Added data: and vbscript: link fix to prevent XSS vulnerability #63
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Thanks! This looks great. I’ll deploy a version with these changes later today |
ariabuckles
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Mar 14, 2019
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Published simple-markdown@0.4.4 with these changes. Thanks again! |
ariabuckles
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May 21, 2020
I believe this fixes https://www.npmjs.com/advisories/1219 if `options.disableParsingRawHTML` is set. NOTE: This does not handle script elements, etc., that may be rendered when `options.disableParsingRawHTML` is not enabled. We might be able to use something like [`dompurify`](https://github.com/cure53/DOMPurify) to solve that case? According to https://owasp.org/www-community/xss-filter-evasion-cheatsheet , the dangerous `javascript:` protocol can contain some whitespace characters and still be vulnerable, and sometimes when used in conjunction with images, some other special characters like ` or < before the javascript: protocol can also leave a url vulnerable. This change re-adds the sanitiation logic removed in 9c6c782 , and also adds the vbscript/data handling from github.com/ariabuckles/simple-markdown/pull/63 Test plan: Add tests and run `npm test`
ariabuckles
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May 22, 2020
I believe this fixes https://www.npmjs.com/advisories/1219 if `options.disableParsingRawHTML` is set. NOTE: This does not handle script elements, etc., that may be rendered when `options.disableParsingRawHTML` is not enabled. We might be able to use something like [`dompurify`](https://github.com/cure53/DOMPurify) to solve that case? According to https://owasp.org/www-community/xss-filter-evasion-cheatsheet , the dangerous `javascript:` protocol can contain some whitespace characters and still be vulnerable, and sometimes when used in conjunction with images, some other special characters like ` or < before the javascript: protocol can also leave a url vulnerable. This change re-adds the sanitiation logic removed in 9c6c782 , and also adds the vbscript/data handling from github.com/ariabuckles/simple-markdown/pull/63 Test plan: Add tests and run `npm test`
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Cross-site Scripting (XSS) via Data or Vbscript URIs.
The following markup
[link](data:text/html;base64,PHNjcmlwdD5hbGVydCgnaGknKTwvc2NyaXB0Pg==)produces<script>alert('hi')</script>.