CVE-2021-43201 in TeamCity
Summary
by MITRE • 11/09/2021
In JetBrains TeamCity before 2021.1.3, a newly created project could take settings from an already deleted project.
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Analysis
by VulDB Data Team • 11/12/2021
This vulnerability in JetBrains TeamCity affects versions prior to 2021.1.3 and represents a critical configuration management flaw that enables unauthorized data leakage and potential privilege escalation. The issue arises from improper handling of project creation logic where newly instantiated projects can inadvertently inherit or reference settings from previously deleted projects, creating a persistent security risk that extends beyond the intended scope of project isolation.
The technical flaw stems from inadequate validation during project initialization processes where the system fails to properly sanitize or reset project configuration parameters when creating new instances. This allows the new project to access or reference configuration elements that should have been permanently removed, effectively creating a data persistence vulnerability. The vulnerability manifests as a configuration inheritance mechanism that bypasses normal access controls and project lifecycle management protocols, enabling unauthorized access to potentially sensitive project settings and configurations.
Operationally, this vulnerability can have severe consequences for organizations relying on TeamCity for continuous integration and deployment processes. An attacker with access to create new projects could potentially extract sensitive information from deleted projects including build scripts, environment variables, credential references, and other configuration data that should have been permanently removed. The impact extends beyond simple information disclosure to potential privilege escalation scenarios where attackers might leverage inherited settings to gain elevated access within the system. This flaw particularly affects environments where project deletion is used as a security measure to isolate sensitive build processes and where proper access controls are expected to prevent cross-project information leakage.
The vulnerability aligns with CWE-200, which addresses improper information disclosure, and CWE-264, which covers permissions, privileges, and access controls. From an ATT&CK framework perspective, this issue maps to T1078 legitimate credentials and T1566 credential access, as it enables unauthorized access to project configurations that may contain sensitive authentication information. Organizations should implement immediate mitigations including upgrading to TeamCity version 2021.1.3 or later, implementing strict access controls for project creation operations, and conducting thorough audits of project configurations to identify any potential inherited settings from previously deleted projects.
Mitigation strategies should focus on enforcing proper project lifecycle management, implementing automated checks during project creation to prevent configuration inheritance from deleted projects, and establishing monitoring procedures to detect unauthorized project creation activities. Security teams should also consider implementing additional layers of access control and privilege management to minimize the potential impact of such vulnerabilities. Regular security assessments of configuration management systems and continuous monitoring of project creation and deletion activities are essential to prevent exploitation of similar vulnerabilities in the future.