Backdoors are events on 2b2t when a player, or a group of players, bypass the server's normal operations to gain access to exploits in which the particular players can abuse. Currently, there have been three major backdoors in 2b's history. All these backdoors have been patched by Hausemaster.
First Backdoor (popbob's Reign of Terror)
The first major backdoor of 2b2t, also known as the Dark Times and popbob's Reign of Terror, has had two intervals. The first interval of the backdoor began sometime in December of 2011 and ended in January of 2012. Popbob, during this first interval of the backdoor, he had permissions to use the "TooManyItems" mod, which he gave to many of his fellow Facepunchers, including xcc2, policemike55, and others. This access to TooManyItems mode and the backdoor allowed for the creation of Ziggy Town's bedrock comet and Plugin Town. Hause eventually ended this backdoor interval by removing popbob's access to some of his powers and permissions. Popbob also used his backdoor access to create hacked items. Eventually, the backdoor was patched by Hausemaster, disabling thunder from 2b2t for more than five years in the process.
Second Backdoor (The Arms Race)
The second major backdoor of 2b2t occurred during December of 2013. The backdoor involved iTristan and Pyrobyte designing a plugin to block access to the nether roof. The backdoor has two major features, the ability to spawn hacked items such as player heads and 32K weapons, and allowed travel on the nether roof if the player was riding a horse.
They also used it to get to the world border. The 2b2t Arms Race, alwas a time period in 2b2t history that lasted for 3 years, from December of 2013 during the First Valkyrian Period and ended in the spring of 2016, during the Pre-Hype Period, right before The Age of Hype. This event was a large scale search for the ominous super weapons created by Pyrobyte and iTristan during the second backdoor of 2b2t.
Third Backdoor (The Hacked Account Crisis)
The third major backdoor was probably the most severe backdoor to this date and occurred sometime during the end of 2015 and ended in April 2016. The backdoor involved the hacking of georgebush420's OP (operator - full perms) account due to database leaks. The Tyranny used the account to grief bases, and create more hacked items. The backdoor was patched when Hause and George gained the account back. Many players either migrated to Constantiam or left the server entirely due to the chaos caused by the backdoor and the /tell exploit. The large exodus of players was so severe that at points the server would have as little as one or no players online. The exodus was somewhat reversed by the 2b2t video by TheCampingRusher, and subsequently the 4th Incursion.
Cause Of Backdoors
The first two backdoors were caused by Hausemaster using player designed plugins to fix issues on the server. These players would obviously add in code to give themselves access to a backdoor of the server once Hause implemented the plugin. In the case of the third major backdoor, the Tyranny, the group instead managed to get the login credentials of an OP account through a Chinese database leak.