CVE-2021-44414 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. DelUser 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
This vulnerability resides in the cgiserver.cgi component of reolink RLC-410W firmware version 3.0.0.136_20121102, representing a critical denial of service flaw that can be exploited to remotely reboot the affected device. The vulnerability manifests within the JSON command parser functionality where the system fails to properly validate input parameters, specifically the DelUser parameter which is expected to be an object but is instead being treated as a scalar value. This improper handling creates a condition where malformed HTTP requests can cause the device to crash and subsequently reboot, effectively denying legitimate users access to the surveillance system. The vulnerability is particularly concerning as it requires no authentication to exploit, making it accessible to any remote attacker who can reach the device over the network.
The technical flaw stems from inadequate input validation and parameter parsing within the web server component of the firmware. When the system processes an HTTP request containing a malformed DelUser parameter, it attempts to parse the parameter without proper type checking, leading to a memory access violation or stack corruption that results in system instability. This behavior aligns with CWE-20: Improper Input Validation, where insufficient validation of input parameters leads to unexpected system behavior. The vulnerability demonstrates poor defensive programming practices where the system does not properly handle unexpected data types or malformed JSON structures, creating a path for arbitrary code execution or system termination through controlled input manipulation.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the integrity of the surveillance infrastructure. In a security context, this denial of service condition can be leveraged as part of a broader attack strategy to disable security monitoring capabilities, potentially enabling other attacks to go undetected. The ability to remotely trigger a reboot without authentication creates a persistent threat vector that can be exploited repeatedly, making it particularly dangerous for security-critical deployments. Organizations relying on these devices for perimeter security or surveillance may experience complete system outages during critical periods, potentially leaving facilities vulnerable to physical security breaches. This vulnerability directly impacts the availability aspect of the CIA triad, as it can be used to deny legitimate users access to their security systems.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from reolink, as the manufacturer would have likely released a patch addressing the input validation issue. Network segmentation and access controls should be implemented to limit exposure of these devices to untrusted networks, while monitoring for unusual reboot patterns or HTTP request patterns can help detect exploitation attempts. Organizations should also consider implementing intrusion detection systems that can identify malformed JSON requests or unusual HTTP traffic patterns targeting the cgiserver component. From an ATT&CK framework perspective, this vulnerability maps to T1499.004: Endpoint Denial of Service, where adversaries can disrupt services through system resource exhaustion or process termination. Additionally, the vulnerability could be leveraged as part of a reconnaissance phase to identify other potential entry points within the network, making early remediation crucial for maintaining overall network security posture.