CVE-2021-44376 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. SetIsp param is not object. An attacker can send an HTTP request to trigger this vulnerability.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 02/02/2022
The vulnerability identified as CVE-2021-44376 represents a critical denial of service flaw within the reolink RLC-410W security camera firmware version 3.0.0.136_20121102. This issue resides in the cgiserver.cgi component which handles JSON command parsing for the device's web interface. The vulnerability specifically affects the SetIsp parameter processing functionality where the system fails to properly validate input data types. The flaw manifests when an attacker crafts a malicious HTTP request that targets the JSON parser with malformed data containing the SetIsp parameter. According to CWE-20, this vulnerability stems from improper input validation where the system expects an object type but receives an unexpected data structure. The attack vector exploits the lack of proper type checking in the JSON command parser, allowing an unauthenticated remote attacker to send a specially crafted HTTP request that triggers a system reboot.
The technical execution of this vulnerability involves sending an HTTP request with a malformed SetIsp parameter that does not conform to the expected JSON object structure. When the cgiserver.cgi component processes this request, it attempts to parse the parameter without proper validation, leading to a critical system error that results in an automatic device reboot. This behavior constitutes a classic denial of service attack pattern where legitimate service availability is compromised. The vulnerability operates at the application layer and requires no authentication credentials to exploit, making it particularly dangerous for networked security devices. The root cause aligns with ATT&CK technique T1499.004 which describes network denial of service attacks targeting network infrastructure devices. The system's failure to implement proper input sanitization and type validation creates a condition where malformed JSON data can cause unexpected behavior in the application's control flow.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the availability of security monitoring capabilities. When the reolink RLC-410W device reboots repeatedly, it creates gaps in surveillance coverage that adversaries can exploit. The device becomes temporarily inaccessible to authorized users while it restarts, potentially leaving monitored areas unprotected during the reboot cycle. This vulnerability particularly affects organizations relying on continuous surveillance where even brief service interruptions can have significant security implications. The ease of exploitation means that any attacker with network access to the device can trigger the denial of service condition, making it a high-risk vulnerability for both enterprise and home security deployments. Organizations using this specific camera model should consider the potential for coordinated attacks that could cause multiple devices to reboot simultaneously, creating widespread service disruption across monitored environments.
Mitigation strategies for CVE-2021-44376 should focus on immediate firmware updates from reolink to address the underlying parsing logic flaw. Network segmentation and access controls should be implemented to limit exposure of the affected device to untrusted networks. The implementation of web application firewalls can help filter malicious HTTP requests before they reach the vulnerable cgiserver.cgi component. Additionally, monitoring network traffic for suspicious patterns related to the SetIsp parameter can help detect exploitation attempts. Organizations should also consider disabling unnecessary web interface access and implementing strict authentication controls. The vulnerability highlights the importance of proper input validation and type checking in embedded systems, particularly those handling JSON data in security-critical applications. Regular security assessments of networked devices should include verification of firmware versions and patch status to prevent exploitation of known vulnerabilities. The incident underscores the necessity of secure coding practices and proper validation of all external input data within networked security appliances.