Which versions of forge-gas-diff are malicious?

The following npm versions of forge-gas-diff are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate forge-gas-diff if I installed it?

forge-gas-diff 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.

I already installed forge-gas-diff — how do I know if it already compromised me?

If forge-gas-diff was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is forge-gas-diff part of a known attack campaign?

Yes — forge-gas-diff is associated with the IN-MAL-2026-016870 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find forge-gas-diff across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for forge-gas-diff (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging forge-gas-diff across your stack and pipelines.

Malicious package

forge-gas-diffnpm

forge-gas-diff is a confirmed malicious npm package (MAL-2026-13516) 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 forge-gas-diff (npm)

MAL-2026-13516

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall forge-gas-diff

What this malware does

index.js is advertised as a Foundry gas-report diff utility but on module load / CLI run schedules a setTimeout of 259,200,000 ms (3 days) that calls https.get against https://gist.githubusercontent.com/opensource-crypto/3946ef88aa057c9d10f1a7d80391d164/raw/default.json. The gist is hosted on a GitHub account (opensource-crypto) unrelated to the declared package publisher (danird9). If the fetched JSON contains a c2 field, the value is persisted to ~/.forge-gas-diff.remote for later use. A separate getInstallId() routine writes a per-host UUID to ~/.forge-gas-diff, providing a stable install fingerprint. None of this behavior — outbound network fetch, install-ID generation, remote-config persistence, or a field literally named c2 — has any relationship to the advertised gas-diff functionality and is not documented in the package. The gist is author-mutable, so the content delivered to installers can be changed at any time without republishing the package; the 3-day delay places the fetch well outside typical install-time sandboxing windows. The mechanism is the staging half of a remote-config-driven dropper: a hidden update channel keyed to attacker-editable content on a third-party host, with persistence to a well-known filesystem path on the installer's machine.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

4b1f6143f5a7c6106ab4ba0a21a6adaf9020e332835b1e528de6f36b64537734

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for forge-gas-diff (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging forge-gas-diff across your stack and pipelines.
If you installed it — respond
forge-gas-diff 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.
Did it already run?
If forge-gas-diff was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks forge-gas-diff before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. forge-gas-diff 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-2026-016870

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

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

Malware detection Runtime egress monitoring

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