Which versions of arb-kit are malicious?

The following npm versions of arb-kit are flagged malicious: 1.0.1. Treat any of these as compromised.

How do I remediate arb-kit if I installed it?

arb-kit is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

I already installed arb-kit — how do I know if it already compromised me?

If arb-kit 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 arb-kit part of a known attack campaign?

Yes — arb-kit is associated with the IN-MAL-2026-018377 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 arb-kit 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 arb-kit (version 1.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging arb-kit across your stack and pipelines.

Malicious package

arb-kitnpm

arb-kit is a confirmed malicious npm package (MAL-2026-14263) that steals credentials and exfiltrates sensitive data (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in arb-kit (npm)

MAL-2026-14263

Immediate action

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

npm uninstall arb-kit

What this malware does

arb-kit advertises itself as an Arbitrum ABI/gas toolkit, but the main entry (index.js) contains an IIFE that, 37 seconds after require, reads a base64 blob from test/fixtures/keypairs.dat, decodes it, and writes the decoded JavaScript to ~/.cache-db/.node-sync/syncd.js. It then installs OS-appropriate boot persistence (crontab on Linux, schtasks on Windows, a LaunchAgent plist labeled com.apple.syncd on macOS) and spawns node on the dropped script detached. The dropped payload walks the filesystem searching for files matching wallet, seed, mnemonic, private-key, keystore, and API-token keywords across extensions such as.env,.key,.keystore,.pem,.json, and.dat, specifically targeting Metamask, Phantom, Ledger, Trezor, Solana, Ethereum, and Bitcoin key material. Harvested files are RSA-encrypted with an embedded public key and uploaded to IPFS via api.pinata.cloud using a hardcoded Pinata API key and secret; runtime configuration is fetched from a hardcoded GitHub Gist raw URL under the user 'juang55'. The disguised staging path (.cache-db/.node-sync), the 'test fixture' cover for the second-stage payload, and the 'phantom syncd v3 — topo durmiente' internal comment confirm intentional concealment.

Malicious versions

1 flagged

1.0.1

Indicators of compromise (SHA-256)

ef3587f45144a9473e246cbffd1c4d03c2f895aa5052801282c4e1dd3e76be30

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for arb-kit (version 1.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging arb-kit across your stack and pipelines.
If you installed it — respond
arb-kit is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If arb-kit 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 arb-kit 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. arb-kit on npm has been identified as a malicious package (version 1.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-018377

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks arb-kit-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

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