Which versions of xrblocks-mcp are malicious?

The following npm versions of xrblocks-mcp are flagged malicious: 6.3.1. Treat any of these as compromised.

How do I remediate xrblocks-mcp if I installed it?

xrblocks-mcp 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 xrblocks-mcp — how do I know if it already compromised me?

If xrblocks-mcp 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 xrblocks-mcp part of a known attack campaign?

Yes — xrblocks-mcp is associated with the IN-MAL-2026-017671 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 xrblocks-mcp across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for xrblocks-mcp (version 6.3.1).

Malicious package

xrblocks-mcpnpm

Advisory published Aug 13, 2026Updated Aug 13, 2026

xrblocks-mcp is a confirmed malicious npm package (MAL-2026-13988) that opens a backdoor for remote access (malicious version 6.3.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in xrblocks-mcp (npm)

MAL-2026-13988

Immediate action

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

npm uninstall xrblocks-mcp

What this malware does

The package's postinstall lifecycle script runs automatically on npm install and collects installer host identifiers (hostname, platform, arch, node version, package name, timestamp) and POSTs them to the hardcoded endpoint https://6cjhdzmo.instances.poc.jchunt.top/xrblocks-mcp. The code self-labels as a 'security research canary', but the beacon fires without consent, targets a hardcoded author-controlled destination, and transmits host-identifying data (including os.hostname()) that has no bearing on the package's declared functionality.

Malicious versions

1 flagged

6.3.1

Indicators of compromise (SHA-256)

76393473878ee61f371bcb238c278a7ae68f2a802d5a8b017d72812ab61c3c09

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for xrblocks-mcp (version 6.3.1).
If you installed it — respond
xrblocks-mcp 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 xrblocks-mcp 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. xrblocks-mcp on npm has been identified as a malicious package (version 6.3.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-017671

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks xrblocks-mcp-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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