CVE-2017-16019 in GitBook
Summary
by MITRE
GitBook is a command line tool (and Node.js library) for building beautiful books using GitHub/Git and Markdown (or AsciiDoc). Stored Cross-Site-Scripting (XSS) is possible in GitBook before 3.2.2 by including code outside of backticks in any ebook. This code will be executed on the online reader.
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Analysis
by VulDB Data Team • 03/21/2023
The vulnerability CVE-2017-16019 represents a stored cross-site scripting flaw in GitBook versions prior to 3.2.2, which poses significant security risks for users relying on this documentation and book-building tool. GitBook serves as both a command line interface and Node.js library that enables users to create books using GitHub repositories and markdown or asciidoc formats. The vulnerability specifically manifests when users include code outside of backticks within ebook content, creating a persistent XSS vector that executes on the online reader platform. This flaw allows attackers to inject malicious scripts that can persistently affect users accessing the content through GitBook's online reader interface, making it particularly dangerous for collaborative documentation environments where multiple users might be exposed to the same compromised content.
The technical implementation of this vulnerability stems from inadequate input sanitization and output encoding within GitBook's processing pipeline for ebook content. When users include code snippets outside of proper markdown backtick delimiters, the system fails to properly escape or sanitize these elements before rendering them in the online reader. This oversight creates a stored XSS condition where the malicious code is permanently embedded in the ebook content and executed whenever any user accesses the document through GitBook's web interface. The vulnerability operates at the application layer and affects the web rendering component of GitBook's online reader, making it a direct threat to user sessions and potentially leading to more severe attacks such as session hijacking or data exfiltration. According to CWE classification, this represents a CWE-79: Cross-site Scripting vulnerability, specifically categorized as a stored XSS variant where the malicious payload is stored on the server and executed during subsequent user interactions.
The operational impact of CVE-2017-16019 extends beyond simple script execution, as it creates persistent security threats for organizations using GitBook for collaborative documentation and knowledge management. When compromised content is published to GitBook's online platform, all users accessing that content become potential victims of the stored XSS attack. The vulnerability particularly affects environments where documentation is shared across teams or organizations, as any user with access to the compromised ebook can become a victim of the malicious code execution. Attackers could exploit this vulnerability to steal user credentials, hijack sessions, or redirect users to malicious websites. The threat is amplified because GitBook's online reader is designed for user interaction, making the execution environment particularly conducive to malicious activity. This vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1566.001 for Phishing, as it enables attackers to establish persistent footholds through compromised documentation content that users willingly access.
Mitigation strategies for CVE-2017-16019 require immediate remediation through upgrading to GitBook version 3.2.2 or later, which includes proper input sanitization and output encoding mechanisms. Organizations should implement content validation policies that enforce proper markdown formatting, particularly requiring code blocks to be properly delimited with backticks to prevent accidental execution of unescaped code. Security teams should establish automated scanning processes to identify and flag potentially malicious code patterns within documentation content before publication. Additional protective measures include implementing content security policies (CSP) at the web application level to restrict script execution and employing web application firewalls to monitor and filter suspicious requests. Regular security audits of documentation repositories should be conducted to identify and remediate any improperly formatted content that might create similar vulnerabilities. The vulnerability underscores the importance of input validation and output encoding practices as outlined in OWASP Top 10 security guidelines, particularly addressing the need for proper sanitization of user-provided content in web applications. Organizations should also consider implementing security awareness training for documentation authors to prevent accidental introduction of XSS vulnerabilities through improper code formatting practices.