CVE-2021-44387 in RLC-410W
Summary
by MITRE • 01/29/2022
A denial of service vulnerability exists in the cgiserver.cgi JSON command parser functionality of reolink RLC-410W v3.0.0.136_20121102. A specially-crafted HTTP request can lead to a reboot. SetPtzPreset param is not object. An attacker can send an HTTP request to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/02/2022
The vulnerability CVE-2021-44387 represents a critical denial of service condition affecting the reolink RLC-410W security camera device running firmware version v3.0.0.136_20121102. This issue resides within the cgiserver.cgi component's JSON command parser functionality, which processes incoming HTTP requests containing camera control commands. The device's web interface utilizes this CGI script to handle various camera operations including PTZ (pan-tilt-zoom) control functions, making it a prime target for exploitation. The vulnerability specifically manifests when the SetPtzPreset parameter is improperly formatted within JSON requests, creating a parsing error that ultimately results in device reboot. This type of vulnerability falls under CWE-129 Input Validation, as the system fails to properly validate and sanitize incoming JSON parameters before processing them. The attack vector requires only a simple HTTP request to be sent to the device's web server, making it particularly dangerous as it can be exploited remotely without requiring authentication or physical access.
The technical exploitation of this vulnerability occurs through malformed HTTP requests that target the JSON parser within the cgiserver.cgi script. When an attacker crafts a request containing a SetPtzPreset parameter that does not conform to the expected object structure, the parser fails to handle this invalid input gracefully. Instead of returning an appropriate error message or rejecting the malformed request, the system enters a state where it reboots itself as a response to the parsing failure. This behavior demonstrates a lack of proper exception handling and input validation within the device's firmware implementation. The vulnerability is particularly concerning because it operates at the application layer, targeting the web server component that manages user interactions with the camera's features. The reboot effect essentially creates a persistent denial of service condition that can be repeatedly triggered by an attacker, rendering the security camera inoperative until manual intervention or automatic reboot occurs. This aligns with ATT&CK technique T1499.004 for Network Denial of Service attacks, where adversaries exploit weaknesses in network services to disrupt availability.
The operational impact of CVE-2021-44387 extends beyond simple service disruption to potentially compromise security monitoring capabilities. Security cameras serve as critical components of surveillance systems, and their unavailability can leave protected areas vulnerable to unauthorized access or criminal activity. The automatic reboot mechanism means that any attempt to exploit this vulnerability will result in immediate service interruption, potentially during critical security events or peak monitoring periods. Organizations relying on these devices for perimeter security, inventory monitoring, or access control may experience significant operational disruptions when this vulnerability is exploited. The remote nature of the attack means that threat actors can target multiple devices simultaneously without requiring physical presence, making this vulnerability particularly dangerous in environments with numerous connected cameras. The vulnerability affects not only individual devices but also the broader network infrastructure, as the repeated reboots can overwhelm network management systems and generate excessive alert traffic. Network administrators may find themselves dealing with cascading failures as multiple cameras in a networked system repeatedly reboot, creating a significant burden on system maintenance and monitoring efforts.
Mitigation strategies for CVE-2021-44387 should focus on both immediate protective measures and long-term firmware updates. The most effective immediate solution involves updating the device firmware to a version that addresses the JSON parsing vulnerability, which would typically include proper input validation and exception handling for malformed parameters. Network segmentation should be implemented to isolate security camera systems from critical business networks, reducing the potential impact of exploitation. Access control measures such as restricting HTTP access to trusted IP addresses and implementing firewall rules to monitor and filter incoming requests can help prevent exploitation attempts. Additionally, organizations should consider implementing network monitoring solutions that can detect unusual reboot patterns or repeated connection attempts to camera devices. The vulnerability demonstrates the importance of proper input validation and error handling in embedded systems, as highlighted by CWE-20 Improper Input Validation and CWE-707 Improper Neutralization of Input During Web Page Generation. Security teams should also implement regular vulnerability scanning of their networked devices to identify similar issues in other embedded systems, as this type of vulnerability is common in IoT and embedded security devices where resource constraints often lead to insufficient security controls.