os
from cryptography.fernet import Fernet
ENCRYPTION_KEY = os.environ.get('OVOC_ENCRYPTION_KEY')
if not ENCRYPTION_KEY:
    raise Exception("Encryption key not configured")
def decrypt_password(encrypted_data):
    cipher = Fernet(ENCRYPTION_KEY)
    return cipher.decrypt(encrypted_data)

Exploitation & Lab Setup

Red Team (Offensive)

1. Reconnaissance: Identify OVOC instances using Shodan dorks or internal network scanning. Locate the topology file (e.g., topology.dat or config.xml).
2. Access Topology File: Exploit a file inclusion vulnerability, use stolen credentials, or leverage a misconfigured web server to download the file.
3. Decrypt Data: Use the known hard-coded key to decrypt the file. Example Python script:

from Crypto.Cipher import AES
import base64

# Hard-coded key (example)
key = b'ThisIsAHardCodedKey123'
cipher = AES.new(key, AES.MODE_ECB)

with open('topology.dat', 'rb') as f:
    encrypted_data = f.read()

decrypted = cipher.decrypt(encrypted_data)
print(decrypted.decode('utf-8', errors='ignore'))

4. Extract Credentials: Parse the decrypted output for usernames and passwords.
5. Lateral Movement: Use the extracted credentials to access other systems (e.g., VoIP gateways, management interfaces).

Blue Team (Defensive)

1. Detect Hard-Coded Key Usage: Monitor for processes that use known static keys. Use YARA rules to scan binaries for the key string.
2. Monitor Topology File Access: Set up file integrity monitoring (FIM) on the topology file path. Alert on any read or download attempts.
3. Network Segmentation: Restrict access to OVOC management interfaces and topology files to authorized admin networks only.
4. Credential Rotation: Immediately rotate all passwords stored in the topology file after patching.
5. Log Analysis: Review logs for unusual decryption attempts or access to the topology file from unexpected IPs.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (Example – replace with actual if known)
  • topology.dat: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Indicators:
  • Outbound connections from OVOC to unknown IPs on ports 22 (SSH) or 443 (HTTPS) after credential extraction.
• Process Indicators:
  • Unusual decryption processes (e.g., python decrypt.py or openssl enc -d).
• Registry/File System:
  • Presence of decrypted credential files (e.g., passwords.txt) in temporary directories.

Detection Engineering

YARA Rule

rule CVE_2024_52881_Hardcoded_Key
{
    meta:
        description = "Detects hard-coded encryption key used in AudioCodes OVOC"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-52881"
    strings:
        $key1 = "ThisIsAHardCodedKey123" ascii wide nocase
        $key2 = "OVOC_ENCRYPTION_KEY" ascii wide nocase
    condition:
        any of them
}

Sigma Rule

title: Detection of Hard-Coded Key Usage in AudioCodes OVOC
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects processes using the hard-coded encryption key from CVE-2024-52881
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            - 'ThisIsAHardCodedKey123'
            - 'OVOC_ENCRYPTION_KEY'
    condition: selection
falsepositives:
    - Legitimate patched versions may still reference the key in logs
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-52881 - Potential Credential Exfiltration from OVOC"; flow:to_server; content:"topology.dat"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Upgrade to AudioCodes OVOC version 8.4.582 or later. This is the only official patch.
2. Workaround: If patching is not immediately possible, restrict access to the topology file using strict file system permissions (e.g., chmod 600 on Linux, NTFS permissions on Windows).
3. Credential Reset: After patching, reset all passwords that were stored in the topology file.
4. Network Controls: Implement network segmentation to limit access to OVOC management interfaces.
5. Monitoring: Deploy the YARA, Sigma, and Suricata rules provided above to detect exploitation attempts.
6. Vendor Communication: Contact AudioCodes support for additional guidance if needed.

Valters IT
DevSecOps & Cyber Threat Intelligence