CVE-2021-44396 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. Preview 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-2021-44396 represents a critical denial of service flaw within the reolink RLC-410W security camera device firmware version 3.0.0.136_20121102. This issue specifically targets the cgiserver.cgi component responsible for processing JSON commands, creating a scenario where legitimate system operations can be disrupted through malicious input manipulation. The affected device operates within the consumer and small business surveillance market segment, where reliability and continuous operation are paramount for security monitoring purposes.
The technical implementation of this vulnerability stems from inadequate input validation within the JSON command parser functionality. When the cgiserver.cgi component receives an HTTP request containing a malformed preview parameter, the system fails to properly handle the unexpected data structure. Specifically, the parser expects an object structure for the preview parameter but encounters malformed input that causes the device to enter an unstable state. This parsing error ultimately results in an automatic device reboot, effectively denying service to legitimate users who require continuous monitoring capabilities. The vulnerability operates at the application layer and can be exploited through standard HTTP protocols without requiring authentication or specialized tools.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise security monitoring operations. When a security camera repeatedly reboots due to malicious requests, it creates gaps in surveillance coverage that attackers could exploit. Network administrators responsible for maintaining surveillance systems may experience significant operational challenges as the device becomes unreliable and requires manual intervention to restore functionality. The vulnerability's exploitation is straightforward, requiring only basic HTTP request crafting capabilities, making it accessible to attackers with minimal technical expertise. This characteristic significantly increases the risk profile as it can be leveraged by both amateur and sophisticated threat actors to disrupt security operations.
Mitigation strategies for CVE-2021-44396 should prioritize immediate firmware updates from reolink to address the parsing vulnerability within the cgiserver.cgi component. Network segmentation and access control measures can provide temporary protection by restricting direct internet access to the affected devices and implementing proper firewall rules to filter suspicious HTTP requests. The vulnerability aligns with CWE-20 Improper Input Validation, which emphasizes the importance of robust data validation mechanisms to prevent malformed inputs from causing system instability. From an attack framework perspective, this vulnerability could be categorized under the ATT&CK technique T1499.004 Unauthorized Access to Network Devices, as it enables attackers to disrupt network security infrastructure. Organizations should also implement network monitoring solutions to detect unusual reboot patterns and establish incident response procedures specifically addressing device denial of service attacks. The vulnerability demonstrates the critical need for proper input sanitization and error handling in embedded systems, particularly those serving security-critical functions in network infrastructure.