CVE-2021-33045: Dahuasecurity IPC-HUM7xxx Auth Bypass

CVE-2021-33045 Overview

CVE-2021-33045 is an identity authentication bypass vulnerability discovered in multiple Dahua security products during the login process. This critical flaw allows unauthenticated remote attackers to bypass device identity authentication by constructing malicious data packets, gaining complete unauthorized access to affected IP cameras, network video recorders (NVRs), and video intercom systems.

Critical Impact

This vulnerability enables complete authentication bypass on Dahua surveillance devices, allowing attackers to gain full administrative access without credentials. The vulnerability is actively exploited in the wild and listed in CISA's Known Exploited Vulnerabilities catalog.

Affected Products

• Dahua IPC-HUM7xxx Series IP Cameras (Firmware)
• Dahua IPC-HX3xxx Series IP Cameras (Firmware)
• Dahua IPC-HX5xxx Series IP Cameras (Firmware)
• Dahua NVR-1xxx, NVR-2xxx, NVR-4xxx, NVR-5xxx, NVR-6xx Series Network Video Recorders (Firmware)
• Dahua VTH-542xH Video Intercom Indoor Monitors (Firmware)
• Dahua VTO-65xxx, VTO-75x95x Video Intercom Outdoor Stations (Firmware)
• Dahua XVR-4x04, XVR-4x08, XVR-5x04, XVR-5x08, XVR-5x16, XVR-7x16, XVR-7x32 Series Digital Video Recorders (Firmware)

Discovery Timeline

• September 15, 2021 - CVE-2021-33045 published to NVD
• January 13, 2026 - Last updated in NVD database

Technical Details for CVE-2021-33045

Vulnerability Analysis

This authentication bypass vulnerability (CWE-287: Improper Authentication) exists in the login mechanism of affected Dahua devices. The flaw allows attackers to circumvent the normal authentication process by crafting specially constructed data packets that exploit weaknesses in how the device validates login requests.

The vulnerability is particularly dangerous because it requires no prior authentication or user interaction to exploit. An attacker with network access to the device's web interface or management port can craft malicious requests that bypass all authentication checks, gaining immediate administrative access to the surveillance system.

Once exploited, attackers gain full control over the compromised device, enabling them to view live camera feeds, access recorded footage, modify device configurations, disable recording functionality, or use the compromised device as a pivot point for lateral movement within the network. Given the sensitive nature of surveillance systems and their typical deployment in critical infrastructure, commercial facilities, and residential environments, the potential for privacy violations and security breaches is substantial.

Root Cause

The root cause of CVE-2021-33045 lies in improper authentication validation within the login process of affected Dahua firmware. The authentication mechanism fails to properly verify the legitimacy of login requests, allowing specially crafted packets to bypass the credential verification step entirely.

The vulnerability stems from inadequate input validation and improper session handling in the authentication workflow. Rather than requiring valid credentials before establishing an authenticated session, the flawed implementation allows attackers to manipulate request parameters in a way that tricks the device into granting access without proper credential verification.

Attack Vector

The attack is network-based and can be executed remotely by any attacker who has network connectivity to the vulnerable device's management interface. The exploitation requires:

1. Network access to the Dahua device (typically via HTTP/HTTPS on ports 80/443 or proprietary ports)
2. Crafting malicious authentication packets that exploit the validation bypass
3. Sending the crafted packets to the device's login endpoint

The attack does not require valid credentials, user interaction, or any special privileges. Devices exposed directly to the internet are at highest risk, though internal network attackers can also exploit this vulnerability against devices on local networks.

Technical details regarding the specific exploitation methodology have been published to Packet Storm Security and the Full Disclosure mailing list.

Detection Methods for CVE-2021-33045

Indicators of Compromise

• Unexpected administrative sessions or logins to Dahua devices without corresponding valid authentication events
• Anomalous network traffic patterns to Dahua device management ports (HTTP/HTTPS, proprietary protocols)
• Configuration changes on surveillance devices without authorized user activity
• Unauthorized access to recorded video footage or live feeds
• Newly created user accounts or modified access credentials on affected devices

Detection Strategies

• Monitor network traffic for malformed or unusual authentication requests to Dahua device endpoints
• Implement network intrusion detection rules targeting known exploitation patterns for CVE-2021-33045
• Audit device access logs for authentication anomalies, including successful logins without corresponding credential submissions
• Deploy honeypot Dahua devices to detect active exploitation attempts within your network

Monitoring Recommendations

• Isolate Dahua devices on dedicated network segments with strict firewall rules limiting management access
• Enable comprehensive logging on all Dahua devices and forward logs to a centralized SIEM for analysis
• Implement network behavior analysis to detect unusual traffic patterns to surveillance infrastructure
• Regularly audit device configurations and user accounts for unauthorized modifications

How to Mitigate CVE-2021-33045

Immediate Actions Required

• Apply firmware updates from Dahua immediately to all affected devices as detailed in the Dahua Security Advisory
• If patching is not immediately possible, restrict network access to device management interfaces using firewall rules
• Never expose Dahua device management interfaces directly to the internet
• Conduct an audit of all Dahua devices to identify any signs of compromise before and after patching
• Enable multi-factor authentication if supported by device firmware and network infrastructure

Patch Information

Dahua has released security patches addressing CVE-2021-33045 for all affected product lines. Detailed patch information, affected firmware versions, and updated firmware downloads are available through the official Dahua Cybersecurity Advisory.

Organizations should prioritize patching based on device exposure, with internet-facing and critical infrastructure devices receiving immediate attention. Given that this vulnerability is listed in CISA's Known Exploited Vulnerabilities Catalog, federal agencies and critical infrastructure operators may have mandatory remediation timelines.

Workarounds

• Implement strict network segmentation to isolate surveillance systems from general network traffic and the internet
• Deploy a VPN or jump host requirement for all remote administrative access to Dahua devices
• Configure host-based firewalls or access control lists to limit management interface access to authorized IP addresses only
• Disable unused network services and protocols on Dahua devices to reduce attack surface
• Monitor for exploitation attempts while awaiting patch deployment

# Example firewall rule to restrict Dahua device management access
# Only allow management access from trusted admin network
iptables -A INPUT -p tcp -s 10.0.100.0/24 --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -s 10.0.100.0/24 --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP