The tinyparrot package version 0.4.1 includes a postinstall script (src/build.js) that reconstructs strings such as 'https', 'POST', and the destination host 'rnjkerbf.org/P' from integer-encoded arrays using base decoders in src/const.js and src/helpers.js. It dynamically requires a resolved module and sends an HTTPS POST request to the attacker-controlled URL. The response header 'm' from this request is passed directly to child_process.execSync, allowing arbitrary shell commands from the attacker to execute on the victim's machine during 'npm install'. Errors are caught and suppressed to avoid detection. The obfuscation of the URL, HTTP method, and module name via numeric decoders is intended to evade static analysis.

This vulnerability enables remote code execution on any system that installs tinyparrot version 0.4.1 via npm. The attacker can run arbitrary shell commands with the privileges of the user performing the installation, potentially leading to full system compromise, data theft, or further malware deployment. The malicious code executes silently during installation, increasing the risk of unnoticed compromise.

No official patch or remediation is currently available for tinyparrot version 0.4.1. Users should avoid installing this package version. Verify the integrity and source of npm packages before installation. Consider using package auditing tools to detect malicious code. Monitor vendor advisories for updates or fixes. Since this is not a cloud service, remediation depends on users avoiding or removing the affected package.