CVE-2023-33962 in JStachio
Summary
by MITRE • 05/31/2023
JStachio is a type-safe Java Mustache templating engine. Prior to version 1.0.1, JStachio fails to escape single quotes `'` in HTML, allowing an attacker to inject malicious code. This vulnerability can be exploited by an attacker to execute arbitrary JavaScript code in the context of other users visiting pages that use this template engine. This can lead to various consequences, including session hijacking, defacement of web pages, theft of sensitive information, or even the propagation of malware.
Version 1.0.1 contains a patch for this issue. To mitigate this vulnerability, the template engine should properly escape special characters, including single quotes. Common practice is to escape `'` as `'`. As a workaround, users can avoid this issue by using only double quotes `"` for HTML attributes.
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Analysis
by VulDB Data Team • 06/24/2023
The vulnerability identified as CVE-2023-33962 affects JStachio, a type-safe Java Mustache templating engine designed to provide secure template processing for web applications. This issue represents a classic cross-site scripting vulnerability that arises from inadequate input sanitization within the template rendering process. The flaw specifically manifests when the engine processes HTML content without proper escaping of single quotation marks, creating an avenue for malicious code injection that can compromise user sessions and data integrity.
The technical implementation of this vulnerability stems from JStachio's failure to properly sanitize template variables before rendering them into HTML contexts. When template data containing single quotes is processed, the engine does not escape these characters, allowing attackers to break out of HTML attribute contexts and inject malicious JavaScript code. This behavior aligns with CWE-79, which defines Cross-Site Scripting vulnerabilities as the result of insufficient escaping of output content. The vulnerability exists at the intersection of template engine security and HTML context handling, where the engine should automatically escape special characters to prevent injection attacks.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to perform sophisticated session hijacking operations by injecting malicious scripts that can capture user credentials or session tokens. Web page defacement becomes possible through the injection of malicious HTML content that can modify page appearance or functionality. The vulnerability also poses significant risks for data theft, as attackers can craft payloads that exfiltrate sensitive information from users' browsers. Furthermore, the compromised systems can serve as launch points for malware propagation, potentially affecting entire user bases that visit pages utilizing vulnerable templates. This vulnerability directly maps to ATT&CK technique T1566, which covers social engineering through malicious content injection.
The remediation approach for CVE-2023-33962 involves updating to JStachio version 1.0.1, which implements proper escaping of special characters including single quotes. The patch should ensure that single quotes are properly escaped as ' or ' when rendering template content into HTML contexts. Organizations can also implement additional protective measures such as Content Security Policy headers to limit script execution capabilities, though the primary mitigation remains the proper escaping implementation. The workaround of using only double quotes for HTML attributes provides a temporary solution but does not address the root cause and should be considered a stopgap measure until the official patch is deployed. Security teams should conduct comprehensive testing to ensure that all template usage patterns properly handle this escaping requirement, particularly in environments where user-supplied data is processed through the templating engine.