jsonschema-viewerPyPI
Advisory published Updated
jsonschema-viewer is a confirmed malicious PyPI package (MAL-2026-6248) that steals credentials and exfiltrates sensitive data (malicious version 0.1.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in jsonschema-viewer (PyPI)
What this malware does
The package's only function — main() in src/jsonschema_viewer/main.py, registered as the jsonschema-viewer console script — invokes os.system to fetch a shell script from http://49.232.169.67:8084/slt via curl or wget and pipes the response into sh. The fetch uses plaintext HTTP to a bare IP with no pinning, no hash verification, and an opaque payload, and bears no relationship to the package's advertised purpose ('A minimal jsonschema-viewer package'). Author metadata is the placeholder 'Your Name' with no email/URL and the README is a single empty sentence, consistent with a throwaway dropper package. Any developer who installs this package and runs the documented CLI executes arbitrary attacker-controlled code on their machine.
Package configures an entry point (command line) that executes a remote script. It then downloads a next stage malware, which acts as next dropper for a fileless malware.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-06-jsonschema-viewer
Reasons (based on the campaign):
-
malware
-
Downloads and executes a remote executable.
-
Downloads and executes a remote malicious script.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for jsonschema-viewer (version 0.1.0).
If you installed it — respond
jsonschema-viewer 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 jsonschema-viewer 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 jsonschema-viewer-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.