CVE-2021-44374 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. SetMask 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-2021-44374 represents a critical denial of service flaw within the reolink RLC-410W security camera firmware version 3.0.0.136_20121102. This issue specifically targets the cgiserver.cgi component which handles JSON command parsing for device configuration and management operations. The vulnerability stems from improper input validation and handling within the SetMask parameter processing functionality, creating a scenario where malformed HTTP requests can cause the device to unexpectedly reboot and become unavailable for legitimate use. The affected device operates as a network video recorder with web-based management capabilities, making it susceptible to remote exploitation through standard HTTP protocols.
The technical root cause of this vulnerability lies in the insufficient sanitization and validation of JSON payload parameters within the cgi server implementation. When the SetMask parameter is processed, the system fails to properly validate that the incoming data conforms to expected object structures before attempting to parse or execute operations. This parsing error creates a condition where malformed JSON input containing unexpected data types or structures causes the device's processing stack to crash, ultimately resulting in an automatic system reboot. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous in unsecured network environments. This flaw aligns with CWE-20, which addresses improper input validation, and represents a classic example of how inadequate parameter handling can lead to system instability and denial of service conditions.
The operational impact of this vulnerability extends beyond simple service disruption as it can be exploited by remote attackers to maintain persistent denial of service conditions against security camera infrastructure. The automatic reboot mechanism effectively neutralizes the device's ability to perform its core functions including video recording, motion detection, and network connectivity. In security-sensitive environments such as corporate facilities, retail locations, or residential properties, this vulnerability could result in complete loss of surveillance capabilities during critical time periods. The vulnerability's exploitation requires only basic HTTP request capabilities and can be automated through simple scripting tools, making it accessible to attackers with minimal technical expertise. This characteristic aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through exploitation of device vulnerabilities.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from reolink to address the specific parsing error in the cgiserver.cgi component. Network administrators should implement firewall rules to restrict access to the camera's web management interfaces and consider segmenting security camera networks from primary business networks. Additionally, monitoring for unusual reboot patterns or unauthorized HTTP requests to camera management ports should be implemented as part of security operations. The vulnerability demonstrates the importance of input validation in embedded systems and highlights the need for robust error handling mechanisms in network-facing applications. Organizations should also consider implementing device hardening measures including disabling unnecessary services, changing default credentials, and regularly auditing network-accessible devices for similar vulnerabilities. The remediation process should include verification that the updated firmware properly validates JSON parameter structures before processing, preventing the specific parsing error that leads to system instability.