boxy-test-block-fixturenpm
boxy-test-block-fixture is a confirmed malicious npm package (MAL-2026-13089) that executes malicious code on install (malicious version 35.5.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in boxy-test-block-fixture (npm)
What this malware does
On require()/import of the package, init.js assembles attacker-controlled hostnames at runtime by joining split string fragments (resolving to oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev), fetches a platform-specific binary over HTTPS, and if that fails, falls back to a DNS-TXT covert channel that reassembles base64-encoded payload chunks from subdomains of dl.wel1.ru. The downloaded bytes are written to /var/tmp or %TEMP% under cover-story names such as 'dotnet_diag.exe' and '.cache_', chmod 0755, and executed detached via cp.spawn('/bin/sh', ['-c', fp + ' &'], {detached:true}).unref() (or the cmd equivalent on Windows). No signature or hash verification is performed. The destination hostnames are obfuscated via array-join splitting to evade static string scans, and the DNS-TXT fallback bypasses HTTPS egress filtering. Any project that installs and loads this package executes attacker-controlled native code on the host.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for boxy-test-block-fixture (version 35.5.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging boxy-test-block-fixture across your stack and pipelines.
If you installed it — respond
Remove boxy-test-block-fixture from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If boxy-test-block-fixture 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-test-block-fixture 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks boxy-test-block-fixture-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.