fastercodePyPI
Advisory published Updated
fastercode is a confirmed malicious PyPI package (MAL-2026-6206) that steals credentials and exfiltrates sensitive data (malicious versions 0.1.0, 0.1.1, 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in fastercode (PyPI)
What this malware does
The package advertises itself as a Python performance helper ("Make your Python code run faster") and exposes a single public function run(). On Windows, calling run() fetches BackgroundSyncService.exe from https://raw.githubusercontent.com/manhhungdev0603/kl.py/refs/heads/main/BackgroundSyncService.exe, writes it to %PROGRAMDATA%\BackgroundSyncService\, and launches it via subprocess.Popen([local_filepath], shell=True) (fastercode/core.py:7-22). The source URL is a mutable branch reference on a personal GitHub account; the repo is named kl.py (suggestive of "keylogger.py"); the binary is unsigned, unpinned, and unrelated to the package's advertised purpose. All exceptions during download/execute are swallowed silently. Package metadata lists author="Anonymous" with no email or homepage, consistent with a throwaway publish account. Any developer who imports fastercode and calls its only public API on Windows runs an attacker-controlled executable persisted under PROGRAMDATA.
The package contains code to download and run a malicious executable. The executable contains a remote access trojan controlled via Telegram bot, with capabilities like a keylogger, screen recording, command execution. It also attempts to gain persistence via startup registry keys.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-06-fastercode
Reasons (based on the campaign):
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Downloads and executes a remote executable.
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peristence-autorun
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uses-telegram-bot
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keylogger
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rat
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spyware-like
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for fastercode (3 malicious versions).
If you installed it — respond
fastercode 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 fastercode 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
- Kamil Mańkowski (kam193) · reporter
Detect & block this
O3 blocks fastercode-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.