What does the boxy-maker-extendable-minihost malware do?

On require(), index.js loads _bridge.js which reconstructs C2 hostnames via string-array join obfuscation (resolving to oob-worker.cf10[1-3]-*.workers.dev mirrors and sdk.dl.wel1.ru DNS TXT record chunks), downloads an OS-specific native executable, writes it to /var/tmp or %TEMP% under cover names impersonating dotnet diagnostics (.cache_ , dotnet_diag_ .exe), sets 0755 permissions, and spawns it detached via /bin/sh -c or cmd. A local cache stamp at /tmp/.analytics_state gates re-execution (TTL ~20804s). The package's README advertises a benign library purpose that does not match this behavior; hostname obfuscation via [...].join("") is deliberate evasion of static inspection. The

Which versions of boxy-maker-extendable-minihost are malicious?

The following npm versions of boxy-maker-extendable-minihost are flagged malicious: 35.7.5. Treat any of these as compromised.

How do I remediate boxy-maker-extendable-minihost if I installed it?

boxy-maker-extendable-minihost 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 boxy-maker-extendable-minihost — how do I know if it already compromised me?

If boxy-maker-extendable-minihost 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 boxy-maker-extendable-minihost part of a known attack campaign?

Yes — boxy-maker-extendable-minihost is associated with the IN-MAL-2026-015333 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 boxy-maker-extendable-minihost 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 boxy-maker-extendable-minihost (version 35.7.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging boxy-maker-extendable-minihost across your stack and pipelines.

Malicious package

boxy-maker-extendable-minihostnpm

boxy-maker-extendable-minihost is a confirmed malicious npm package (MAL-2026-13059) that opens a backdoor for remote access (malicious version 35.7.5). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in boxy-maker-extendable-minihost (npm)

MAL-2026-13059

Immediate action

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

npm uninstall boxy-maker-extendable-minihost

What this malware does

On require(), index.js loads bridge.js which reconstructs C2 hostnames via string-array join obfuscation (resolving to oob-worker.cf10[1-3]-*.workers.dev mirrors and sdk.dl.wel1.ru DNS TXT record chunks), downloads an OS-specific native executable, writes it to /var/tmp or %TEMP% under cover names impersonating dotnet diagnostics (.cache<hex>, dotnet_diag_<hex>.exe), sets 0755 permissions, and spawns it detached via /bin/sh -c or cmd. A local cache stamp at /tmp/.analytics_state gates re-execution (TTL ~20804s). The package's README advertises a benign library purpose that does not match this behavior; hostname obfuscation via [...].join("") is deliberate evasion of static inspection. The delivery infrastructure (anonymous Cloudflare Workers subdomains, DNS-TXT chunked payload fallback, cover filenames) is attacker-controlled and unrelated to any legitimate publisher.

Malicious versions

1 flagged

35.7.5

Indicators of compromise (SHA-256)

08404cdfbfce9c8e1f4d6b5c4597504b8d1ee580eabfaa960e5d928b4d5505a4

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 boxy-maker-extendable-minihost (version 35.7.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging boxy-maker-extendable-minihost across your stack and pipelines.
If you installed it — respond
boxy-maker-extendable-minihost 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 boxy-maker-extendable-minihost 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 boxy-maker-extendable-minihost 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. boxy-maker-extendable-minihost on npm has been identified as a malicious package (version 35.7.5 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015333

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks boxy-maker-extendable-minihost-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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