CVE-2017-18092 in Crucible
Summary
by MITRE
The print snippet resource in Atlassian Crucible before version 4.4.3 (the fixed version for 4.4.x) and before 4.5.0 allows remote attackers to inject arbitrary HTML or JavaScript via a cross site scripting (XSS) vulnerability through the contents of a comment on the snippet.
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Analysis
by VulDB Data Team • 01/06/2020
The vulnerability identified as CVE-2017-18092 represents a critical cross site scripting flaw in Atlassian Crucible software that affects versions prior to 4.4.3 in the 4.4.x release line and before 4.5.0 overall. This vulnerability specifically targets the print snippet resource functionality within the application, which serves as a mechanism for displaying code snippets and associated metadata. The flaw allows remote attackers to inject malicious HTML or JavaScript code through comment fields, creating a persistent vector for exploitation that can compromise user sessions and execute unauthorized actions within the context of the victim's browser.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the comment handling system of Crucible's snippet printing feature. When users submit comments containing malicious payloads, the application fails to properly escape or filter special characters that could be interpreted as HTML or JavaScript code by web browsers. This weakness falls under the common weakness enumeration CWE-79 which specifically addresses cross site scripting vulnerabilities where applications fail to validate or sanitize user-supplied data before incorporating it into dynamically generated web pages. The vulnerability is particularly concerning because it operates at the user interface level where comment fields are rendered in the context of the print snippet functionality, making it accessible to any authenticated user who can submit comments.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it can enable attackers to perform a wide range of malicious activities within the compromised environment. Remote attackers could exploit this flaw to inject malicious scripts that steal session cookies, redirect users to phishing sites, or even modify the content displayed in the snippet viewer. The vulnerability creates a persistent threat vector since comments remain visible to other users and can be exploited repeatedly as long as the vulnerable version remains deployed. This represents a significant concern for organizations using Crucible for code review and collaboration, as the tool is typically used by development teams who may inadvertently interact with malicious content through comment fields. According to ATT&CK framework, this vulnerability maps to T1566 which covers initial access through social engineering and T1059 which involves execution through command and scripting interpreter, as the injected code can execute arbitrary commands within user browsers.
Organizations affected by this vulnerability should immediately implement mitigations including upgrading to the patched versions 4.4.3 or 4.5.0 respectively, as these releases contain proper input validation and output encoding mechanisms to prevent the injection of malicious content. Additionally, administrators should consider implementing web application firewalls that can detect and block suspicious patterns in comment submissions, though this represents a secondary defense measure. The mitigation strategy should also include user education about the risks of interacting with untrusted content and regular security assessments of the application environment. Security teams should monitor for any exploitation attempts through log analysis and implement proper access controls to limit comment submission privileges where possible. The vulnerability demonstrates the critical importance of proper input sanitization in web applications and serves as a reminder that even seemingly benign features like comment systems can become attack vectors when proper security controls are not implemented.