{"answers":{"affected":"2 open source packages ship an affected version, including funcdesc.","exploited":"There is no known exploitation of MAL-2026-5300 in the wild and no public exploit code.","fix":"Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.","what":"MAL-2026-5300 is a malicious package in funcdesc, published on 6 Jun 2026."},"fix_prompt":"MAL-2026-5300 is a malicious package: funcdesc (PyPI). Every version was published to cause harm.\n\nTask:\n1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.\n2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.\n3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.\n4. If the package is not used anywhere, say so and change nothing.\n\nReference: https://insights.sbomify.com/MAL-2026-5300/ (Markdown: https://insights.sbomify.com/MAL-2026-5300/index.md)","id":"MAL-2026-5300","markdown":"https://insights.sbomify.com/MAL-2026-5300/index.md","name":"MAL-2026-5300","record":{"aliases":["PYSEC-2026-591"],"analysis":null,"analysis_generated_by":null,"assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"The package installs `funcdesc-setup.pth`, which Python auto-executes at interpreter startup for any environment where this package is installed. The.pth file is obfuscated with single-letter aliases (`_O`, `_T`, `_G`, `_o`, `_s`, `_u`,...) and wraps its real payload in `exec()` over an inline string, gated by a `/tmp/.bun_ran` sentinel. On first run it calls `urllib.request.urlretrieve` to download the Bun JavaScript runtime release archive from `https://github.com/oven-sh/bun/releases/download/bun-v1.3.13/bun-\u003cplatform\u003e-\u003carch\u003e.zip`, extracts it to `/tmp/b/bun`, chmods it executable, and then invokes `bun run _index.js` against a bundled `_index.js` shipped inside the package. The advertised purpose of funcdesc is a Python function-description protocol; there is no legitimate reason for it to fetch and run an alternate JavaScript runtime, stage binaries in `/tmp`, or execute opaque bundled JS outside the documented Python API. The pattern (auto-loaded.pth, obfuscated exec, alternate-runtime dropper, mismatched purpose, in-file `__version__` still reading `0.2.1`) is consistent with a hijacked release rather than legitimate maintainer behavior. The harm fires automatically every time a Python interpreter starts in any environment where this version is installed, not only at `pip install`, giving the attacker arbitrary code execution on the installer's machine.\n\nVersions 0.2.2, 0.2.3 were compromised.\n\nCompromised 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.\n\nIt seems to be related to the recent Mini Shai Hulud campaign.\n\n---\n\nCategory: MALICIOUS - The campaign has clearly malicious intent, like infostealers.\n\nCampaign: 2026-06-compr-woodpecker\n\nReasons (based on the campaign):\n\n - compromised-package\n\n - exfiltration-env-variables\n\n - exfiltration-cloud-tokens\n\n - exfiltration-credentials\n\n - abuses-pth\n\n - obfuscation\n\n - infostealer\n\n - The package contains code to detect if it is running in a sandbox environment.\n\n - exfiltration-crypto\n\n - files-exfiltration\n\n - destructive-actions","ecosystems":["PyPI"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":false,"headline":"Malicious code in funcdesc (PyPI)","id":"MAL-2026-5300","indexable":true,"kev":null,"kind":"malicious","links":{"ecosystem":"PyPI","product":null,"products":[],"type":null,"year":"2026"},"n_packages":2,"n_references":null,"packages":[{"ecosystem":"PyPI","fixed":[],"introduced":[],"last_affected":[],"package":"funcdesc","purl":"pkg:pypi/funcdesc","source":"MAL-2026-5300"},{"ecosystem":"PyPI","fixed":[],"introduced":[],"last_affected":[],"package":"funcdesc","purl":"pkg:pypi/funcdesc","source":"PYSEC-2026-591"}],"products":null,"published":"2026-06-06","related":[],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"OpenSSF Malicious Packages","prefix":"MAL"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":null,"url":"https://insights.sbomify.com/MAL-2026-5300/"}