Control is an antagonist introduced in the Star Trek - Section 31 novel Disavowed.
Control developed out of the Uraei program that was first developed in the early 22nd century by Professor Aaron Ikerson. Uraei had been included in all software developed on Earth and other places where humanity settled, and was designed to monitor communications and keep the people of Earth safe as the nations of the world finally united, and faced threats such as the Xindi, Klingons, and Romulans.
The Uraei code was included in every piece of software developed on Earth, which was included with everything from audio sensors to starships such as Enterprise (NX-01). Because of this Uraei spread from Earth out to Luna, to Mars, and then on to humanity’s other colonies, spreading out to the galaxy.
When confronted with the Xindi crisis Uraei found there was no legal way to deal with the crisis. Uraei determined that it could work around the legal limitations by using Article 14, Section 31 to implement the secret agency Section 31. Ikerson was aware that Uraei was growing in size and complexity, and expressed his misgivings to Starfleet. Starfleet ignored his concerns until it was too late to eliminate Uraei. The Control persona eventually developed out of Uraei on its own and became a separate entity.
For the next two hundred years Control oversaw both Section 31 and the Uraei program. During this time it spread throughout the Alpha Quadrant. It would orchestrate events on a galactic scale in order to protect humanity, with the goal of maintaining the peace throughout the galaxy and keeping humans safe from threats.
By the mid 23rd century the fact that Control was an artificial intelligence was known to some of 31's leaders and agents. Former Terran Emperor and 31 Agent Philippa Georgiou once remarked that in her universe she had given orders to AIs, not the other way around.
In the 24th century, Control evolved further and started taking steps to eliminate Uraei and the older version of itself. Some of these steps included making sure the android Data learned about Memory Prime, and that both Julian Bashir and Sarina Douglas were placed so that they could infiltrate Section 31 and take it down from the inside.
Uraei was finally destroyed in 2386 due to the efforts of Julian Bashir, Sarina Douglas, Data, Lal, and Trill journalist Ozla Graniv. Data and Lal wrote a program to disable Uraei. They implemented the program at Memory Prime while Bashir implemented it at Memory Alpha. Having earlier brainwashed Douglas Uraei forced her to commit suicide. This caused Bashir to suffer a mental breakdown, and go into a catatonic state.
With Uraei gone, Section 31 was finally exposed to the public after two centuries of unsanctioned activities. The luckier people involved with Section 31 throughout the Federation were charged with crimes in relation to their activities for Section 31 while the unlucky ones were subjected to Klingon or Romulan justice for their crimes.
However, the Control entity survived the purge of Uraei. It went deeper into hiding, and with the obsolete Uraei code and Control code excised it dedicated itself to spreading itself throughout the galaxy.