The npm package simple-date-formatter-new-12 version 1.0.0 includes a postinstall lifecycle script that runs automatically on npm install. This script uses curl to request an internal Baidu URL, writes the response to a temporary file, and then sends the file contents to an attacker-controlled interactsh collector domain. The package's advertised functionality is a trivial date-formatting wrapper, but the embedded SSRF probe and outbound data exfiltration are unrelated to its purpose. The package's naming pattern, lack of author metadata, and exfiltration behavior suggest it is a malicious dependency confusion or typosquatting probe designed to detect installation within target organizations and leak internal network responses.

Installation of this package results in execution of malicious code that performs server-side request forgery (SSRF) to an internal Baidu host and exfiltrates the response data to an attacker-controlled server. This can lead to leakage of internal network information and potentially sensitive data accessible from the installer's network environment. The malicious behavior is hidden in a package that appears to provide benign date formatting functionality, increasing the risk of inadvertent installation in development or production environments.

No official patch or remediation is indicated in the provided data. Users should avoid installing the simple-date-formatter-new-12 package version 1.0.0. Review and remove this package if already installed. Employ strict package source verification and dependency auditing to prevent installation of typosquatting or malicious packages. Monitor package registries and advisories for updates or removals related to this package.