CVE-2018-20241 in FishEye
Summary
by MITRE
The Edit upload resource for a review in Atlassian Fisheye and Crucible before version 4.7.0 allows remote attackers to inject arbitrary HTML or JavaScript via a cross site scripting (XSS) vulnerability in the wbuser parameter.
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Analysis
by VulDB Data Team • 05/11/2020
The vulnerability identified as CVE-2018-20241 represents a critical cross site scripting flaw within Atlassian Fisheye and Crucible platforms prior to version 4.7.0. This security weakness specifically affects the Edit upload resource functionality that handles review-related file uploads, creating an avenue for malicious actors to execute arbitrary code within the context of affected user sessions. The vulnerability manifests through improper input validation of the wbuser parameter, which is utilized during the review editing process when users attempt to upload files or modify existing reviews. Attackers can exploit this weakness by crafting malicious payloads that include HTML or JavaScript code within the wbuser parameter, which then gets executed when other users view the affected review page.
The technical exploitation of this XSS vulnerability occurs because the application fails to properly sanitize or escape user-supplied input before rendering it within the web interface. When the wbuser parameter contains malicious code, the application processes this input without adequate filtering mechanisms, allowing the injected scripts to execute in the browser context of authenticated users. This flaw falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS vulnerability since the malicious content persists in the application's database and affects multiple users who view the compromised review. The vulnerability's impact is amplified by the fact that it occurs within a resource that handles user-generated content, making it particularly dangerous as it can be exploited during normal user interactions with the review system.
The operational implications of this vulnerability extend beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and data exfiltration. An attacker who successfully exploits this vulnerability can potentially steal session cookies, allowing them to impersonate legitimate users and gain unauthorized access to sensitive code repositories, review data, and collaborative workspaces. The vulnerability affects the integrity and confidentiality of the entire Fisheye and Crucible platform, particularly impacting organizations that rely on these tools for code review and collaboration. Given that these tools are commonly used in software development environments, the exploitation could lead to compromise of source code, exposure of sensitive development information, and potential escalation to broader system compromises. The vulnerability also violates security principles outlined in the ATT&CK framework under the T1059.007 technique for Command and Scripting Interpreter, as the malicious code execution enables attackers to perform arbitrary commands within the user context.
Organizations utilizing Atlassian Fisheye and Crucible should prioritize immediate remediation through the application of the vendor-provided security patch for version 4.7.0 or later, which implements proper input validation and output encoding mechanisms to prevent XSS attacks. Additional mitigations include implementing content security policies to restrict script execution, deploying web application firewalls to detect and block malicious payloads, and conducting regular security assessments of user input handling mechanisms. The vulnerability demonstrates the critical importance of input validation in web applications and aligns with security best practices outlined in OWASP Top Ten, specifically addressing the A03:2021-Injection category. Organizations should also consider implementing privileged access management controls and monitoring for suspicious upload activities, as the vulnerability could be leveraged to establish persistent access to development environments. Regular security training for developers and administrators regarding secure coding practices and input sanitization techniques remains essential to prevent similar vulnerabilities from emerging in custom applications or third-party integrations.