CVE-2018-9995 in DVR4104
Summary
by MITRE
TBK DVR4104 and DVR4216 devices allow remote attackers to bypass authentication via a "Cookie: uid=admin" header, as demonstrated by a device.rsp?opt=user&cmd=list request that provides credentials within JSON data in a response.
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Analysis
by VulDB Data Team • 08/13/2024
The TBK DVR4104 and DVR4216 digital video recorder devices present a critical authentication bypass vulnerability that allows remote attackers to gain administrative access without proper credentials. This vulnerability stems from improper session management and authentication validation mechanisms within the device's web interface. The flaw specifically manifests when an attacker crafts a malicious HTTP request that includes a specially formatted cookie header containing uid=admin, which the device accepts as valid authentication. This type of vulnerability falls under CWE-287 which addresses improper authentication issues in software systems.
The technical implementation of this vulnerability exploits the device's response handling mechanism in the device.rsp endpoint with parameters opt=user and cmd=list. When an attacker sends a request with the malicious cookie header, the system processes this request and returns JSON data containing administrative credentials within the response payload. This design flaw demonstrates a lack of proper input validation and session token verification, allowing attackers to manipulate the authentication flow through crafted HTTP headers. The vulnerability exists because the device does not properly validate the authenticity of the uid=admin cookie value, instead accepting it as legitimate without proper cryptographic verification or session state checking.
The operational impact of this vulnerability is severe as it provides full administrative access to the DVR devices, enabling attackers to view, modify, or delete video recordings, change system configurations, access user accounts, and potentially compromise the entire surveillance network. Remote attackers can exploit this vulnerability from outside the network perimeter without requiring any local access or prior authentication credentials, making it particularly dangerous for security-conscious organizations relying on these devices for physical security monitoring. The vulnerability essentially renders the device's built-in authentication mechanism ineffective, allowing unauthorized access to sensitive video surveillance data and system controls.
Organizations should immediately implement network segmentation to isolate these devices from critical network segments and apply firmware updates from the vendor if available. The recommended mitigations include implementing proper input validation for all HTTP headers, enforcing strong session management with cryptographically secure tokens, and disabling unnecessary web services or ports that expose the vulnerable endpoints. Security professionals should also consider deploying network monitoring solutions to detect suspicious cookie header patterns and implement web application firewalls to filter malicious requests. This vulnerability aligns with ATT&CK technique T1110 which covers credential access through exploitation of weak or default credentials, and T1071 which addresses application layer protocol usage for command and control communications. Organizations must conduct thorough vulnerability assessments of all networked security devices to identify similar authentication bypass flaws and ensure proper security configurations are in place to prevent unauthorized access to critical surveillance infrastructure.