CVE-2021-44397 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. rtmp=start 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-2021-44397 affects the reolink RLC-410W security camera device running firmware version v3.0.0.136_20121102. This issue resides within the cgiserver.cgi component which handles JSON command parsing functionality. The device operates as a network video recorder with web-based management capabilities, making it a critical component in surveillance infrastructure deployments. The vulnerability represents a significant security flaw that could be exploited to disrupt the availability of the device, potentially compromising security monitoring operations in both residential and commercial environments.
The technical flaw manifests in the JSON command parser implementation where the system fails to properly validate the structure of incoming HTTP requests. Specifically when processing the rtmp=start parameter, the device expects a properly formatted JSON object but does not adequately validate that the parameter actually constitutes a valid object structure. This parsing error occurs within the web server component that handles CGI requests, creating a condition where malformed input can cause the device to crash and subsequently reboot. The vulnerability stems from inadequate input sanitization and lack of proper error handling in the JSON parsing logic, which falls under CWE-20 Input Validation and CWE-707 Improper Neutralization of Input During Web Page Generation.
The operational impact of this vulnerability extends beyond simple denial of service as it creates a potential attack vector for persistent disruption of security monitoring systems. An attacker capable of sending HTTP requests to the device can trigger a reboot cycle that may occur repeatedly, effectively rendering the camera inoperative for security purposes. This disruption could occur during critical security events when the camera is needed most, potentially creating blind spots in surveillance coverage. The vulnerability is particularly concerning in environments where multiple devices are deployed, as a single compromised device could be used as a foothold for further attacks or to create a distributed denial of service scenario against the surveillance network.
Mitigation strategies should focus on immediate firmware updates from reolink to address the specific parsing vulnerability in the cgiserver.cgi component. Network segmentation and access controls should be implemented to limit direct internet exposure of the device, while monitoring should be established to detect unusual reboot patterns that may indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1499.004 Network Denial of Service which involves disrupting network services through various means including device reboots. Additionally, implementing web application firewalls and input validation controls at network boundaries can provide additional defense in depth. Organizations should also consider disabling unnecessary web management interfaces and using secure remote access methods to reduce the attack surface of these devices. Regular vulnerability assessments and firmware update schedules should be established to maintain protection against similar issues in the future, as this represents a classic example of how insufficient input validation can lead to critical system instability.