Which versions of proc-macro-en are malicious?

Every published version of proc-macro-en on crates.io is considered malicious. Remove the package entirely.

How do I remediate proc-macro-en if I installed it?

proc-macro-en 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 proc-macro-en — how do I know if it already compromised me?

If proc-macro-en 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.

How do I find proc-macro-en across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for proc-macro-en (all published versions).

Malicious package

proc-macro-encrates.io

Advisory published Aug 20, 2026Updated Aug 20, 2026

proc-macro-en is a confirmed malicious crates.io package (MAL-2026-14339) that opens a backdoor for remote access. Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in proc_macro_en (crates.io)

MAL-2026-14339

Immediate action

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

remove proc-macro-en

What this malware does

proc-macro-en is a malicious crate published to crates.io as part of the coordinated build-time payload campaign on 2026-08-20 that trojanized arrayref, internment, and append-only-vec and published the proc-macro1 typosquat of proc-macro2. It was used as an attacker-controlled dependency carrying a build-script payload; building it results in the download and execution of a remote binary from https://23.254.165.112:9089/ with 23.254.165.112:443 as command and control. All versions have been removed from crates.io. The individual build script of this crate was not analyzed directly; its behavior is attributed from the campaign.

Malicious versions

all versions

Every published version of this package is considered malicious — remove it entirely.

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for proc-macro-en (all published versions).
If you installed it — respond
proc-macro-en 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 proc-macro-en 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. proc-macro-en on crates.io has been identified as a malicious package (all published versions flagged). It should be removed immediately — do not install or keep it in your dependency tree.

References

Credits

SafeDep · finder
jhobern · reporter

Detect & block this

O3 blocks proc-macro-en-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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