CVE-2018-5223 in FishEye
Summary
by MITRE
Fisheye and Crucible 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 add a repository in Fisheye or Crucible can execute code of their choice on systems that run a vulnerable version of Fisheye or Crucible on the Windows operating system. All versions of Fisheye and Crucible before 4.4.6 (the fixed version for 4.4.x) and from 4.5.0 before 4.5.3 (the fixed version for 4.5.x) are affected by this vulnerability.
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Analysis
by VulDB Data Team • 01/18/2020
The vulnerability identified as CVE-2018-5223 represents a critical command injection flaw in Atlassian Fisheye and Crucible platforms that specifically targets Windows operating systems. This issue stems from inadequate input validation mechanisms within the Mercurial repository URI handling functionality, creating a pathway for malicious actors to execute arbitrary code on affected systems. The vulnerability is particularly dangerous because it leverages the inherent characteristics of Windows command-line processing where certain characters in URI strings can be interpreted as command arguments rather than literal path components.
The technical flaw manifests when the application processes Mercurial repository URIs that contain special characters such as ampersands, semicolons, or other Windows shell metacharacters. These characters can be interpreted by the Windows command processor as argument separators or command terminators, allowing attackers to inject additional commands that execute with the privileges of the Fisheye or Crucible service account. This type of vulnerability maps directly to CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic example of command injection in enterprise software environments. The vulnerability exists because the software fails to properly sanitize or escape URI components before passing them to underlying system commands.
The operational impact of this vulnerability is severe for organizations running affected versions of Fisheye or Crucible on Windows infrastructure. An attacker with repository addition privileges can escalate their access from a simple repository configuration modification to full system compromise, potentially gaining access to source code repositories, sensitive development data, and underlying infrastructure. This attack vector is particularly concerning in development environments where these tools are commonly used for code review and version control management, as attackers may already have legitimate access to add repositories through normal administrative processes. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting Windows Command Shell execution paths.
Organizations should immediately implement mitigations including upgrading to the fixed versions 4.4.6 and 4.5.3 respectively, as these releases contain proper input validation and sanitization mechanisms. Additionally, network segmentation and access control measures should be enforced to limit who can add repositories to the Fisheye or Crucible instances. The mitigation strategy should also include monitoring for unusual repository addition activities and implementing proper input validation at multiple layers of the application stack. Security teams should also consider deploying web application firewalls and implementing principle of least privilege for the service accounts running these applications to minimize potential impact if exploitation occurs. The vulnerability highlights the importance of proper input validation in enterprise tools that interface with operating system commands, particularly in environments where different operating systems may interpret the same input differently.