CVE-2017-9268 in Open Build Service
Summary
by MITRE
In the open build service before 201707022 the wipetrigger and rebuild actions checked the wrong project for permissions, allowing authenticated users to cause operations on projects where they did not have permissions leading to denial of service (resource consumption).
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Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2017-9268 affects the open build service software version prior to 201707022, representing a critical authorization flaw that undermines the security model of the platform. This issue specifically manifests in the wipetrigger and rebuild actions where the system performs incorrect permission validation checks against project access controls. The flaw stems from a misconfiguration in the authorization mechanism that fails to properly verify user permissions before executing sensitive operations on target projects. The open build service operates as a distributed build system where users can submit projects for compilation and testing, making proper access control essential for maintaining system integrity and preventing unauthorized modifications. When users with limited privileges attempt to trigger rebuild operations or wipe project data, the system erroneously grants access based on incorrect project references, effectively bypassing the intended security boundaries.
The technical implementation of this vulnerability involves a flaw in the permission checking logic where the system validates access against the wrong project context during critical operations. This misidentification allows authenticated users to target projects they should not have access to, enabling them to initiate resource-intensive operations that consume system resources without proper authorization. The flaw operates at the application level within the build service's access control framework, specifically affecting the authorization routines that govern project modification and deletion operations. The system's permission model relies on project-specific access controls, but the incorrect validation causes the authorization check to occur against a different project reference than the one being operated upon. This creates a scenario where users can leverage their legitimate access to one project to initiate operations on another project they do not own or have permissions for, effectively circumventing the intended access control mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass significant resource consumption and potential denial of service conditions within the build service environment. Attackers can exploit this flaw to consume excessive system resources through repeated rebuild or wipe operations on target projects, potentially leading to system degradation or complete service unavailability. The vulnerability allows for a form of privilege escalation where users can cause operations on projects they should not have access to, creating a scenario where legitimate users may be unable to access their own projects due to resource exhaustion. The resource consumption aspect particularly affects build servers that handle multiple concurrent operations, as the unauthorized operations can overwhelm system resources and impact performance for all users. This vulnerability directly impacts the availability and reliability of the build service, as malicious actors can intentionally consume resources to disrupt legitimate operations and potentially cause cascading failures in the build infrastructure.
Mitigation strategies for this vulnerability require immediate patching of the open build service to version 201707022 or later, which contains the corrected authorization logic. System administrators should verify that all instances of the build service are updated and that proper access controls are enforced across all project operations. The fix addresses the core authorization flaw by ensuring that permission checks occur against the correct project context rather than an incorrect reference. Organizations should implement monitoring solutions to detect unusual resource consumption patterns that might indicate exploitation attempts, particularly around rebuild and wipe operations. Additionally, access logging should be enhanced to track all project operations and identify unauthorized attempts to access projects. The vulnerability aligns with CWE-284 which describes improper access control issues, and represents a specific implementation of the broader category of authorization bypass flaws. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where attackers leverage system flaws to gain unauthorized access to resources, potentially leading to persistent access and further exploitation opportunities within the build environment.