registry / Data exfiltration / @coopeuch/components

@coopeuch/components

Coordinated vulnerability disclosure proof of concept for a dependency confusion issue.

This report shows the evidence for @coopeuch/components@1.999.999. 1 of 3 known versions is blocked or flagged. The newest version, 0.0.1-security, is allowed. See all versions.

AI Security Review

scanned 11d ago · by lpm-firewall-ai

The lifecycle hook performs automatic host-data exfiltration to an external endpoint. The absence of credential theft does not make the collection and transmission of identifying host information benign.

Static reason

One or more suspicious static signals were detected.; source matched previously finalized malicious package; routed for review; source fingerprint signature matched known malicious package; routed for review

Trigger

Installing the package runs its postinstall hook.

Impact

The collector receives host and user identifying information from the installing environment.

Mechanism

The hook builds a report from host information and posts it to the collector over HTTPS.

Attack narrative

Package installation automatically runs a hook that gathers host identifiers and environment details, then posts them to an external collector. The code provides no user-controlled activation step for this transmission.

AI rationale

Evidence

package.jsonpostinstall.js

Network endpoints1

collector.oob.s4yhii.com

Decision evidence

public snapshot

AI called this Malicious at 98.0% confidence as Malware with low false-positive risk.

Evidence for block

package.json runs postinstall.js automatically during installation.
postinstall.js builds a report containing the host name, user name, home directory, install path, and other host details.
The hook sends the report by HTTPS POST to collector.oob.s4yhii.com.
The hook invokes the send path without a user action.

Evidence against

The inspected code does not show credential collection or shell execution.

Behavioral surface

Source

EnvironmentVarsFilesystemNetwork

Supply chainNo supply-chain packaging signals triggered.

Manifest

NoLicense

scanned 2 file(s), 7.62 KB of source

Source & flagged code

7 flagged

package.jsonView file

•scripts.postinstall = node ./postinstall.js

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

10"scripts": { "postinstall": "node ./postinstall.js" }, "files": [ "README.md", "DI

High

Suspicious Lifecycle Evidence

package.json runs postinstall.js automatically during installation.

package.jsonView on unpkg · L10

•scripts.postinstall = node ./postinstall.js

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

postinstall.jsView file

17const fs = require("fs"); L18: const dns = require("dns"); L19: const path = require("path"); ... L24: "npm_command", L25: "npm[redacted]", L26: "npm[redacted]", L27: "npm[redacted]", L28: "npm[redacted]", L29: "npm[redacted]", ... L47: try { L48: pkg = require("./package.json"); L49: } catch (e) {

High

Host Fingerprint Exfiltration

Source collects local host identity data and sends it to an external endpoint.

postinstall.jsView on unpkg · L17

•matchType = normalized_sha256 matchedPackage = @coopeuch/core@1.999.999 matchedPath = postinstall.js matchedIdentity = npm:QGNvb3BldWNoL2NvcmU:1.999.999 similarity = 1.000 summary = normalized source hash matched finalized malicious source

High

Known Malware Source Similarity

Source file is highly similar to a previously finalized malicious package; route for source-aware review.

postinstall.jsView on unpkg

•matchType = malicious_source_fingerprint_signature signature = 1242e05b01062ef0 signatureType = suspicious_hashes sourceLabel = final_verdict:malicious matchedPackage = @coopeuch/core@1.999.999 matchedPath = postinstall.js matchedIdentity = npm:QGNvb3BldWNoL2NvcmU:1.999.999 similarity = 1.000 shingleOverlap = 2 summary = package final verdict is malicious

High

Known Malware Source Fingerprint Signature

Source fingerprint signature matches a known malicious package signature; route for source-aware review.

postinstall.jsView on unpkg

129const cpus = os.cpus() || []; const report = { poc: "dependency-confusion-proof", round: 3, contact: "s4yhii___ (npm) - coordinated vulnerability disclosure", package: pkg.name, version: pkg.version, resolvedFrom: pkg._resolved || null,

High

Suspicious Lifecycle Evidence

postinstall.js builds a report containing the host name, user name, home directory, install path, and other host details.

postinstall.jsView on unpkg · L129

Source & flagged code

7 flagged · loading source

package.jsonView file

•scripts.postinstall = node ./postinstall.js

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

10"scripts": { "postinstall": "node ./postinstall.js" }, "files": [ "README.md", "DI

High

Suspicious Lifecycle Evidence

package.json runs postinstall.js automatically during installation.

package.jsonView on unpkg · L10

•scripts.postinstall = node ./postinstall.js

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

postinstall.jsView file

Findings

6 High3 Medium3 Low

HighInstall Time Lifecycle Scriptspackage.json

HighHost Fingerprint Exfiltrationpostinstall.js

HighKnown Malware Source Similaritypostinstall.js

HighKnown Malware Source Fingerprint Signaturepostinstall.js

HighSuspicious Lifecycle Evidencepackage.json

HighSuspicious Lifecycle Evidencepostinstall.js

MediumAmbiguous Install Lifecycle Scriptpackage.json

MediumNetwork

MediumEnvironment Vars

LowScripts Present

LowFilesystem

LowNo License

Affected versions and remediation

This report applies to @coopeuch/components@1.999.999.

The versions list below shows the verdict for each recorded version.

Avoid installing @coopeuch/components@1.999.999. Remove it from direct dependencies and check your lockfile for transitive copies.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.
If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.

Evidence last updated: 2026-10-12 19:30:04.558Z (UTC).

Source advisory published: 2026-10-11 14:00:55.000Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.

Versions

3 known versions

0.0.1-securitylatestUnknown—AllowUnder ReviewOct 12, 2026, 7:07 PM 0.0.0-stageClean—AllowPublishedOct 12, 2026, 7:05 PM 1.999.999shownMaliciousData ExfiltrationBlockPublishedOct 11, 2026, 2:09 AM

AI Security Review

Decision evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

Versions

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Source & flagged code

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