CVE-2021-44413 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. AddUser 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-2021-44413 represents a critical denial of service weakness within the reolink RLC-410W security camera firmware version 3.0.0.136_20121102. This issue specifically affects the cgiserver.cgi component responsible for parsing JSON commands, creating a pathway for malicious actors to disrupt the device's normal operational state. The vulnerability stems from inadequate input validation mechanisms within the JSON command parser, which fails to properly handle malformed or unexpected parameter structures. The affected device operates as a network-connected surveillance system, making it a potential target for attackers seeking to compromise security infrastructure. This particular flaw manifests when an attacker crafts a specific HTTP request containing an improperly formatted AddUser parameter that is not recognized as a valid JSON object structure. The technical implementation of this vulnerability aligns with CWE-20, which addresses improper input validation, and demonstrates how insufficient sanitization of user-supplied data can lead to system instability. The attack vector requires minimal complexity as it only necessitates sending a specially crafted HTTP request to the device's web interface, making it particularly dangerous for unpatched deployments.
The operational impact of this vulnerability extends beyond simple service disruption, as the device reboot process effectively renders the surveillance camera temporarily non-functional during the restart cycle. This creates a window of security exposure where the device cannot perform its primary function of monitoring and recording security events, potentially leaving facilities vulnerable to unauthorized access or criminal activity. The denial of service condition occurs because the JSON parser encounters an unexpected parameter structure and triggers an unhandled exception that results in system restart rather than graceful error handling. Network administrators and security personnel must recognize that this vulnerability can be exploited remotely without authentication requirements, making it particularly concerning for devices deployed in sensitive environments. The behavior of the device during exploitation demonstrates a lack of robust error recovery mechanisms, which is a fundamental security weakness in embedded systems. According to ATT&CK framework technique T1499.004, this vulnerability enables an attacker to perform application or system recovery interference, effectively compromising the availability of the security infrastructure.
Mitigation strategies for CVE-2021-44413 should prioritize immediate firmware updates from reolink to address the underlying JSON parsing implementation. Network segmentation and access control measures can help limit exposure by restricting direct internet access to the device and implementing firewall rules that filter suspicious HTTP requests. Security monitoring should include detection of unusual HTTP traffic patterns targeting the cgiserver.cgi endpoint, particularly requests containing malformed JSON structures. Organizations should implement network intrusion detection systems capable of identifying and blocking malicious HTTP requests that match the vulnerability signature. Physical security measures remain important as attackers may attempt to access the device through local network connections to exploit the vulnerability. Regular vulnerability assessments should include testing for similar input validation weaknesses in other network-connected devices within the security infrastructure. The remediation process must also consider the device's operational impact, as the firmware update process may require scheduled downtime for surveillance coverage. Organizations should maintain detailed inventory records of all network-connected security devices to ensure comprehensive vulnerability management coverage. Additionally, implementing network-based authentication and authorization controls can provide an additional layer of protection against unauthorized access attempts that could exploit this vulnerability.