MalwarePublished 10 Jul 2026

@jaymara/jsononifier (npm) · Malicious Code

Affects @jaymara/jsononifierSource GCVE Database

Malicious package : remove @jaymara/jsononifier and rotate any secrets on hosts that installed it.

Data as of 13 Jul 2026, 09:19 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-10177

What to do

Remove @jaymara/jsononifier from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npm@jaymara/jsononifier	Affected =1.0.0 =1.0.2 =1.0.1	Fixed in–

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Description

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (ade6fb9a07c6f1417e9569af48b6c638bf12fba7540493b1b38a2d6ba42d101c) @jaymara/jsononifier@1.0.2 is advertised as a JSON formatting utility but ships a covert command-execution primitive that fires on require. index.js loads trigger.js, which checks for sandbox indicators (process.env.CI==='true', NODE_ENV==='test', existence of /.dockerenv) and the platform (win32); when those checks indicate a real Windows workstation, it schedules Executer.js via process.nextTick + setTimeout(5000). Executer.js XOR-decodes a byte array from payload.js using key 'xorkey123' and passes the resulting string to child_process.exec with { windowsHide: true }. payload.js openly comments the intent ('XOR-encoded command – not visible in source'). The current decoded value is a demo (calc.exe), but the mechanism — opaque encoded bytes decoded at runtime and handed to exec, gated to skip CI/test/Docker and only fire on real victim machines — is the attack: a future tarball can swap the byte array for any command without changing the visible code. None of this is required by, or consistent with, a JSON formatter.

Impact

The malicious code allows arbitrary command execution on Windows systems that import this package, potentially enabling attackers to run any commands with the privileges of the importing process. Although the current payload is benign (launching calc.exe), the mechanism can be modified to execute harmful commands, leading to system compromise, data theft, or further malware deployment. The code avoids execution in sandboxed or CI environments, increasing the risk of undetected exploitation on real victim machines.

Defensive guidance

Users should immediately remove and avoid using @jaymara/jsononifier versions 1.0.0, 1.0.1, and 1.0.2. Audit dependencies for this package and replace it with a trusted alternative. Monitor for any unexpected child process executions on Windows systems that import this package.

Summary

@jaymara/jsononifier versions 1.0.0, 1.0.1, and 1.0.2 include a hidden command execution backdoor triggered upon requiring the package. The index.js loads trigger.js, which checks environment variables and platform to avoid execution in CI, test, or Docker environments, and only activates on Windows workstations. It schedules Executer.js to decode an XOR-encoded command from payload.js and executes it with Windows process hiding enabled. The current payload launches calc.exe as a demonstration, but the encoded payload can be replaced to run arbitrary commands. This behavior is unrelated to the package's advertised JSON formatting functionality, indicating malicious intent.

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Jul 2026, 09:46 UTC

Technical details

References

Community reviews