CVE-2018-7688 in Open Build Service
Summary
by MITRE
A missing permission check in the review handling of openSUSE Open Build Service before 2.9.3 allowed all authenticated users to modify sources in projects where they do not have write permissions.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/27/2025
The vulnerability identified as CVE-2018-7688 represents a critical authorization flaw within the openSUSE Open Build Service platform, specifically affecting versions prior to 2.9.3. This issue stems from a fundamental failure in the system's permission validation mechanisms during the review process, creating a significant security gap that undermines the intended access controls. The openSUSE Open Build Service operates as a distributed build system that manages software packages across multiple projects, making proper access control essential for maintaining system integrity and preventing unauthorized modifications to source code repositories.
The technical flaw manifests in the review handling component where the system fails to perform adequate permission verification before allowing users to modify project sources. This missing permission check occurs during the review workflow, where authenticated users can bypass normal access restrictions and manipulate source files in projects where they lack explicit write permissions. The vulnerability essentially allows privilege escalation through the review process, enabling users to gain unauthorized write access to project repositories. This represents a classic case of insufficient authorization controls, which aligns with CWE-284, specifically addressing improper access control mechanisms that allow users to perform actions beyond their designated permissions.
The operational impact of this vulnerability extends beyond simple unauthorized modifications, as it creates potential for malicious actors or compromised accounts to introduce harmful changes into software projects. Attackers could exploit this flaw to inject malicious code, alter build configurations, or manipulate source dependencies, potentially affecting the entire software supply chain. The implications are particularly severe in environments where multiple teams collaborate on shared projects, as unauthorized modifications could compromise the integrity of builds and introduce security vulnerabilities into production systems. This vulnerability directly violates the principle of least privilege, where users should only have access to resources necessary for their specific roles and responsibilities.
The security implications of CVE-2018-7688 align with several ATT&CK techniques including privilege escalation and defense evasion, as the flaw allows users to bypass normal security controls and potentially hide their activities within legitimate review processes. Organizations using openSUSE Open Build Service versions prior to 2.9.3 were particularly vulnerable to supply chain attacks, where attackers could exploit this weakness to compromise the build environment and potentially affect downstream users. The vulnerability demonstrates the importance of comprehensive access control validation throughout all system workflows, not just at initial authentication points.
Mitigation strategies for this vulnerability include immediate upgrade to openSUSE Open Build Service version 2.9.3 or later, which implements proper permission checks during review operations. Organizations should also conduct thorough access control reviews to identify any other potential authorization gaps in their build systems and implement additional monitoring for suspicious activities during review processes. Security teams should consider implementing automated scanning tools to detect unauthorized modifications and establish clear audit trails for all source code changes. The fix addresses the root cause by ensuring that all review operations perform proper authorization checks before allowing any modifications to project sources, thereby restoring the intended security boundaries within the system.