CVE-2019-11218 in Bonobo Git Server
Summary
by MITRE
Improper handling of extra parameters in the AccountController (User Profile edit) in Jakub Chodounsky Bonobo Git Server before 6.5.0 allows authenticated users to gain application administrator privileges via additional form parameter submissions.
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Analysis
by VulDB Data Team • 06/02/2020
The vulnerability CVE-2019-11218 represents a critical access control flaw within the Bonobo Git Server authentication system, specifically affecting versions prior to 6.5.0. This issue resides in the AccountController component responsible for user profile management and demonstrates a classic improper input validation weakness that can be exploited to escalate privileges. The vulnerability stems from the server's inadequate handling of form parameters submitted during user profile editing operations, creating a pathway for authenticated users to manipulate the application's authorization logic.
The technical flaw manifests when an authenticated user submits additional form parameters that are not properly sanitized or validated by the AccountController. These extra parameters can contain maliciously crafted values that bypass the normal privilege checking mechanisms, allowing the attacker to assume administrative rights within the Git server environment. The vulnerability directly relates to CWE-284 which describes improper access control, and specifically maps to improper privilege management where the application fails to properly validate user permissions during parameter processing. This weakness enables a privilege escalation attack where a regular user can manipulate the application state through carefully constructed form submissions.
The operational impact of this vulnerability is severe as it allows any authenticated user to gain full administrative privileges within the Bonobo Git Server. This compromise enables attackers to perform actions such as creating new users, modifying existing user permissions, accessing restricted repositories, and potentially gaining access to sensitive source code and development artifacts. The attack vector is particularly concerning because it requires only authentication credentials and does not necessitate additional exploitation techniques or elevated privileges. This vulnerability directly maps to several ATT&CK techniques including privilege escalation and credential access, specifically targeting T1078 for valid accounts and T1068 for additional privileges.
Mitigation strategies for this vulnerability include immediate upgrading to Bonobo Git Server version 6.5.0 or later, which contains the necessary patches to properly validate and sanitize form parameters. Organizations should also implement additional security controls such as input validation at multiple layers, parameterized queries for database operations, and comprehensive logging of user activities to detect anomalous behavior. Network segmentation and access controls should be implemented to limit the potential impact of such vulnerabilities. Regular security assessments and penetration testing should be conducted to identify similar privilege escalation vulnerabilities in the application's authentication and authorization mechanisms. The fix addresses the root cause by implementing proper parameter validation and ensuring that all form submissions are properly authenticated before any privilege modifications are processed.