CVE-2022-1231 in plantuml
Summary
by MITRE • 04/15/2022
XSS via Embedded SVG in SVG Diagram Format in GitHub repository plantuml/plantuml prior to 1.2022.4. Stored XSS in the context of the diagram embedder. Depending on the actual context, this ranges from stealing secrets to account hijacking or even to code execution for example in desktop applications. Web based applications are the ones most affected. Since the SVG format allows clickable links in diagrams, it is commonly used in plugins for web based projects (like the Confluence plugin, etc. see https://plantuml.com/de/running).
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Analysis
by VulDB Data Team • 04/21/2022
The vulnerability CVE-2022-1231 represents a critical stored cross-site scripting flaw discovered in the PlantUML diagramming tool, specifically affecting versions prior to 1.2022.4. This vulnerability resides within the SVG diagram format processing functionality and stems from inadequate input sanitization when handling embedded SVG content. The flaw allows attackers to inject malicious scripts that persist in the diagram embedder context, creating a stored XSS condition that can be triggered whenever the affected diagram is rendered or viewed.
The technical implementation of this vulnerability exploits the inherent capabilities of SVG (Scalable Vector Graphics) format which supports clickable links and interactive elements through embedded JavaScript. When PlantUML processes diagrams containing SVG content, it fails to properly validate or sanitize user-supplied SVG data, particularly in the context of embedded SVG elements that may contain malicious script tags or event handlers. This processing gap creates an attack surface where malicious SVG code can be stored and subsequently executed in the context of a victim's browser session, particularly when diagrams are displayed within web-based applications or plugins.
The operational impact of CVE-2022-1231 is severe and multifaceted, ranging from data theft to complete account compromise and potential code execution. The vulnerability specifically affects web-based applications that utilize PlantUML plugins, with Confluence plugin being a primary concern as mentioned in the advisory. Attackers can leverage this flaw to steal sensitive information such as API tokens, authentication cookies, or other secrets stored in the browser context. The stored nature of the vulnerability means that once malicious SVG content is uploaded to a repository or shared within a team environment, all users who view the diagram become potential victims of the attack, making it particularly dangerous in collaborative development environments where diagram sharing is common.
The vulnerability aligns with CWE-79 (Cross-site Scripting) and follows patterns consistent with ATT&CK technique T1566.001 (Phishing via Service) and T1059.007 (Scripting: JavaScript). Organizations using PlantUML in web-based environments face significant risk as the attack can be executed through simple diagram uploads that appear legitimate to users. The impact is amplified in desktop applications that may execute PlantUML diagrams, where the potential for code execution exists. The vulnerability affects the core functionality of diagram embedding and rendering, making it particularly dangerous for enterprise environments where diagram collaboration and documentation are integral parts of development workflows.
Mitigation strategies for CVE-2022-1231 require immediate version updates to PlantUML 1.2022.4 or later, which includes proper input sanitization and validation for SVG content. Organizations should also implement additional defensive measures such as content security policy (CSP) headers that restrict script execution in diagram contexts, regular monitoring of diagram repositories for suspicious content, and user education regarding the risks of viewing diagrams from untrusted sources. Network-level filtering and web application firewalls can provide additional protection layers, while administrators should consider implementing automated scanning tools to detect potentially malicious SVG content before it can be stored in repositories. The vulnerability demonstrates the importance of input validation in rich media processing components and highlights the need for comprehensive security testing of diagramming and visualization tools in enterprise environments.