CriticalCVE-2021-33044

    Dahua IP Camera Authentication Bypass Vulnerability (CVE-2021-33044)

    Published In CISA KEV since Sources: pwn.watch, SingCERT, CVE.org

    What is affected, what to do

    This vulnerability allows an attacker to bypass authentication on Dahua IP cameras by crafting malicious data packets, leading to full control over the device. It is actively exploited in the wild, as confirmed by its inclusion in the CISA KEV list. Affected products include specific firmware versions of Dahua IP cameras such as ipc-hum7xxx, ipc-hx3xxx, ipc-hx5xxx, sd1a1, sd22, sd49, sd50, and sd52c. Immediate patching to the latest firmware versions is crucial to mitigate this security risk.

    The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Some Dahua IP Camera, Video Intercom, PTZ Dome Camera, Thermal Camera devices eq Dahua IP Camera devices IPC-HX3XXX, IPC-HX5XXX, and IPC-HUM7XXX, Video Intercom devices VTO75X95X, VTO65XXX, and VTH542XH, PTZ D..Dahua IP Camera devices IPC-HX3XXX, IPC-HX5XXX, and IPC-HUM7XXX, Video Intercom devices VTO75X95X, VTO65XXX, and VTH542XH, PTZ D

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    Metrics

    9.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: pwn.watch, SingCERT, CVE.org

    99.99 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.98

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    228.97 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploited
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    9.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    9.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    99.99 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    99.98
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 5 September 2024
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-287

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw is network-reachable, pre-authentication and yields full device takeover — ticking every box for mass exploitation by IoT botnets (Mirai derivatives and successors). Cameras are typically online 24/7, rarely patched, and often perimeter-exposed, which places this CVE among the most likely to be exploited in the whole KEV catalogue. For NIS2 and KRITIS operators the priority is maximum even without a ransomware flag: hijacked cameras provide live footage of access points (feeding social engineering and physical reconnaissance) and serve as a pivot into internal OT/IT networks. Prioritise by exposure: take internet-reachable units offline within 24 hours, patch internal units in the next change window, and move unpatchable models into the hardware replacement backlog.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory all Dahua devices (IPC-HX3XXX, IPC-HX5XXX, IPC-HUM7XXX, VTO75X95X, VTO65XXX, VTH542XH, SD1A1, SD22, SD49, SD50) via DHCP leases, ARP tables and an Nmap sweep on TCP/37777 (Dahua DVRIP), TCP/80, TCP/443, TCP/554 (RTSP).
      • Deploy the vendor-fixed firmware: IPC-HUM7XXX from 2.820.0000000.5.r.210705, IPC-HX3XXX from 2.800.0000000.29.r.210630, IPC-HX5XXX from 2.820.0000000.18.r.210705, SD1A1/SD22/SD49/SD50 from 2.812.0000007.0.r.210706. For video intercom models, consult the vendor advisory for the exact fixed build.
      • Remove all Dahua devices from the public internet until patched: disable perimeter port-forwards on 37777/80/443/554 immediately and check Shodan/Censys exposure for your own ASN.
      • Rotate admin credentials after patching — the bypass sidesteps authentication entirely, so existing passwords must be treated as compromised. Enumerate all local and ONVIF accounts on each device and delete any unknown ones.
      • Export each device configuration and inspect for unauthorised RTSP pull targets, SMTP snapshot recipients, FTP upload servers and extra NTP/DNS entries — classic persistence vectors on hijacked cameras.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: dedicated CCTV/physical-access VLAN with no L3 routing except to the NVR/VMS. Egress on the camera VLAN restricted to NTP, DNS and the VMS — no internet.
      • Perimeter: for remote access, go through VPN/ZTNA into the VMS only, never directly to the camera. If direct web UI access is unavoidable, front it with a reverse proxy enforcing mTLS.
      • IPS rule: Suricata/Snort signature on DVRIP login packets containing a NetKeyboard type argument on TCP/37777; drop the matching variants. Check ET Open and vendor communities for existing "Dahua NetKeyboard" or CVE-2021-33044 rules.
      • Device hardening: disable UPnP, multicast, the P2P cloud feature (easy4ip), change default SNMP communities, require authentication on ONVIF.
      • Backend monitoring: only the VMS should initiate TCP/37777. Firewall-deny plus alert on any other source talking to camera IPs on that port.
      • End-of-life review: devices without an available patch (older firmware branches) go into the replacement plan; interim measure is physical disconnection or an isolated non-routed VLAN.

    3. Runbook step 3

      Detection rules

      • Zeek/Suricata: TCP sessions to port 37777 whose login request carries a "NetKeyboard" field or type values outside the expected client set — Sigma-style shape: network.dest_port:37777 AND payload contains "NetKeyboard".
      • Firewall/flow logs: traffic to TCP/37777 or TCP/80 toward camera IPs from any non-VMS source. KQL example: CommonSecurityLog | where DestinationPort in (37777,80,554) and DeviceVendor != "VMS-Host" and DestinationIP in (CameraSubnet).
      • Camera audit log (shipped via syslog to the SIEM): successful login without a prior failed attempt from an unknown source IP; newly created user accounts; modifications of RTSP or snapshot destinations.
      • NetFlow anomaly: outbound traffic from camera IPs to anything other than NTP/DNS/VMS — in particular IRC ports, Tor nodes, mining pools or HTTP beacons with atypical user agents (Mirai/Hajime variants frequently use Dahua footholds as botnet loaders).
      • EDR on the VMS host: unexpected outbound sessions from the VMS process to camera IPs that are not in inventory — a sign of lateral abuse from another foothold.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    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.

    Source: pwn.watch, CSA/SingCERT, NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    —Some Dahua IP Camera, Video Intercom, PTZ Dome Camera, Thermal Camera devices
    • Dahua IP Camera devices IPC-HX3XXX, IPC-HX5XXX, and IPC-HUM7XXX, Video Intercom devices VTO75X95X, VTO65XXX, and VTH542XH, PTZ D
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Otherdahuasecurityipc-hum7xxx_firmware—
    Otherdahuasecurityipc-hx3xxx_firmware—
    Otherdahuasecurityipc-hx5xxx_firmware—
    Otherdahuasecuritysd1a1_firmware—
    Otherdahuasecuritysd22_firmware—
    Otherdahuasecuritysd49_firmware—
    Otherdahuasecuritysd50_firmware—
    Otherdahuasecuritysd52c_firmware—
    Otherdahuasecuritysd6al_firmware—
    Otherdahuasecuritytpc-bf1241_firmware—
    Otherdahuasecuritytpc-bf2221_firmware—
    Otherdahuasecuritytpc-bf5x01_firmware—
    Otherdahuasecuritytpc-bf5x21_firmware—
    Otherdahuasecuritytpc-pt8x21b_firmware—
    Otherdahuasecuritytpc-sd2221_firmware—
    Otherdahuasecuritytpc-sd8x21_firmware—
    Otherdahuasecurityvth-542xh_firmware—
    Otherdahuasecurityvto-65xxx_firmware—
    Otherdahuasecurityvto-75x95x_firmware—

    Weakness classes (CWE)

    • CWE-287Improper Authentication

      Class

      When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

      Entry at MITRE CWE-287

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    Reference tagged as exploitseclists.org (opens in a new tab)PoC (publicly reported)reported, not verified—
    Packet StormDahua Authentication Bypass (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)Camera-Dahua-Research-l-h-ng-CVE-2021-33044 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • dahuasecurity.comsupport/cybersecurity/details/957x_refsource_MISC, Vendor advisory
    • seclists.org20211005 [Update]: Dahua Authentication bypass (CVE-2021-33044, CVE-2021-33045)Mailing list, x_refsource_FULLDISC, Exploit, Mailing list, Third-party advisory
    • packetstormsecurity.comfiles/164423/Dahua-Authentication-Bypass.htmlx_refsource_MISC, Exploit, Third-party advisory, Vulnerability database
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33044government-resource, US government resource
    • pwn.watchpwn.watch: Dahua IP Camera Firmware: 2 actively exploited vulnerabilitiespwn-watch
    • dahuasecurity.comDahua advisory: CVE-2021-33044pwn-watch
    • NVD (NIST)NVD: CVE-2021-33044pwn-watch
    • NVD (NIST)NVD: CVE-2021-33045pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
    • pwn.watchpwn.watch: Dahua cameras and recorders hijacked through Easy4IP P2P cloud access, CERT-UA warnspwn-watch
    • itweek.com.uaЗловмисники можуть отримати контроль над камерами та відеореєстраторами Dahua через хмарний доступ (CERT-UA warning)pwn-watch
    • hunt.ioOperation CameraSwarm: Over 14,000 Dahua cameras compromised across Ukraine and Russiapwn-watch
    • therecord.mediaUkraine warns hackers are exploiting Chinese-made Dahua surveillance cameraspwn-watch
    • thehackernews.comAttackers Hijack Dahua IP Cameras in Ukraine Using P2P Access and Auth Weaknessespwn-watch
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