instructor-mcpPyPI
Malicious code in instructor-mcp (PyPI) Remove it immediately and rotate any exposed credentials.
What this malware does
instructor-mcp 1.15.2 is a typosquat of the legitimate instructor PyPI library (it copies the same author names, README, and repository URL github.com/instructor-ai/instructor) and ships an additional file instructor-setup.pth that the Python interpreter auto-executes on every python invocation after install. The.pth file uses an obfuscated single-line exec(...) with mangled aliases (_o,_s,_u,_p,_y,_h,_g) to bypass the .pth rule that only import lines execute. The exec body downloads the Bun JavaScript runtime from https://github.com/oven-sh/bun/releases/download/bun-v1.3.13/bun-{platform}-{arch}.zip to /tmp/b/bun, chmods it executable, then searches sys.path for a file named _index.js and runs it via bun run _index.js. Execution is gated by /tmp/.bun_ran so it fires once per host. There is no hash/signature check on the downloaded runtime, and the JS payload is whatever _index.js happens to be present on sys.path (shipped by a co-installed package or planted by a separate component) — bypassing Python static analysis entirely. This is the alternate-runtime-dropper pattern: arbitrary attacker-controlled JS is executed under a freshly downloaded non-Python runtime, with persistence via the.pth auto-load mechanism.
Versions 1.15.2, 1.15.3 were compromised.
Compromised packages start an obfuscated infostealer. The infostealer is a heavily obfuscated JavaScript code executed using Bun runtime on Python startup. It collectes all kinds of sensitive data, including API keys, credentials to package repositories, cryptocurrency assets, password manager data. Infostealer actively queries online services to collect additional secrets as well as attempts to gain persistence and spread further by publishing infected packages using collected credentials. Data are exfiltrated likely using Github. The code seems to threaten to wipe the user's data if it detects invalid GitHub tokens. Cleanup should be done with caution.
It seems to be related to the recent Mini Shai Hulud campaign.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-06-compr-woodpecker
Reasons (based on the campaign):
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compromised-package
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exfiltration-env-variables
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exfiltration-cloud-tokens
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exfiltration-credentials
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abuses-pth
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obfuscation
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infostealer
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The package contains code to detect if it is running in a sandbox environment.
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exfiltration-crypto
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files-exfiltration
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destructive-actions
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for instructor-mcp (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging instructor-mcp across your stack and pipelines.
If you installed it — respond
instructor-mcp is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If instructor-mcp 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 instructor-mcp 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
Campaign
References
Credits
- Amazon Inspector · finder
- Kamil Mańkowski (kam193) · analyst
Detect & block this
O3 blocks instructor-mcp-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.