While preparing the last Horde 3 maintenance release in February 2012 the Horde developers discovered that hackers breached the security of the Horde FTP server and managed to place a backdoor into three of the distributed packages. The attack had taken place in November the year before so that the modified packages were distributed over three months. One of the tainted packages was picked up by the unstable branches of Debian and Ubuntu and were fixed immediately after the successful attack was disclosed. The attackers did not modify the newer Horde 4 sources.