CVE-2021-44393 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. GetIsp 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 identified as CVE-2021-44393 represents a critical denial of service condition within the reolink RLC-410W security camera device firmware version v3.0.0.136_20121102. This issue resides in the cgiserver.cgi component which processes JSON command requests through the web interface. The flaw manifests when the system receives an HTTP request containing a malformed GetIsp parameter that fails to properly structure the expected JSON object format. This particular vulnerability falls under the CWE-471 category of "Incorrectly Handling of Structured Data" and specifically relates to improper handling of JSON parsing operations within network services.
The technical execution of this vulnerability occurs through a carefully crafted HTTP request that targets the JSON command parser functionality of the device's web server component. When the cgiserver.cgi module encounters a GetIsp parameter that does not conform to the expected object structure, the system fails to properly validate or sanitize the input before processing. This parsing error triggers an unhandled exception within the firmware's command processing pipeline, resulting in an immediate system reboot. The vulnerability demonstrates characteristics consistent with CWE-691, indicating insufficient input validation that allows malformed data to propagate through the system's processing logic without proper error handling mechanisms.
The operational impact of this vulnerability extends beyond simple service disruption as it provides attackers with a reliable method to remotely compromise the availability of security monitoring equipment. The RLC-410W camera serves as a critical component in many surveillance networks, and its unexpected reboot can create gaps in security coverage that adversaries might exploit. This vulnerability is particularly concerning in environments where continuous monitoring is essential for security operations, as the device could be repeatedly targeted to maintain persistent service disruption. The attack requires minimal sophistication and can be executed through standard HTTP request mechanisms, making it accessible to threat actors with basic network reconnaissance capabilities.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1499.004 which covers "Endpoint Denial of Service" and represents a specific implementation of service disruption through firmware-level command parsing failures. The device's lack of proper input validation creates an attack surface that could be leveraged in broader network compromise attempts where adversaries might use the camera as a foothold for further infiltration. Organizations should consider implementing network segmentation to isolate such devices from critical infrastructure and ensure that firmware updates are applied promptly when vendor patches become available. The vulnerability highlights the importance of robust input validation and proper error handling in embedded network devices, particularly those serving security-critical functions where availability is paramount to overall system integrity.