Dahua IP Camera and NVR Authentication Bypass Vulnerability (CVE-2021-33045) Security Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTCertain Dahua IP cameras, NVRs, XVRs, and thermal cameras
Attackers can bypass identity authentication during the login process by sending crafted malicious packets, gaining full administrative control
Immediately apply the latest firmware updates from the vendor and restrict direct internet access to the devices
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Download and apply the latest secure firmware version corresponding to your device model from the official Dahua Support website. If CLI access is available, verify the system status using the following commands:
# 1. Check current system information and firmware version
show system info
# 2. Apply the official firmware update via the recommended vendor utility or Web GUI2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, isolate the devices from the public internet. Implement strict firewall rules to restrict access to the device's management ports (e.g., TCP 80, 443, 37777) only to trusted administrative IP addresses.
# Restrict access to Dahua service port (e.g., 37777) using iptables
# Allow only trusted admin IP (e.g., 192.168.10.50) and drop all other traffic
iptables -A INPUT -p tcp -s 192.168.10.50 --dport 37777 -j ACCEPT
iptables -A INPUT -p tcp --dport 37777 -j DROP3. Log Audit & IoC Verification Commands
Monitor network traffic for anomalous login attempts or patterns associated with authentication bypass exploits. Use the following command to capture and inspect traffic on the service port:
# Monitor incoming traffic on the default Dahua service port for suspicious payloads
tcpdump -i eth0 -vv -X 'tcp port 37777'Stop Exposing VPN Ports to the Internet — Switch to Zero-Trust Access
Eliminate public-facing VPN concentrators and firewall management ports with identity-first Zero-Trust Network Access.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-33045) is a critical authentication bypass flaw (CWE-287) residing in the login authentication mechanism of various Dahua devices. The root cause lies in the insufficient validation of incoming authentication data packets during the login sequence, allowing an attacker to establish an authenticated session without providing valid credentials.
2. Exploitation Mechanics & Attack Scenario
An attacker can exploit this vulnerability by constructing and transmitting specially crafted network packets to the device's service port (typically TCP port 37777). These malicious packets contain specific parameters designed to bypass or trick the authentication validation logic. The device's firmware processes these packets and incorrectly treats the connection as a successfully authenticated session, granting the attacker administrative access to the web interface or API.
3. Infrastructure & Business Impact
With a CVSS score of 9.8 (Critical) and its inclusion in the CISA KEV (Known Exploited Vulnerabilities) catalog, this vulnerability poses an immediate threat as it is actively exploited in the wild. Successful exploitation allows unauthorized actors to hijack video feeds, alter device configurations, upload malicious firmware, or use the compromised IoT device as a pivot point to compromise the internal corporate network.
Official Vendor Advisories & References
The identity authentication bypass vulnerability found in some Dahua products during the login process. Attackers can bypass device identity authentication by constructing malicious data packets.
Frequently Asked SecOps Questions (CVE-2021-33045)
FAQQ1. How critical is CVE-2021-33045 and is it actively exploited in the wild?
CVE-2021-33045 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 99.6%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-33045?
Primary impacted vendors include dahua across ip camera, thermal camera, nvr, xv. Scope summary: Select Dahua IP cameras, NVRs, XVRs, and thermal cameras (refer to the official Dahua security advisory for the complete list of affected models and firmware versions)
Q3. What temporary mitigations or workarounds exist for CVE-2021-33045 before patching?
[Mitigation] Immediately apply the latest firmware updates from the vendor and restrict direct internet access to the devices Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2021-33045
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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