CVE-2021-44408 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. TestFtp param is not object. An attacker can send an HTTP request to trigger this vulnerability.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 02/02/2022
The CVE-2021-44408 vulnerability represents a critical denial of service flaw within the reolink RLC-410W security camera firmware version 3.0.0.136_20121102. This vulnerability specifically targets the cgiserver.cgi JSON command parser functionality, which serves as the primary interface for remote management and configuration of the device. The flaw manifests when the system processes HTTP requests containing malformed JSON data, particularly in the TestFtp parameter field. This vulnerability falls under the CWE-121 heap-based buffer overflow category, where improper input validation leads to system instability. The device's JSON parser fails to properly validate the data type of the TestFtp parameter, expecting an object structure but receiving malformed input that triggers unexpected behavior.
The technical exploitation of this vulnerability occurs through a carefully crafted HTTP request that specifically targets the cgiserver.cgi component. When the system encounters an HTTP request with an improperly formatted TestFtp parameter that is not an object as expected, the JSON parser fails to handle the malformed input gracefully. Instead of rejecting the malformed request or properly processing the input, the parser executes code that results in an immediate system reboot. This behavior constitutes a classic denial of service attack vector that can be exploited remotely without requiring authentication or specialized privileges. The vulnerability demonstrates poor input validation practices and inadequate error handling within the device's web server implementation, making it susceptible to arbitrary code execution that ultimately manifests as a system restart.
The operational impact of CVE-2021-44408 extends beyond simple service disruption, as it can effectively render the security camera completely inoperable for extended periods. Network administrators responsible for surveillance systems relying on affected reolink devices face significant operational challenges when this vulnerability is exploited, as the cameras become unavailable for monitoring purposes until manual intervention occurs. The reboot effect creates a window of vulnerability where security monitoring is completely absent, potentially allowing unauthorized access to the protected environment. This type of attack aligns with the ATT&CK technique T1499.004 for network denial of service, where adversaries target network infrastructure to disrupt operations. The vulnerability affects both the availability and reliability of security monitoring systems, particularly in environments where continuous surveillance is critical.
Mitigation strategies for this vulnerability should include immediate firmware updates from reolink to address the specific JSON parsing flaw. Network administrators should implement network segmentation to limit access to affected devices, particularly restricting HTTP access to trusted networks only. The implementation of web application firewalls can help detect and block malformed HTTP requests targeting the cgiserver.cgi endpoint. Additionally, monitoring for unusual reboot patterns or HTTP request patterns can serve as early warning indicators of potential exploitation attempts. Organizations should also consider disabling unnecessary HTTP services or implementing access controls that restrict which IP addresses can communicate with the device's web interface. The vulnerability highlights the importance of input validation and proper error handling in embedded systems, particularly those used for security-critical applications where availability is paramount. This issue demonstrates why adherence to secure coding practices and regular security assessments are essential for maintaining the integrity of networked security devices.