CVE-2018-5227 in Application Links
Summary
by MITRE
Various administrative application link resources in Atlassian Application Links before version 5.4.4 allow remote attackers with administration rights to inject arbitrary HTML or JavaScript via a cross site scripting (XSS) vulnerability in the display url of a configured application link.
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Analysis
by VulDB Data Team • 01/23/2020
The vulnerability identified as CVE-2018-5227 represents a critical cross site scripting flaw within Atlassian Application Links component affecting versions prior to 5.4.4. This vulnerability specifically targets the administrative application link resources where unauthenticated attackers with administrative privileges can exploit the system to inject malicious HTML or JavaScript code. The flaw exists in the display url handling mechanism of configured application links, creating a pathway for persistent malicious code execution within the administrative interface. The vulnerability operates through the improper sanitization of user-supplied input during the rendering of application link display urls, allowing attackers to manipulate the interface and execute arbitrary code in the context of the victim's browser session.
The technical exploitation of this vulnerability occurs when administrators configure application links within Atlassian products, particularly in environments where multiple applications are integrated through the Application Links framework. Attackers with administrative access can craft malicious URLs containing script payloads that get rendered in the application link display fields. When other administrators or users view these configured links, the injected JavaScript executes in their browser context, potentially leading to session hijacking, data exfiltration, or further privilege escalation within the Atlassian ecosystem. This vulnerability directly maps to CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is used in a web page without proper validation or escaping, and aligns with ATT&CK technique T1059.007 for Scripting through the execution of malicious JavaScript code within legitimate web applications.
The operational impact of CVE-2018-5227 extends beyond simple code injection as it can enable attackers to gain persistent access to administrative interfaces and potentially compromise entire Atlassian product installations. Organizations using affected versions face significant risk of unauthorized access to sensitive configuration data, user credentials, and system information. The vulnerability is particularly dangerous because it requires only administrative privileges to exploit, meaning that attackers who have already gained administrative access to Atlassian applications can use this flaw to escalate their privileges further or maintain persistent access. The attack vector is relatively straightforward as it involves modifying existing application link configurations, making it difficult to detect through normal security monitoring. The affected systems include various Atlassian products such as Jira, Confluence, and Bamboo, all of which rely on the Application Links framework for integration purposes, making the potential attack surface quite broad within enterprise environments.
Organizations should immediately upgrade to Atlassian Application Links version 5.4.4 or later to remediate this vulnerability, as the patch addresses the core issue of insufficient input sanitization in the display url handling process. Security teams should implement comprehensive monitoring for unauthorized changes to application link configurations and establish strict access controls for administrative functions. Additionally, organizations should conduct thorough security reviews of all application link configurations and implement content security policies to mitigate potential exploitation. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, particularly within administrative interfaces where elevated privileges can be leveraged for maximum impact. Regular security assessments of integrated application environments are essential to prevent similar vulnerabilities from being exploited in other components of the Atlassian ecosystem.