Fixed XDPF Rewriting for multiple hashtags in URL (Resolved) Investigating / Notice
16 days

On Tuesday, November 19th, 2019 we addressed a bug in the ExchangeDefender Phishing Firewall URL rewriting software that was improperly truncating URLs. Our partners at ReadyCrest Ltd identified the bug by comparing the length of the compressed, rewritten and raw URL and seeing that we truncate link after the first #.Usage of # tends to be fairly explicit in HTML emails and almost exclusively used for anchor links. These links don't actually connect to another site/document, they are meant to scroll the browser to a specific part in the web page. Typically they are used in a table of contents for longer pages, contracts, etc to move the browser to where the actual content is. The syntax is # followed by the name of the section to scroll to - so there is NO functional reason in HTML to ever have more than one # in the URL. That was key in our design and decision to drop anything past the second # - but we've now discovered that some sites may, in fact, put extra (typically reserved) special characters like # in the URL which breaks ExchangeDefender Phishing Firewall rewrites because it removes portions of the link.To our knowledge, this is the first reported link with multiple # in the URL, and going forward multiple # will be allowed in the URL without truncation.This issue has been addressed.