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 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.

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?

Search your lockfiles and build artifacts for boxy-maker-extendable-minihost (version 35.7.5).

Malicious package

boxy-maker-extendable-minihostnpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

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
Search your lockfiles and build artifacts for boxy-maker-extendable-minihost (version 35.7.5).
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 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. 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

All malware advisories How O3 detects malware Vulnerability database