Shai Hulud 2.0 has struck again, launching a malware supply-chain attack that has left many in the mobile app development community on high alert. The latest wave of attacks targets npm packages, spreading quickly and stealthily through compromised developer environments.

Timeline of the Shai-Hulud Campaign

The timing of this attack is particularly noteworthy, given npm's recent announcement to revoke classic tokens on December 9 after a series of supply-chain attacks. With many users still not migrated to trusted publishing, the attacker seized the moment for one more hit before npm's deadline.

  • August 27: Our report detailing the S1ngularity campaign targeting several nx packages on npm was released.
  • September 16: The attacker struck again, launching the first wave of Shai-Hulud attacks.
  • September 18: We published a follow-up analysis, diving deeper into the campaign's technical quirks and early payload behavior.
  • November 24: A second strike occurred, dubbed the "Second Coming" by the attackers, timed just before npm's deadline for revoking old tokens.

What is Shai-Hulud?: A Quick Refresher

Shai-Hulud is a self-replicating npm worm built to spread quickly through compromised developer environments. Once it infects a system, it searches for exposed secrets such as API keys and tokens using TruffleHog and publishes anything it finds to a public GitHub repository. It then attempts to push new copies of itself to npm, helping it propagate across the ecosystem, while exfiltrating data back to the attacker.

Differences from Last Time

This time around, there are some significant differences in the attack:

  • It installs bun with the file setup_bun.js and then uses that to execute bun_environment.js, which is the actual malicious code.
  • It creates a randomly named repository with stolen data, rather than a hardcoded name.
  • It will infect up to 100 npm packages, compared to 20 last time.
  • If it can't authenticate with GitHub or NPM, it will wipe all files in the user's Home directory.

Leaking Secrets

This time, the malware also publishes secrets to GitHub, with a random name and the repository description: "Shai-Hulud: The Second Coming." Currently, we see 26.3k repositories exposed.

Mistakes Made Again

As we've been analyzing all these packages, we've noticed a number of compromised packages that appear to be from community spread, which contain the initial staging code in setup_bun.js, but NOT the Shai Hulud worm itself. Here's the code that spreads the worm into other packages:

... (code snippet)

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