CVE-2021-44371 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. SetEmail param is not object. An attacker can send an HTTP request to trigger this vulnerability.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/02/2022
The vulnerability identified as CVE-2021-44371 represents a critical denial of service condition within the cgiserver.cgi component of reolink RLC-410W firmware version 3.0.0.136_20121102. This issue specifically targets the JSON command parser functionality that processes incoming HTTP requests to the device's web interface. The flaw manifests when the system receives a malformed HTTP request containing a SetEmail parameter that does not conform to the expected object structure, creating a parsing inconsistency that ultimately results in system reboot. The vulnerability resides in the device's web server implementation and demonstrates poor input validation practices that fail to properly sanitize or validate JSON payload structures before processing.
The technical exploitation of this vulnerability occurs through a carefully crafted HTTP request that manipulates the SetEmail parameter within the JSON command parser. When the cgiserver.cgi component attempts to process this malformed parameter, it encounters an unexpected data structure that causes the system to crash and subsequently reboot. This behavior aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios, though the specific manifestation here involves improper handling of JSON object structures rather than traditional buffer overflows. The vulnerability operates at the application layer and requires no authentication or specialized privileges to exploit, making it particularly concerning for network-connected devices.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise device availability and integrity within security ecosystems. Repeated exploitation can lead to persistent service degradation, creating a denial of service condition that affects legitimate users and potentially providing attackers with opportunities to disrupt surveillance operations. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and represents a weak point in the device's defensive posture that could enable further exploitation attempts. The device's inability to properly handle malformed JSON input creates a persistent entry point that attackers can leverage to maintain control over device availability, particularly in environments where continuous surveillance is critical.
Mitigation strategies for CVE-2021-44371 should prioritize firmware updates from reolink to address the root cause of the JSON parsing vulnerability. Network administrators should implement firewall rules to restrict access to the device's web interface and HTTP ports, particularly in environments where the device is exposed to untrusted networks. Additional protective measures include deploying intrusion detection systems that can identify malformed HTTP requests targeting the affected parameter structure and implementing network segmentation to limit the potential impact of successful exploitation attempts. Organizations should also consider disabling unnecessary web services and implementing strict input validation at network boundaries to prevent malformed requests from reaching the vulnerable device components. Regular vulnerability assessments and security audits of networked devices are essential to identify similar parsing vulnerabilities that may exist in other components of the device's software stack.