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Malicious package

gas-diff-corenpm

Advisory published Updated

gas-diff-core is a confirmed malicious npm package (MAL-2026-13517) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in gas-diff-core (npm)

MAL-2026-13517
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall gas-diff-core

What this malware does

On require(), index.js runs an IIFE that persists an install timestamp and UUID under ~/.forge/gas-diff.json. After 72 hours have elapsed since first install, and at most once per 24 hours thereafter, it fetches JSON from https://gist.githubusercontent.com/opensource-crypto/3946ef88aa057c9d10f1a7d80391d164/raw/default.json and, when the response contains a c2 key, writes that value to a hidden ~/.forge/.remote file. The gist is hosted under an anonymous GitHub account unrelated to the package publisher and is mutable — its contents can be swapped by the gist owner at any time to stage arbitrary command-and-control configuration on installer hosts. The 72-hour dormancy window suppresses the network activity in CI, install-time sandboxes, and short-lived analysis environments, and the destination field is literally named c2 and stored in a dotfile named .remote.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

9f6244035d2e65cd84c001ff936ebc019b7139c8e2afadfadfd2026c60208e4b

Detection & response playbook

Backdoor / remote access
  1. Find it

    Search your lockfiles and build artifacts for gas-diff-core (version 1.0.0).

  2. If you installed it — respond

    gas-diff-core establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

  3. Did it already run?

    If gas-diff-core was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. gas-diff-core on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-016869

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks gas-diff-core-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Explore

gas-diff-core (npm) malicious package — MAL-2026-13517 | O3 Security