Investigating unauthorized access to GitHub’s internal repositories

On Monday May 18, we detected and contained a compromise of an employee device involving a poisoned VS Code extension published by a third party. We removed the malicious extension version, isolated the endpoint, and began incident response immediately.

Our current assessment is that the activity involved exfiltration of GitHub-internal repositories only. The attacker’s current claims of ~3,800 repositories are directionally consistent with our investigation so far.

We have no evidence of impact to customer information stored outside of GitHub’s internal repositories, such as our customer’s own enterprises, organizations, and repositories. Some of GitHub’s internal repositories contain information from customers, for example, excerpts of support interactions. If any impact is discovered, we will notify customers via established incident response and notification channels.

We moved quickly to reduce risk. We rotated critical secrets Monday and into Tuesday with the highest-impact credentials prioritized first.

We continue to analyze logs, validate secret rotation, and monitor our infrastructure for any follow-on activity. We will take additional action as the investigation warrants.

We will publish a fuller report once the investigation is complete.

Written by

Alexis Wales

@alexiswales

Alexis Wales is the Chief Information Security Officer of GitHub. She leads a team of security experts focused on safeguarding the GitHub platform, products and the open source community, empowering more than 150 million developers worldwide to build and deploy software securely on GitHub.

Alexis has 20 years of experience defending critical national and private sector networks, spanning positions with the Department of Defense and the Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency (CISA). This experience sparked her passion for collaboration between the public and private sectors to solve the hardest security challenges that threaten the technology we use every day.