Which versions of @opezneppelin/contracts are malicious?

The following npm versions of @opezneppelin/contracts are flagged malicious: 5.0.2. Treat any of these as compromised.

How do I remediate @opezneppelin/contracts if I installed it?

@opezneppelin/contracts is a typosquat — you almost certainly intended a legitimately-named package. Remove @opezneppelin/contracts, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed @opezneppelin/contracts — how do I know if it already compromised me?

If @opezneppelin/contracts was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is @opezneppelin/contracts part of a known attack campaign?

Yes — @opezneppelin/contracts is associated with the IN-MAL-2026-017647 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 @opezneppelin/contracts across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @opezneppelin/contracts (version 5.0.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @opezneppelin/contracts across your stack and pipelines.

Malicious package

@opezneppelin/contractsnpm

@opezneppelin/contracts is a confirmed malicious npm package (MAL-2026-13940) that typosquats a legitimate package to trick installs (malicious version 5.0.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @opezneppelin/contracts (npm)

MAL-2026-13940

Immediate action

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

npm uninstall @opezneppelin/contracts

What this malware does

@opezneppelin/contracts is a typosquat of @openzeppelin/contracts. Its postinstall lifecycle script (scripts/postinstall.js) hex-escapes all module names, method names, and string constants (fs, https, child_process, powershell, -NoP,.exe) and stores the download URL as a base64 literal that decodes to https://files.catbox.moe/9bppy2.zip. On Windows installers, the script downloads that ZIP to %TEMP%, expands it via PowerShell Expand-Archive, recursively searches the extracted contents for the first.exe, and spawns it detached. The destination is an anonymous, mutable file-host (catbox.moe) unrelated to any OpenZeppelin infrastructure, and the fetched executable is opaque attacker-controlled content. The behavior fires automatically on npm install without any user action, resulting in arbitrary code execution on the installer's Windows host.

Malicious versions

1 flagged

5.0.2

Indicators of compromise (SHA-256)

abe04ec28ed56cb0a253131129df8078d425f8a0c579c439ced9c75b6977a6ab

Detection & response playbook

Typosquat

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @opezneppelin/contracts (version 5.0.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @opezneppelin/contracts across your stack and pipelines.
If you installed it — respond
@opezneppelin/contracts is a typosquat — you almost certainly intended a legitimately-named package. Remove @opezneppelin/contracts, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If @opezneppelin/contracts was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks @opezneppelin/contracts before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. @opezneppelin/contracts on npm has been identified as a malicious package (version 5.0.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-017647

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks @opezneppelin/contracts-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

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