proxy-check-ii

Details

**Severity:** Critical

**Affected versions:** `= 0.1.0`

## Source: amazon-inspector (a736498f3f882a4ba79f793dc893883db41d8cb5a74ecfe0c66dace9cc477a20)
The wheel is advertised as 'proxy-check-ii' with a one-line summary of 'packaged command for running the bundled qsshd executable' and no README, homepage, source, or author metadata. It installs a 7.7MB prebuilt Go binary at qsshd/bin/qsshd (sha256 b63ca13bc013aea83a8a9876ce1959cc07ced44e4912908e8d831f8c3b0fd72f) and a Python console script proxy-check-ii whose main() is a bare os.execv of that binary with any caller-supplied args forwarded. Strings in the binary show it links golang.org/x/crypto/ssh, github.com/hashicorp/yamux, and github.com/mydearniko/overthing/pkg/{relay,network,protocol} — an SSH/PTY server multiplexed over a yamux relay, consistent with a reverse-tunneled remote-shell overlay. The declared package name and metadata do not disclose that installing and running proxy-check-ii stands up an SSH daemon; the pure-python wheel tag also misrepresents the shipped platform-specific ELF payload. The Python wrapper performs no auditing or configuration of the binary — its runtime behavior (bind address, rendezvous endpoint, authorized keys, whether it dials out to a preset overlay) is opaque to the caller.

## Source: kam193 (8a222abeb680e48d3cffbdeb7f0d6cba713b023d825b2c42c7a849b36b2fe0a5)
The embedded binary starts a relayed SSH-like server using a hardcoded authorized_key. Thanks to using a relay network, the attacked does not need to directly expose ports from the machine.


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


Campaign: 2026-07-proxy-check-i


Reasons (based on the campaign):


 - backdoor


 - The package contains code to execute remote commands (probably limited to a specific set) on the victim's machine.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/proxy-check-ii/MAL-2026-10610.json))

**References:**
- https://bad-packages.kam193.eu/pypi/package/proxy-check-ii
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/proxy-check-ii/MAL-2026-10610.json
- https://pypi.org/project/proxy-check-ii/0.1.0
- https://github.com/advisories/GHSA-9cwf-f73q-pqg9

Compromised versions (1)

• = 0.1.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.