CVE-2018-18646 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition before 11.2.7, 11.3.x before 11.3.8, and 11.4.x before 11.4.3. It allows SSRF.
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Analysis
by VulDB Data Team • 06/13/2023
This vulnerability represents a server-side request forgery flaw that affects GitLab installations across multiple version streams including community and enterprise editions. The issue exists in the handling of external requests within the application's processing pipeline, creating a potential attack vector where malicious actors could manipulate the system to make unauthorized requests to internal or external resources. The vulnerability impacts versions prior to 11.2.7, 11.3.8, and 11.4.3 respectively, indicating a widespread exposure across the GitLab product line during that time 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 where user input is improperly validated before being used to construct HTTP requests.
The technical exploitation of this SSRF vulnerability occurs when GitLab processes user-supplied data that is subsequently used to make HTTP requests to external systems. Attackers can craft malicious inputs that cause the application to connect to internal network services that should normally be inaccessible from the outside, or to external systems controlled by the attacker. This allows for reconnaissance of internal network structures, potential access to internal services, and in some cases, privilege escalation or data exfiltration. The vulnerability is particularly dangerous because it can be leveraged to bypass network segmentation controls and gain access to systems that are typically protected by firewalls or other network security measures. The flaw essentially allows attackers to use the GitLab application as a proxy to make requests that would otherwise be blocked by network security controls.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable full compromise of the GitLab installation and underlying infrastructure. An attacker who successfully exploits this vulnerability could gain access to internal services, databases, or other systems that are normally isolated from external access. This includes the potential to access sensitive configuration files, credentials stored within the application, or other internal resources that are typically protected by network security controls. The vulnerability could also be used to perform port scanning of internal networks, making it a valuable reconnaissance tool for attackers planning more extensive attacks. Organizations using affected GitLab versions face significant risk of unauthorized access and potential data breaches when this vulnerability is exploited, particularly in environments where GitLab is used for code repository management and CI/CD pipeline orchestration.
The recommended mitigation for this vulnerability involves immediate upgrading to patched versions of GitLab where the SSRF issue has been addressed through proper input validation and request handling mechanisms. Organizations should also implement network segmentation controls, firewall rules, and access controls to limit the potential impact of any successful exploitation attempts. Additionally, monitoring for unusual network traffic patterns and implementing web application firewalls can help detect and prevent exploitation attempts. The vulnerability demonstrates the critical importance of validating all user-supplied input and implementing proper access controls when making external requests from web applications. This aligns with ATT&CK technique T1071.004 for application layer protocol and T1046 for network service scanning, both of which are commonly associated with SSRF exploitation patterns. Organizations should also conduct regular security assessments and vulnerability scanning to identify similar issues in other applications and systems within their environment.