cleanup-stringPyPI
Advisory published Updated
cleanup-string is a confirmed malicious PyPI package (MAL-2026-17325) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in cleanup-string (PyPI)
What this malware does
The package advertises itself as a pure-Python string helper (strip, slugify, case conversion, whitespace collapse) and its README states the implementation is standard-library only. However, cleanup_string/__init__.py performs from._impl import cleanup, which loads a 1.3 MB Windows-only native extension cleanup_string/_impl.cp313-win_amd64.vmp.pyd (sha256 980ae204f04f9a7e68666670eb5b236bc7347d0111697df1015de665fd1a1712). The filename embeds the VMProtect convention .vmp and the binary matches that packer's signature: the only readable strings are Win32 API imports (LoadLibraryA, GetModuleHandleA, HeapAlloc, DisableThreadLibraryCalls, ExitProcess, KERNEL32.dll, VCRUNTIME140.dll) and the remaining ~1.3 MB is high-entropy virtualized code. VMProtect exists to defeat static and dynamic analysis; the trivial advertised functionality has no legitimate need for a virtualized native module. Any Windows Python 3.13 environment that imports cleanup_string executes this opaque, anti-analysis-protected code with the privileges of the importing process.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for cleanup-string (version 1.0.0).
If you installed it — respond
Remove cleanup-string from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If cleanup-string was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks cleanup-string-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.