Horde is groupware, available for free via web browsers. Its components rest on Horde’s PHP-based framework, which delivers elements crucial to the fast development of web applications.
The range of applications available through Horde includes: the Horde IMP email client; time software for tracking tasks; a wiki; and a package comprising notes, calendar, tasks and a file manager.
The framework started as the Internet Messaging Project (IMP) webmail published on Freshmeat by Chuck Hagenbuch, way back in 1998. However, constant feature requests (many of which were unsuitable for a webmail application) necessitated the development of a web app backbone that was more generic.
Version 1.3.3. of the Horde framework was announced on Freshmeat at the start of 2001, which was followed by Horde 2.0 and IMP 3.0 (the first with two completely separate components).
As a generic web app framework, Horde mainly provided support for webmail, but with Horde 3.0’s release in 2004, it also became a groupware application set. Its flexible, modular structure enabled numerous service providers and packagers to add this software into their own portfolios with ease.
Horde is utilized for webmail provided by SAPO, serving millions of users, and the software has been packaged for every main Linux distribution. Also, it can be found as a component in such hosting tools as cPanel or Plesk.
Horde 4.0’s 2011 release introduced substantial architectural changes, support for mobile devices, and a breakdown into almost 100 PEAR packages.
However, one of the most notable events in Horde’s history occurred in early 2012, as the final Horde 3.0 maintenance release was undergoing preparation. Developers realized that hackers had managed to break through the FTP server’s security and implemented a backdoor into multiple distributed packages.
It was believed this previously-undetected attack had occurred a few months earlier. Eventually, one of the packages tained was picked up by Debian and Ubuntu’s Unstable branches, before being fixed quickly once the attack had been disclosed. The hackers made no modifications to the Horde 4 sources, though.