CVE-2020-19003 in Gate One
Summary
by MITRE • 10/06/2021
An issue in Gate One 1.2.0 allows attackers to bypass to the verification check done by the origins list and connect to Gate One instances used by hosts not on the origins list.
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Analysis
by VulDB Data Team • 10/09/2021
The vulnerability identified as CVE-2020-19003 affects Gate One version 1.2.0, a web-based terminal emulator and SSH client that provides secure access to remote systems. This security flaw represents a critical authorization bypass that undermines the intended access controls of the application. The vulnerability specifically targets the origins list validation mechanism, which is designed to restrict connections to only those hosts explicitly authorized by the system administrator. The origins list serves as a fundamental security control that prevents unauthorized access to Gate One instances by verifying the source of incoming connection requests against a predetermined whitelist of approved hosts.
The technical implementation of this vulnerability stems from a flaw in the verification logic that processes incoming connection requests. Attackers can exploit this weakness to circumvent the origins list validation checks that should prevent connections from unauthorized hosts. This bypass allows malicious actors to establish connections to Gate One instances that are configured to only accept connections from specific hosts, effectively neutralizing the network-level access controls that are meant to protect the system. The flaw likely resides in how the application processes or validates the origin headers or connection parameters that should be checked against the configured origins list before establishing a session.
The operational impact of this vulnerability is significant as it enables unauthorized remote access to systems protected by Gate One. An attacker who successfully exploits this vulnerability can gain access to the Gate One instance and subsequently access all systems and resources that are accessible through that instance. This creates a potential attack vector that could lead to full system compromise, especially if the Gate One instance provides access to critical infrastructure components or sensitive data systems. The vulnerability essentially transforms a controlled access environment into an open one, removing the network-level security boundaries that were intended to protect the system.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a classic case of authorization bypass where the system fails to properly validate user or host credentials before granting access. From an ATT&CK framework perspective, this vulnerability maps to T1078 which covers valid accounts and T1190 which involves exploitation of remote services, as it allows attackers to establish unauthorized connections to remote systems through the compromised Gate One instance. Organizations should prioritize immediate remediation by updating to a patched version of Gate One that properly validates the origins list, implementing additional network-level controls such as firewall rules that restrict access to the Gate One instance, and conducting thorough security assessments to identify any potential compromise that may have occurred through this vulnerability.