CVE-2020-25239 in SINEMA Remote Connect Server
Summary
by MITRE • 03/16/2021
A vulnerability has been identified in SINEMA Remote Connect Server (All versions < V3.0). The webserver could allow unauthorized actions via special urls for unpriviledged users. The settings of the UMC authorization server could be changed to add a rogue server by an attacker authenticating with unprivilege user rights.
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Analysis
by VulDB Data Team • 04/01/2021
The vulnerability identified as CVE-2020-25239 affects SINEMA Remote Connect Server versions prior to V3.0, representing a critical authorization bypass flaw that undermines the security posture of industrial network infrastructure. This vulnerability resides within the webserver component of the SINEMA Remote Connect Server, which is designed to facilitate remote connectivity and management of industrial systems. The flaw allows unprivileged users to manipulate the UMC (Unified Management Console) authorization server settings through specially crafted URLs, effectively enabling unauthorized modification of the system's security configuration. This represents a significant weakness in the principle of least privilege, where users with minimal access rights can potentially escalate their privileges and compromise the entire remote connectivity infrastructure.
The technical nature of this vulnerability stems from improper input validation and access control mechanisms within the webserver's URL handling functionality. Attackers can exploit this weakness by constructing specific URL parameters that bypass normal authorization checks, allowing them to modify critical server configuration settings. The vulnerability specifically targets the UMC authorization server configuration, where an attacker with only basic user credentials can add rogue servers to the trusted configuration, essentially creating a backdoor within the legitimate system. This type of flaw falls under CWE-285, which addresses improper authorization issues, and represents a classic case of insufficient access control validation. The attack vector is particularly concerning as it requires minimal privileges to execute, making it accessible to users who should not have administrative capabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the integrity of the industrial communication infrastructure. An attacker who successfully exploits this vulnerability can introduce malicious servers into the UMC authorization configuration, potentially enabling man-in-the-middle attacks, data interception, or complete system compromise. The implications are severe for industrial environments where SINEMA Remote Connect Server is deployed, as these systems typically manage critical infrastructure components such as power grids, water treatment facilities, or manufacturing processes. The ability to add rogue servers means that attackers can redirect legitimate traffic to malicious endpoints, potentially causing operational disruptions or security breaches that could affect entire industrial networks. This vulnerability aligns with ATT&CK technique T1078 which covers Valid Accounts and privilege escalation techniques, particularly when unauthorized access is gained through legitimate system interfaces.
Organizations utilizing SINEMA Remote Connect Server should implement immediate mitigations to address this vulnerability. The primary recommendation is to upgrade to version V3.0 or later, where the authorization bypass has been corrected. Additionally, network segmentation should be implemented to limit access to the webserver component, and access controls should be strictly enforced through proper user privilege management. Regular security audits should be conducted to identify any unauthorized modifications to the authorization server configuration, and monitoring should be implemented to detect suspicious URL access patterns. The vulnerability demonstrates the importance of maintaining up-to-date security patches in industrial environments, where legacy systems often remain operational for extended periods without proper security updates. Organizations should also consider implementing network access controls and firewall rules that restrict direct access to the webserver component from untrusted networks, as this reduces the attack surface and limits the potential impact of such vulnerabilities.