CVE-2017-0926 in Community Edition
Summary
by MITRE
Gitlab Community Edition version 10.3 is vulnerable to an improper authorization issue in the Oauth sign-in component resulting in unauthorized user login.
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Analysis
by VulDB Data Team • 02/22/2023
The vulnerability identified as CVE-2017-0926 affects Gitlab Community Edition version 10.3 and represents a critical authorization flaw within the OAuth sign-in component. This issue stems from inadequate validation of user permissions and authentication states during the OAuth authentication process, creating a pathway for malicious actors to bypass normal access controls. The flaw exists in the way Gitlab handles OAuth token validation and user session management, allowing unauthorized individuals to potentially gain access to systems or data that should be restricted to legitimate users. The vulnerability specifically impacts the OAuth integration functionality that enables third-party applications to authenticate users through Gitlab's platform.
The technical root cause of this authorization issue lies in the improper handling of OAuth state parameters and session validation checks within the authentication flow. When users attempt to sign in through OAuth providers, the system fails to properly verify that the authentication request originates from a legitimate source or that the user has appropriate authorization levels. This weakness creates a condition where an attacker could manipulate the OAuth flow to escalate privileges or impersonate other users within the Gitlab environment. The flaw operates at the application layer and can be exploited without requiring elevated privileges or specialized tools beyond standard web application attack methodologies. According to CWE classification, this vulnerability maps to CWE-285: Improper Authorization, which specifically addresses issues where systems fail to properly enforce access controls during authentication processes.
The operational impact of this vulnerability extends beyond simple unauthorized access, potentially enabling attackers to gain persistent access to Gitlab repositories, user data, and system configurations. An attacker exploiting this flaw could access sensitive code repositories, modify project settings, manipulate user permissions, or even escalate privileges to administrative levels depending on the system's configuration. The vulnerability affects all users who rely on OAuth authentication methods within the affected Gitlab version, making it particularly dangerous in environments where multiple third-party applications integrate with the platform. Organizations using Gitlab for source code management and collaboration could face significant data exposure risks, including potential intellectual property theft, code manipulation, and unauthorized system modifications. This type of authorization bypass vulnerability aligns with ATT&CK technique T1078.004: Valid Accounts, where adversaries leverage legitimate credentials to maintain access to systems.
Mitigation strategies for CVE-2017-0926 should prioritize immediate remediation through the official Gitlab security update addressing this specific authorization flaw. Organizations should implement comprehensive monitoring of authentication logs to detect unusual login patterns or unauthorized access attempts that might indicate exploitation of this vulnerability. Network segmentation and access controls should be reviewed to limit the blast radius if exploitation occurs, while multi-factor authentication should be enforced for all administrative accounts. Security teams should conduct thorough vulnerability assessments to identify any potential exploitation attempts and implement proper session management controls. Regular security audits of OAuth integrations and authentication flows should be performed to ensure that similar authorization flaws do not exist in other components of the Gitlab platform or integrated applications. Additionally, organizations should establish incident response procedures specifically tailored to address authentication bypass vulnerabilities and maintain up-to-date threat intelligence to detect potential exploitation attempts.