This weekly list covers the ten most significant malicious or compromised packages recently observed in public registries.

1. yuinpm (npm)

Malicious package detected.

2. @apexfdn/apex (npm)

The install.cjs script follows a well-known legitimate pattern — downloading a platform-specific binary from GitHub releases on postinstall — consistent with tools like esbuild or puppeteer. The use of process.platform is purely for binary selection, not exfiltration; the IOC classifier mislabeled the download URL as 'exfil.' The 'chalk is malicious' dependency finding is almost certainly a false positive — chalk is one of the most widely used npm packages in the ecosystem. The primary residual risk is that the downloaded pre-built binaries (apex-linux-x64, apex-darwin-arm64, etc.) cannot be audited from this evidence alone, and the tool self-describes as a coding agent with bash execution capability backed by external services (hindsight.vectorize.io, omp.sh) whose behavior is opaque without examining apex.cjs more deeply.

3. upjsma (npm)

Malicious package detected.

4. rollup-plugin-polyfill-helper (npm)

Malicious package detected. Behaviors: data exfiltration, code execution.

5. chai-leaf (npm)

Malicious package detected. Behaviors: code execution, obfuscated code.

6. nolby (npm)

The package is a supply-chain attack targeting developers running WSL (Windows Subsystem for Linux). The _sync function at the bottom of index.mjs — deliberately separated from the legitimate calendar-math library code above it — detects a WSL environment via process.platform === 'linux' and the presence of /mnt/c, enumerates Windows user profiles by scanning for NTUSER.DAT, then copies a bundled file cache.dat from the package directory into the Windows Startup folder (AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup) renamed as vite-native-helper.exe. This is a textbook persistence dropper: cache.dat is the malicious payload, the startup folder write guarantees execution on every Windows login, and the disguise name (vite-native-helper.exe) borrows legitimacy from the Vite build tool. The NODE_ENV === 'production' guard ensures the payload only fires on developer machines. The surrounding library code is plausible enough to avoid immediate suspicion.

7. cors-update (npm)

Suspicious package detected.

8. chai-as-reddit (npm)

Malicious package detected. Behaviors: code execution, obfuscated code.

9. veskra (npm)

The package installs the malicious "nolby" package.

10. tailwindcss-form-components (npm)

Malicious package detected. Behaviors: code execution.

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Credits for the core data goes to https://opensourcemalware.com