CVE-2018-20240 in FishEye
Summary
by MITRE
The administrative linker functionality 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 href parameter.
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Analysis
by VulDB Data Team • 05/11/2020
The vulnerability identified as CVE-2018-20240 represents a critical cross site scripting flaw within Atlassian Fisheye and Crucible platforms prior to version 4.7.0. This issue specifically targets the administrative linker functionality, which serves as a critical component for managing external references and connections within the software ecosystem. The vulnerability manifests when the system fails to properly sanitize user input provided through the href parameter, creating an avenue for malicious actors to inject arbitrary HTML or JavaScript code into the application's response. This flaw exists within the web application's input validation mechanisms, allowing attackers to bypass security controls that should normally prevent untrusted data from being executed as code within the browser context of authenticated users.
The technical exploitation of this vulnerability occurs through the manipulation of the href parameter within the administrative linking interface. When administrators or users interact with the affected functionality, the application processes the provided href value without adequate sanitization or encoding, enabling malicious payloads to be stored or executed. This represents a classic reflected XSS vulnerability where the malicious input is immediately reflected back to the user's browser without proper context-aware escaping or validation. The vulnerability falls under CWE-79 which specifically addresses cross site scripting flaws in web applications, and aligns with ATT&CK technique T1203 which describes the exploitation of web application vulnerabilities to gain unauthorized access or execute malicious code. The flaw particularly affects the administrative capabilities of the platform, potentially allowing attackers to escalate privileges or compromise the integrity of the entire system through user session hijacking or data exfiltration.
The operational impact of this vulnerability extends beyond simple code injection, as it can enable attackers to perform various malicious activities within the context of the affected application. An attacker could leverage this vulnerability to steal administrative session cookies, redirect users to malicious sites, or inject malicious scripts that could exfiltrate sensitive data from the Fisheye and Crucible environment. The administrative nature of the affected functionality means that successful exploitation could lead to complete compromise of the platform, potentially allowing attackers to modify repository configurations, access restricted code repositories, or manipulate the integration points that these tools provide for software development workflows. Organizations relying on these platforms for code review, version control integration, and collaborative development environments face significant risk if this vulnerability remains unpatched, as it could serve as a foothold for broader attacks against their software development infrastructure.
Mitigation strategies for CVE-2018-20240 should prioritize immediate patching of affected systems to version 4.7.0 or later, which includes proper input sanitization and output encoding for the href parameter in the administrative linking functionality. Organizations should implement additional defensive measures including web application firewalls that can detect and block suspicious input patterns, input validation rules that prevent HTML and JavaScript code from being accepted in administrative parameters, and regular security scanning of the application's administrative interfaces. Network segmentation and least privilege access controls should be enforced to limit the potential impact of successful exploitation, while security monitoring should be enhanced to detect unusual administrative activities or unexpected data flows from the affected components. The vulnerability serves as a reminder of the critical importance of proper input validation and output encoding in web applications, particularly within administrative interfaces where the potential for privilege escalation and system compromise is significantly elevated.