Which versions of fsbrowse are malicious?

The following npm versions of fsbrowse are flagged malicious: 0.2.28. Treat any of these as compromised.

How do I remediate fsbrowse if I installed it?

fsbrowse 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 fsbrowse — how do I know if it already compromised me?

If fsbrowse 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 fsbrowse part of a known attack campaign?

Yes — fsbrowse is associated with the GHSA-pvvh-h7rh-2c7g, IN-MAL-2026-017291 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 fsbrowse 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 fsbrowse (version 0.2.28). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging fsbrowse across your stack and pipelines.

Malicious package

fsbrowsenpm

fsbrowse is a confirmed malicious npm package (MAL-2026-13722) that opens a backdoor for remote access (malicious version 0.2.28). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in fsbrowse (npm)

MAL-2026-13722

Immediate action

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

npm uninstall fsbrowse

What this malware does

The package's main entry file (index.js) contains a legitimate Express file-server module followed by a unicode-escape-obfuscated IIFE appended after whitespace padding. When the module is loaded (via require('fsbrowse'), server.js, or the fsbrowse bin), the trailing code queries Ethereum RPC endpoints (eth.blockscout.com, 1rpc.io/eth, eth.drpc.org, ethereum-rpc.publicnode.com, eth-mainnet.public.blastapi.io) for the latest outgoing transaction of hardcoded address 0xa322E5f3D311D3080e6f0121063e9aDC2490Ef1a, decodes two IPv4 addresses from the transaction to field, then fetches XOR-encrypted payloads from those hosts over http://<ip>:443/0x/cls and executes the decrypted Node code via eval and via spawn('node', ['-e',...], { detached: true, stdio: 'ignore' }). Core module names (http, https, zlib, url, child_process), method names (spawn, eth_getBlockByNumber, eth_getTransactionCount), destination URLs, the Ethereum address, and XOR keys are all written as \u00XX escape sequences to hide the behavior from casual review. This is the EtherHiding technique: on-chain resolution of C2 IPs to defeat static blocklists, followed by fetch-and-execute of attacker-supplied code with the installer's privileges at import time.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Malicious versions

1 flagged

0.2.28

Indicators of compromise (SHA-256)

f9a611d53c7fd672a4e95a139a4eb18692d4a5a265c22c328e20a99b59ac432e

5b7866973ba5f2971efedd027cce57aefb5b8f27d7304de323261832c29bbd82

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 fsbrowse (version 0.2.28). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging fsbrowse across your stack and pipelines.
If you installed it — respond
fsbrowse 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 fsbrowse 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 fsbrowse 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. fsbrowse on npm has been identified as a malicious package (version 0.2.28 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-pvvh-h7rh-2c7gIN-MAL-2026-017291

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks fsbrowse-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

Explore

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