CVE-2018-8801 in Community Edition
Summary
by MITRE
GitLab Community and Enterprise Editions version 8.3 up to 10.x before 10.3 are vulnerable to SSRF in the Services and webhooks component.
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Analysis
by VulDB Data Team • 03/07/2023
The vulnerability identified as CVE-2018-8801 affects GitLab Community and Enterprise Edition installations running versions 8.3 through 10.x prior to 10.3, specifically targeting the Services and webhooks functionality. This represents a significant security weakness that allows attackers to perform server-side request forgery attacks against the GitLab instance and its underlying infrastructure. The flaw exists within the webhook configuration handling mechanism where user-provided URLs are not properly validated or sanitized before being used to make HTTP requests to external systems.
The technical implementation of this vulnerability stems from insufficient input validation within GitLab's webhook service integration components. When administrators configure webhooks for project notifications or integration with external services, the system accepts user-supplied URLs without adequate sanitization checks. This creates an environment where malicious actors can craft specially crafted webhook URLs that, when processed by GitLab's internal services, can cause the system to make unauthorized HTTP requests to internal network resources or external malicious endpoints. The vulnerability is classified under CWE-918 as a Server-Side Request Forgery, which specifically addresses the issue of unvalidated requests being made from a server to arbitrary destinations.
The operational impact of this vulnerability is substantial as it enables attackers to potentially access internal network resources that would normally be protected by firewalls or network segmentation. An attacker could leverage this flaw to probe internal services, access sensitive data stored on internal servers, or even establish command and control channels through the webhook infrastructure. The attack surface expands significantly since GitLab installations often have access to various internal systems including databases, internal APIs, and other network services that are not directly exposed to the internet. This vulnerability can be exploited to bypass traditional network security controls and gain unauthorized access to resources that should remain isolated from external networks.
Security practitioners should immediately implement mitigations including updating to GitLab version 10.3 or later where the vulnerability has been patched. Organizations should also consider implementing network segmentation controls that restrict outbound connections from GitLab instances to prevent unauthorized access to internal systems. Additionally, administrators should review and validate all webhook configurations to ensure that only trusted endpoints are configured, and implement strict access controls around webhook management interfaces. The ATT&CK framework categorizes this vulnerability under T1071.004 for Application Layer Protocol: DNS and T1046 for Network Service Scanning, as attackers can use the SSRF capability to map internal network topology and identify vulnerable services. Regular monitoring of webhook activity logs and implementing network-based detection mechanisms can help identify potential exploitation attempts before they succeed in accessing internal resources.