GitHub to Developers: Turn on 2FA or Lose Access

Security experts have been banging the multifactor authentication (MFA) drum for years, encouraging users to move away from solely relying on the username/password combination to secure their most sensitive accounts. Now GitHub is done with encouraging: By the end of 2023, all users who contribute code to GitHub-hosted repositories must have one or more forms of two-factor authentication (2FA) enabled, the company says.

Zero-day attacks and sophisticated exploits are scary, but social engineering and credential theft pose bigger headaches for enterprise defenders. User credentials grant attackers full access to the application and the associated data, or in case of a code repository like GitHub, visibility into source code as well as the ability to maliciously modify the code.

"This places not only the individuals and organizations associated with the compromised accounts at risk, but also any users of the affected code," says Mike Hanley, GitHub's CSO. The downstream effects of an attacker seizing control of a popular code repository is staggering, as "it can be downloaded tens of thousands of times, or hundreds of thousands of times," he says.

Attacks against the software supply chain jumped by more than 300% in 2021, Aqua Security said in January.

GitHub’s decision increases the complexity of account takeovers, says Andrew Hay, COO at LARES Consulting. "It has been proven time and time again that multifactor authentication provides an additional layer of protection to a user's account without exponentially complicating the login process," he says.

Raising the Bar
Considering the sheer number of developers and active repositories on GitHub.com, this move has the potential to significantly enhance the security of the software supply chain. The company says the shift to 2FA will impact 83 million developers.

Hanley has said in the past that GitHub’s sheer size puts the company in a strong position to boost the security of the entire software ecosystem. By implementing new security features, GitHub is raising the bar on things developers and project maintainers have to do.

"Strong password management, privileged access security, and MFA will make it difficult for attackers to be successful at gaining an initial foothold," says Joseph Carson, chief security scientist and advisory CISO at Delinea. "This will likely force them to look for an easier target elsewhere."

Move to Mandatory Enrollment
GitHub has offered 2FA in some form since 2013. Recognizing that attackers are increasingly targeting JavaScript packages on the npm registry, GitHub enrolled all the maintainers of the top 100 npm packages with mandatory 2FA back in February. Even so, adoption has lagged. Currently, only 16.5% of active GitHub users and 6.44% of npm users have enabled one or more forms of 2FA on their accounts, the company says.

The numbers are dismal but not wholly unexpected. Back in 2018, Google noted that seven years after introducing 2FA for Gmail, less than 10% of active accounts had enabled the feature. More than three-quarters (78%) of organizations with Microsoft Active Directory (AD) currently do not employ MFA for their user accounts, Microsoft said in its quarterly Cyber Signals report earlier this year. Microsoft has said repeatedly that "99.9% of breaches would be prevented if you just implemented MFA."

GitHub has taken other steps to improve security beyond relying on just the username and password. Earlier, GitHub deprecated basic authentication for Git operations and GitHub’s REST API, and now require email-based device verification. Since March, all npm accounts require enhanced login verification. The company launched 2FA for GitHub Mobile on iOS and Android back in January.

GitHub will allow multiple methods, including hardware security keys and mobile push notifications approved directly from the GitHub app.

GitHub already gives enterprise customers the ability to require developers to use 2FA to access enterprise repositories. When enforcement takes effect, there may be some issues if GitHub winds up removing users who do not have 2FA enabled from enterprise repositories, Hay notes. "It may lead to some calls to the support desk if a user finds that they can no longer access the code repositories they once had access to," he says.

Delayed Enforcement
The shift to mandatory 2FA will occur in phases. All maintainers of the top 500 packages will be enrolled in mandatory 2FA on May 31. Maintainers of high-impact npm packages — which GitHub defined as those with more than 500 dependents or one million weekly downloads — will be enrolled in mandatory 2FA in the third quarter of 2022. The long lead time — more than a year out — will help GitHub "make sure we get this right" in terms of ensuring the user experience with the command line and the web interface, Hanley says.

Carson notes that recent advancements have made MFA "far less burdensome" to users. The most common mistake in enterprise deployments is to add MFA to existing authentication schemes rather than strengthening (and potentially replacing) them. MFA should be used to make logging in more efficient, as well as more secure.

"It is important to make authentication easier and the experience positive where possible," Carson says. "Otherwise users will find ways around the security control making them much weaker."