What does the zsender malware do?

Campaign is split into multiple packages that altogether exfiltrates data from desktop Telegram application. 1. "pyapiepo" is a cover package that provides some useless features BUT also imports "zscaner" 2. "zscaner", when imported, automatically runs a function that is an entry point to the whole process; it uses the "scan" from "reqinstall" to walk through directories. The package also provides main logic: filtering files, triggering archiving directories and exfiltrating them. 3. "reqinstall" ensures "requests" are installed and provides a directory tree scanning function. 4. "zmaker" provides functions to build archives from collected files. 5. "zsender" provides functions to exfiltrat

Which versions of zsender are malicious?

The following PyPI versions of zsender are flagged malicious: 1.2.7. Treat any of these as compromised.

How do I remediate zsender if I installed it?

zsender 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.

I already installed zsender — how do I know if it already compromised me?

If zsender 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.

Is zsender part of a known attack campaign?

Yes — zsender is associated with the 2025-04-zscaner campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find zsender across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for zsender (version 1.2.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging zsender across your stack and pipelines.

Malicious package

zsenderPyPI

Malicious code in zsender (PyPI) Remove it immediately and rotate any exposed credentials.

MAL-2025-191945

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

pip uninstall zsender

What this malware does

Campaign is split into multiple packages that altogether exfiltrates data from desktop Telegram application.

"pyapiepo" is a cover package that provides some useless features BUT also imports "zscaner"
"zscaner", when imported, automatically runs a function that is an entry point to the whole process; it uses the "scan" from "reqinstall" to walk through directories. The package also provides main logic: filtering files, triggering archiving directories and exfiltrating them.
"reqinstall" ensures "requests" are installed and provides a directory tree scanning function.
"zmaker" provides functions to build archives from collected files.
"zsender" provides functions to exfiltrate data, the remote URL and a function to deobfuscate configuration in other packages.

Altogether, they look for "Telegram Desktop" folder, archive user data stored there and exfiltrate to a remote location.

Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2025-04-zscaner

Reasons (based on the campaign):

target:telegram
exfiltration-generic
The malicious code is intentionally included in a dependency of the package

Malicious versions

1 flagged

1.2.7

Indicators of compromise (SHA-256)

bbea3884909fc4de5c28947d3ddee545fc4922cc2881a678ed50536a7be365cf

64454f4348553cc0321094cffaef685d8977dd95ccf1c07dc54e2b8b3c39a8f0

d5772de1da404ef7501981ed6bffd40608f3942ba75abb398feab77aa6c350eb

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for zsender (version 1.2.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging zsender across your stack and pipelines.
If you installed it — respond
zsender 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 zsender 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 zsender 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

No. zsender on PyPI has been identified as a malicious package (version 1.2.7 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2025-04-zscaner

References

bad-packages.kam193.eu

Credits

Kamil Mańkowski (kam193)

Detect & block this

O3 blocks zsender-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring