CVE-2018-5224 in Bamboo
Summary
by MITRE
Bamboo did not correctly check if a configured Mercurial repository URI contained values that the Windows operating system may consider argument parameters. An attacker who has permission to create a repository in Bamboo, edit an existing plan in Bamboo that has a non-linked Mercurial repository, or create a plan in Bamboo either globally or in a project using Bamboo Specs can can execute code of their choice on systems that run a vulnerable version of Bamboo on the Windows operating system. All versions of Bamboo starting with 2.7.0 before 6.3.3 (the fixed version for 6.3.x) and from version 6.4.0 before 6.4.1 (the fixed version for 6.4.x) running on the Windows operating system are affected by this vulnerability.
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Analysis
by VulDB Data Team • 01/18/2020
This vulnerability in Atlassian Bamboo represents a critical command injection flaw that arises from insufficient input validation when processing Mercurial repository URIs on Windows systems. The vulnerability stems from the application's failure to properly sanitize user-supplied URI parameters, allowing malicious actors to inject command-line arguments that the Windows operating system interprets as executable commands. This occurs specifically when Bamboo processes repository URIs that contain specially crafted parameters which Windows treats as command arguments rather than simple path components, creating an avenue for arbitrary code execution.
The technical implementation of this vulnerability leverages the Windows command processing behavior where certain characters and parameter patterns in URI strings can be interpreted by the operating system as command-line arguments. When Bamboo executes Mercurial commands on Windows systems, it passes these unvalidated URI parameters directly to the underlying system commands without proper sanitization or escaping mechanisms. This design flaw enables attackers to inject malicious commands that get executed with the privileges of the Bamboo service account, potentially leading to complete system compromise.
The operational impact of this vulnerability is severe and far-reaching, particularly for organizations running Bamboo on Windows infrastructure. Attackers with minimal permissions can escalate their privileges to execute arbitrary code on target systems, potentially gaining access to sensitive build artifacts, source code repositories, and underlying infrastructure. The vulnerability affects multiple versions of Bamboo including 6.3.x versions prior to 6.3.3 and 6.4.x versions prior to 6.4.1, making it a widespread concern for organizations maintaining these specific software versions. The attack vector is particularly dangerous because it requires only basic permissions to create or modify repository configurations, making it accessible to both internal and external threat actors.
From a cybersecurity perspective, this vulnerability maps directly to CWE-78, which describes improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The vulnerability demonstrates a classic path traversal and command injection pattern where user input flows directly into system execution contexts without proper validation or sanitization. Organizations should implement immediate mitigations including upgrading to patched versions of Bamboo, implementing strict input validation for repository URIs, and applying network segmentation controls to limit access to Bamboo servers. Additionally, security teams should monitor for suspicious repository configuration changes and implement automated scanning for similar input validation flaws in other continuous integration systems.
The remediation approach requires organizations to prioritize patch management for affected Bamboo versions while implementing defense-in-depth strategies. The vulnerability highlights the importance of validating all user inputs that flow into system commands, particularly in cross-platform applications that execute on multiple operating systems with different security characteristics. Organizations should also consider implementing runtime application self-protection mechanisms and regular security assessments to identify similar input validation weaknesses in their software ecosystems. This vulnerability serves as a critical reminder of the importance of proper input sanitization and the potential consequences of inadequate security controls in build and deployment systems.