On December 29, 2022, Slack was alerted to suspicious activity on their GitHub account. Upon investigation, the company discovered that a limited number of employee tokens had been stolen and misused to gain access to an externally hosted repository. The threat actor had also downloaded private code repositories on December 27, but neither Slack’s primary codebase nor any customer data were included in the downloaded repositories.

Upon being notified of the incident, Slack immediately invalidated the stolen tokens and began an investigation into the potential impact on their customers. It was determined that the threat actor did not access other areas of Slack’s environment or customer data. There was no impact on Slack’s code or services, and the company rotated all relevant credentials as a precautionary measure.

According to Slack’s investigation, the unauthorized access did not result from a vulnerability inherent to the company’s systems. They will continue to monitor for further exposure and investigate the incident further.

This security breach serves as a reminder of the importance of strong authentication measures, particularly when it comes to APIs that may have access to sensitive data. It also highlights the need for companies to regularly review and update their security protocols in order to prevent unauthorized access.

At a time when data breaches and cyber attacks are becoming increasingly common, it’s more important than ever for companies to prioritize security. This includes implementing multi-factor authentication (MFA), regularly rotating credentials, and staying vigilant for suspicious activity.

In this case, the theft and misuse of Slack employee tokens likely occurred through an API, highlighting the need for strong authentication measures to protect against unauthorized access.

API keys, which are used to authenticate API requests, are a particularly attractive target for threat actors due to the potential access they provide. If an API key is compromised, it can allow an attacker to gain access to sensitive data or potentially even take control of an entire system - and it can be particularly difficult to fully remediate this kind of compromise. That’s why it’s crucial for companies to properly secure their API keys and regularly rotate them as a precautionary measure.

In the case of Slack, it’s not yet clear exactly how the employee tokens were stolen and misused. However, the incident serves as a reminder of the importance of API security and the potential consequences of API keys leaks. By taking the necessary precautions and implementing strong authentication measures, companies can better protect themselves and their customers from potential threats.