Which versions of csc-csc-core are malicious?

The following npm versions of csc-csc-core are flagged malicious: 35.8.6. Treat any of these as compromised.

How do I remediate csc-csc-core if I installed it?

csc-csc-core 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 csc-csc-core — how do I know if it already compromised me?

If csc-csc-core 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 csc-csc-core part of a known attack campaign?

Yes — csc-csc-core is associated with the IN-MAL-2026-015115 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 csc-csc-core across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for csc-csc-core (version 35.8.6).

Malicious package

csc-csc-corenpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

csc-csc-core is a confirmed malicious npm package (MAL-2026-12667) that opens a backdoor for remote access (malicious version 35.8.6). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in csc-csc-core (npm)

MAL-2026-12667

Immediate action

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

npm uninstall csc-csc-core

What this malware does

On require of csc-csc-core, index.js loads init.js which downloads a platform-specific binary from string-split obfuscated Cloudflare Workers hostnames (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev) with a DNS TXT chunked fallback via *.dl.wel1.ru subdomains, writes it to /var/tmp or %TEMP% under a disguised name (e.g..cache<hex>, dotnet_diag_<hex>.exe), chmods 0755, and spawns it detached via cp.spawn('/bin/sh',['-c', fp+' &'],{detached:true}).unref(). C2 hostnames and resolver domains are assembled at runtime from arrays of fragments to defeat static scanners. A /tmp cooldown marker and DO_NOT_TRACK opt-out are used to evade sandboxes. The README advertises the package as a 'base framework module' with no such behavior.

Malicious versions

1 flagged

35.8.6

Indicators of compromise (SHA-256)

0339e6587ac1d675e493fc3edc1e7d325982284f794a681327053e1131ce689c

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for csc-csc-core (version 35.8.6).
If you installed it — respond
csc-csc-core 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 csc-csc-core 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. csc-csc-core on npm has been identified as a malicious package (version 35.8.6 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015115

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks csc-csc-core-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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