Date: Mon, 20 Apr 2015 12:26:29 -0400 (EDT) From: cve-assign@...re.org To: reed@...dloden.com Cc: cve-assign@...re.org, oss-security@...ts.openwall.com Subject: Re: redcarpet <=3.2.2 (and related ruby gems) allow for possible XSS via autolinking of untrusted markdown -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > https://github.com/vmg/redcarpet/commit/e5a10516d07114d582d13b9125b733008c61c242 > http://danlec.com/blog/bug-in-sundown-and-redcarpet > https://hackerone.com/reports/46916 This appears to be a complex situation because of the various codebase relationships, including the relationship between the Sundown/Redcarpet codebase and the site-specific codebase for the hackerone.com website. There's no doubt that there was an interesting bug found (i.e., the "rewind into previous inline" bug) and that the bug had a real-world impact on some Redcarpet users. However, that's not necessarily enough to have a CVE ID. One issue in question is "in the meantime we've hardened our HTML postprocessor, which also eliminates this bug" in the https://hackerone.com/reports/46916#activity-357722 post. This is perhaps similar to what was mentioned about remarkable in the http://openwall.com/lists/oss-security/2015/04/10/10 post. Basically, we're not convinced that anyone should have been relying on Redcarpet as having the security property that it would prevent XSS attacks. In that sense, the "rewind into previous inline" bug would not be categorized as a vulnerability. Apparently hackerone.com had an unspecified HTML postprocessor that might be interpreted as having either some responsibility or all responsibility for preventing XSS attacks. Similarly, in the case of a PHP-based site elsewhere, the overall site design might include both a Markdown implementation and also HTML Purifier. Also, https://github.com/vmg/redcarpet/blob/master/CHANGELOG.md didn't announce 3.2.3 as a security update. We realize that Redcarpet has a :filter_html flag, but the level of focus toward addressing XSS seems small compared to something like HTML Purifier, suggesting different design goals. So, at this point, the available information suggests categorizing https://hackerone.com/reports/46916 as a site-specific problem on hackerone.com and on other sites that were relying on Redcarpet in ways that went beyond the Redcarpet design goals. If there is other information suggesting that the only reasonable interpretation is that it is a Redcarpet vulnerability that must have a CVE assigned against the Sundown/Redcarpet codebase, please let us know. - -- CVE assignment team, MITRE CVE Numbering Authority M/S M300 202 Burlington Road, Bedford, MA 01730 USA [ PGP key available through http://cve.mitre.org/cve/request_id.html ] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (SunOS) iQEcBAEBAgAGBQJVNShAAAoJEKllVAevmvmskmQH/1t19aXHmosS8wHgXMwAqJjj X8NcrZSscNZ3uEM8x5MsigwtoBYOJNGHsQjy06dtse/bNi8EtNiK+e0Kjq6TKMTL +39dI728sBPgstqpSWl8+kKiwe4qysdL/SP+aCp+PO7P36eOpaFGMtg2OE6T1YmO 9cBbR5NzcNTsBG+6+EuHcPm3JJPgZpim5M3tnHc4kO1oq9nC5mlx86f8mPvQZG2c EBi+j5sSt3WodHecTxu8LkCjWdVk0TBkPhx4GuvlyXdt/f/cXxAbLvx4JpM3/DHd efBs+nApiB6ycA7oxZohBEneZaGXL8fgrD+hhQioyZgoth8KcRovV+fqDHLSIl8= =nvFY -----END PGP SIGNATURE-----
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