Malicious Rust crates impersonate proc-macro2 to drop PowerShell backdoor

cyb3rops · x · 2026-08-20

Security researchers identified two malicious Rust crates—proc-macro1 v1.0.107 and proc-macro-en v1.0.10—that spoof the legitimate proc-macro2 ecosystem.

Attack Vector:

Both contain a malicious build.rs that downloads and executes a platform-specific payload during cargo build, cargo check, or cargo test.

Windows Payload Capabilities:

The payloads currently have a low detection rate on VirusTotal.

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