CVE-2026-29115

Executive Summary

CVE-2026-29115 is a denial-of-service (DoS) vulnerability affecting certain Dahua products. An authenticated remote attacker can send a specially crafted packet, triggering an exception that causes the system to reboot unexpectedly. This can lead to service disruption, impacting surveillance operations and potentially causing data loss or security gaps. The vulnerability has a CVSS score of 0.0 (unscored) and no public exploit or patch details are available at this time. The attack vector is network-based, requires authentication, and has low complexity.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unscored)
• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): Low (L) – authenticated attacker
• User Interaction (UI): None (N)
• Scope (S): Unchanged (U)
• Confidentiality (C): None (N)
• Integrity (I): None (N)
• Availability (A): High (H) – system reboot
• Threat Level: Medium (due to DoS impact and authenticated requirement)

Deep Dive & Mechanics

The vulnerability resides in the packet processing logic of Dahua products. When an authenticated attacker sends a specially crafted network packet, the system fails to handle an exception properly, leading to an unhandled error that triggers a system reboot. This is a classic uncaught exception (CWE-248) that results in a denial of service.

The attack is performed over the network, likely targeting a specific service or API endpoint. The crafted packet causes a state where the software enters an invalid condition, and instead of gracefully handling the error, the system crashes and reboots. This can be exploited repeatedly to maintain a denial-of-service condition.

Vulnerable vs. Patched Code

No specific code or patch details are available. The vulnerability is present in some Dahua products, but the exact version ranges and affected components are unknown. Without a patch, the vulnerable code remains unpatched.

Exploitation & Lab Setup

Red Team

1. Reconnaissance: Identify Dahua devices on the network using Shodan dorks or network scanning (e.g., nmap -p 80,443,554,37777 <target>).
2. Authentication: Obtain valid credentials (e.g., default passwords, brute-force, or phishing).
3. Craft Packet: Use a tool like Scapy or a custom Python script to send a specially crafted packet to the target service.
4. Trigger DoS: Send the packet repeatedly to cause the system to reboot, disrupting service.

Example Python script (conceptual):

import socket

target_ip = "192.168.1.100"
target_port = 37777  # Example Dahua port

# Craft a malicious packet (placeholder)
malicious_packet = b"\x00" * 100  # Replace with actual crafted payload

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_ip, target_port))
sock.send(malicious_packet)
sock.close()

Blue Team

1. Monitor Network Traffic: Look for anomalous packets targeting Dahua services (e.g., port 37777, 554, 80).
2. Implement Rate Limiting: Limit the number of connections per source IP to prevent repeated attacks.
3. Enable Logging: Ensure detailed logging of all authentication attempts and packet anomalies.
4. Use IDS/IPS: Deploy Suricata or Snort rules to detect and block malicious packets.
5. Patch Management: Monitor Dahua’s official channels for patches and apply them immediately.

Indicators of Compromise (IOCs)

• Network Traffic: Unusual packets to Dahua ports (37777, 554, 80, 443) with malformed or unexpected payloads.
• System Logs: Repeated unexpected reboots or crash logs indicating an unhandled exception.
• Authentication Logs: Multiple failed or successful authentication attempts from a single source before the DoS event.
• File Hashes: No specific file hashes available.

Detection Engineering

YARA Rule

rule CVE_2026_29115_Dahua_DoS {
    meta:
        description = "Detects packets targeting Dahua DoS vulnerability"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2026-29115"
    strings:
        $s1 = { 00 00 00 00 }  // Placeholder for malicious pattern
        $s2 = "Dahua" nocase
    condition:
        $s2 and #s1 > 5
}

Sigma Rule

title: CVE-2026-29115 Dahua DoS Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects network packets targeting Dahua DoS vulnerability
author: Valters IT
logsource:
    category: network_connection
    product: suricata
detection:
    selection:
        dest_port:
            - 37777
            - 554
            - 80
        payload|contains: "00"  # Placeholder for malicious pattern
    condition: selection
falsepositives:
    - Legitimate Dahua traffic
level: high

Suricata Rule

alert tcp $EXTERNAL_NET any -> $HOME_NET 37777 (msg:"CVE-2026-29115 Dahua DoS Attempt"; flow:to_server,established; content:"|00 00 00 00|"; depth:100; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

1. Apply Patches: Check Dahua’s official website for firmware updates addressing CVE-2026-29115.
2. Network Segmentation: Isolate Dahua devices on a separate VLAN with strict access controls.
3. Disable Unused Services: Turn off unnecessary services and ports on Dahua devices.
4. Use Strong Authentication: Enforce strong passwords and multi-factor authentication where possible.
5. Monitor Logs: Regularly review system logs for signs of exploitation.
6. Implement IDS/IPS: Deploy the provided Suricata rule to detect and block malicious packets.

Valters IT
DevSecOps & Cyber Threat Intelligence