CVE-2020-15819 in YouTrack
Summary
by MITRE
JetBrains YouTrack before 2020.2.10643 was vulnerable to SSRF that allowed scanning internal ports.
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Analysis
by VulDB Data Team • 08/09/2020
The vulnerability identified as CVE-2020-15819 affects JetBrains YouTrack versions prior to 2020.2.10643 and represents a server-side request forgery flaw that enables unauthorized internal port scanning. This vulnerability resides within the web application's handling of external resource requests, where insufficient input validation allows attackers to manipulate the application into making unintended requests to internal network resources. The flaw specifically impacts the application's ability to properly validate and restrict outbound connections, creating a pathway for malicious actors to probe internal systems and potentially discover sensitive services running on internal ports.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input parameters that are used to construct outbound HTTP requests. When a user submits a request to YouTrack that includes a URL parameter, the application fails to properly validate that the destination URL remains within acceptable boundaries. This validation gap allows attackers to craft requests that target internal IP addresses or hostnames, effectively bypassing normal network segmentation controls. The vulnerability operates at the application layer and can be exploited through various attack vectors including API calls, web forms, or direct HTTP requests that pass through the vulnerable YouTrack instance.
The operational impact of this vulnerability extends beyond simple port scanning capabilities to potentially expose critical internal infrastructure to reconnaissance attacks. An attacker could leverage this flaw to map internal network topology, identify running services, and potentially discover systems that are not properly secured or isolated from external access. This reconnaissance capability significantly increases the attack surface for organizations using vulnerable YouTrack instances, as it provides attackers with valuable information about internal systems that may have additional vulnerabilities. The vulnerability particularly affects development and project management environments where YouTrack instances often serve as central hubs for internal collaboration and may have access to sensitive development resources.
Organizations should immediately apply the available patches or updates to JetBrains YouTrack to address this vulnerability, as the risk of exploitation increases with the exposure time. The recommended mitigation strategy includes implementing network segmentation controls, deploying web application firewalls to monitor and filter outbound requests, and conducting thorough network audits to identify any potential unauthorized access that may have occurred. Additionally, organizations should consider implementing monitoring solutions that can detect unusual outbound traffic patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-918, which addresses server-side request forgery, and represents a significant concern within the ATT&CK framework under the reconnaissance and initial access phases, particularly the technique of port scanning and network discovery. The vulnerability demonstrates the critical importance of proper input validation and the potential consequences of inadequate security controls in web applications that interact with external resources.