CVE-2021-40416 in RLC-410W
Summary
by MITRE • 01/28/2022
An incorrect default permission vulnerability exists in the cgiserver.cgi cgi_check_ability functionality of reolink RLC-410W v3.0.0.136_20121102. All the Get APIs that are not included in cgi_check_ability are already executable by any logged-in users. 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-2021-40416 represents a critical access control flaw within the Reolink RLC-410W security camera firmware version 3.0.0.136_20121102. This issue stems from improper default permission configuration in the cgiserver.cgi component, specifically within the cgi_check_ability functionality that governs API access controls. The flaw creates a dangerous privilege escalation vector where authenticated users can execute unauthorized API calls that should be restricted to administrative or privileged accounts only. The vulnerability manifests when the system fails to properly validate user permissions for certain GET API endpoints, allowing any authenticated user to access functionality that should remain protected.
This technical flaw operates at the application layer of the network stack and constitutes a direct violation of the principle of least privilege as defined in cybersecurity best practices. The improper implementation of access control checks in the cgi_check_ability function creates a pathway where user sessions can be leveraged to perform administrative actions without proper authorization. The vulnerability is particularly concerning because it affects the core authentication and authorization mechanisms of the device, potentially allowing attackers to escalate privileges from standard user accounts to full administrative control. The issue aligns with CWE-284 which addresses improper access control and specifically relates to inadequate permissions for critical system functions.
The operational impact of this vulnerability extends beyond simple unauthorized access, creating potential for complete device compromise and network infiltration. An attacker who gains access to any logged-in user session can leverage this flaw to execute arbitrary API calls that may include system configuration changes, firmware updates, user management functions, or data exfiltration capabilities. The attack vector is straightforward requiring only HTTP request manipulation, making it accessible to adversaries with basic web application exploitation knowledge. This vulnerability significantly weakens the security posture of the device and can be exploited to establish persistent access or cause denial of service conditions. The risk is amplified by the fact that the default configuration leaves critical administrative functions accessible to all authenticated users, essentially creating a backdoor for any user who can establish a valid session.
Mitigation strategies should focus on immediate firmware updates from Reolink to address the permission validation flaw, combined with network segmentation to limit access to these devices to trusted networks only. Network administrators should implement strict firewall rules that restrict access to the camera's management interfaces and consider disabling unnecessary API endpoints. The implementation of multi-factor authentication and regular access control audits can help reduce the impact of such vulnerabilities. Additionally, organizations should conduct comprehensive security assessments of their IoT device inventory to identify similar permission flaws in other networked equipment. This vulnerability demonstrates the critical importance of proper access control implementation in embedded systems and aligns with ATT&CK technique T1078 which covers legitimate credentials and valid accounts as a means of persistence and privilege escalation in compromised environments.