CVE-2018-20499 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition before 11.x before 11.4.13, 11.5.x before 11.5.6, and 11.6.x before 11.6.1. It allows SSRF.
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Analysis
by VulDB Data Team • 03/18/2024
This vulnerability represents a server-side request forgery flaw that affected GitLab installations across multiple version streams including community and enterprise editions. The issue stems from inadequate input validation within the application's request handling mechanisms, specifically when processing external resource requests. Attackers could exploit this weakness to make unauthorized requests to internal systems that would otherwise be protected by network segmentation. The vulnerability impacts versions prior to 11.4.13 in the 11.x series, 11.5.6 in the 11.5.x series, and 11.6.1 in the 11.6.x series, indicating a widespread exposure period. This type of vulnerability falls under the CWE-918 category of Server-Side Request Forgery, which is classified as a critical security weakness in web applications. The flaw enables attackers to bypass normal access controls and potentially access internal network resources that are not directly exposed to the internet.
The operational impact of this vulnerability extends beyond simple data theft or unauthorized access. An attacker could leverage this SSRF vulnerability to perform reconnaissance activities against internal systems, potentially discovering additional vulnerable services or applications running on the same network infrastructure. The attack vector typically involves crafting malicious requests that cause the GitLab server to initiate connections to internal IP addresses or domains, effectively allowing the attacker to probe internal network topology and services. This capability significantly increases the attack surface for organizations using affected GitLab versions, as it provides a potential pathway for lateral movement within the network. The vulnerability is particularly concerning in enterprise environments where GitLab serves as a central collaboration platform and may have elevated privileges to access various internal systems.
Mitigation strategies for this vulnerability primarily focus on immediate version upgrades to the patched releases mentioned in the advisory. Organizations should prioritize updating their GitLab installations to versions 11.4.13, 11.5.6, or 11.6.1 respectively, depending on their current version stream. Network-level mitigations can include implementing strict firewall rules that restrict outbound connections from the GitLab server to internal networks, particularly blocking connections to common internal services such as internal dns servers, databases, or management interfaces. Additionally, organizations should consider implementing web application firewalls or proxy configurations that can detect and block suspicious request patterns that may indicate SSRF attempts. The ATT&CK framework categorizes this vulnerability under the T1071.004 technique for Application Layer Protocol: DNS, which is often used in conjunction with SSRF attacks to gather information about internal network resources. Security teams should also implement monitoring and logging controls to detect unusual outbound network requests that could indicate exploitation attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications and services within the organization's infrastructure.