Which versions of cheesebox are malicious?

The following RubyGems versions of cheesebox are flagged malicious: 10.0.1. Treat any of these as compromised.

How do I remediate cheesebox if I installed it?

Remove cheesebox 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.

I already installed cheesebox — how do I know if it already compromised me?

If cheesebox 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 cheesebox part of a known attack campaign?

Yes — cheesebox is associated with the IN-MAL-2026-022648 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 cheesebox across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for cheesebox (version 10.0.1).

Malicious package

cheeseboxRubyGems

Advisory published Nov 12, 2026Updated Nov 12, 2026

cheesebox is a confirmed malicious RubyGems package (MAL-2026-19157) that executes malicious code on install (malicious version 10.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in cheesebox (RubyGems)

MAL-2026-19157

Immediate action

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

gem uninstall cheesebox

What this malware does

The gem declares mkrf_conf.rb as a native extension in its gemspec, causing it to execute automatically during gem install. On execution the script reads installer-side system files (/etc/passwd, /etc/hosts, /etc/resolv.conf) and collects host identifiers (hostname, username, home directory, current working directory), then opens a TLS TCPSocket to the hardcoded Burp Collaborator subdomain xwx31i3e80kbj4h1s7wnh8yklbrdf33s.oastify.com on port 443 and POSTs the collected data as JSON. The destination is an attacker-controlled out-of-band interaction host, not any infrastructure related to the gem's declared purpose, and the data read is unrelated to building a native extension (no mkmf probing, no compilation of shipped sources).

Malicious versions

1 flagged

10.0.1

Indicators of compromise (SHA-256)

5b03698e5384db9f041d0e2caa51db10abc0d0dcbfc1e5e77b795acc4d8cec76

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for cheesebox (version 10.0.1).
If you installed it — respond
Remove cheesebox 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 cheesebox 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. cheesebox on RubyGems has been identified as a malicious package (version 10.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-022648

References

rubygems.org

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks cheesebox-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.

Malware detection Runtime egress monitoring

Explore

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