In a statement issued at 7pm AEDT on Thursday, the company said depending on the broadcast software used, streamers would need to install an update in order to start their next streams.
News of the leak was posted on the 4chan website and security researcher Troy Hunt released a list of the files leaked on GitHub, as iTWire reported on Thursday.
It said: "Depending on which broadcast software you use, you may need to manually update your software with this new key to start your next stream:
"OBS users who have connected their Twitch account should also not need to take any action. OBS users who have not connected their Twitch account to OBS will need to manually copy their stream key from their Twitch Dashboard and paste it into OBS.
Out of an abundance of caution, we have reset all stream keys. You can get your new stream key here: https://t.co/Lby1wfS0Ss. For more information, please visit the Twitch blog: https://t.co/JDXlpO0pY4— Twitch (@Twitch) October 7, 2021
"For all others, please refer to specific setup instructions for your software of choice."
In an earlier statement issued on Wednesday at 4.30pm AEDT, the company acknowledged that the incident had occurred.
"We have learned that some data was exposed to the Internet due to an error in a Twitch server configuration change that was subsequently accessed by a malicious third party," it said.
"At this time, we have no indication that login credentials have been exposed.
"Additionally, full credit card numbers are not stored by Twitch, so full credit card numbers were not exposed."
Commenting on the incident, Ashwin Ram, a cyber security expert from the Office of the CTO at Check Point Software, said: “Any time source code gets leaked it’s not good and potentially disastrous.
"It opens a gigantic door for evil doers to find cracks in the system, lace malware, and potentially steal sensitive information.
"I strongly recommend all Twitch users exercise caution in the near term ahead as cyber attacks are on the rise. For October’s Cyber Security Awareness month, Check Point Research documented a 40% increase in cyber attacks this year, compared to 2020.
"For now, we recommend Twitch users change their passwords and enable two-factor authentication on accounts.”