During the night of July 31 to August 1, many servers, using the time synchronization protocol NTP (Network Time Protocol), began to report the discovery of another "extra" second. Although an official warning on the introduction of leap second was not distributed. Users of Linux-systems informed of failures which occurred due to the addition of extra second. Messages appeared in Twitter, Google + and NTP project's mailing lists.
Experts claim that leap second spread between NTP-servers. The source of the bogus leap second was one of the primary NTP-servers, but its location is still not established.
Some experts believe that the bogus leap second may be the result of DoS-attacks on the Linux-based systems, which were operating without being updated. Others say that the error was caused by the fact that some servers hadn’t added the leap second during the night of June 30 to July 1, that’s why the procedure was repeated a month later.
