registry / Data exfiltration / @s4yhiitestpoc/r2-https-b / 1.0.0

@s4yhiitestpoc/r2-https-b@1.0.0

Round-2 sample: postinstall sends a minimal install fingerprint plus npm's own registry configuration over HTTPS. No credentials or general environment variables are read.

AI Security Review

scanned 11d ago · by lpm-firewall-ai

The active install hook performs outbound collection and transmission of host and registry configuration metadata. This is concrete install-time data exfiltration, so publication should be blocked.

Static reason

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

Trigger

Installing the package runs its postinstall script.

Impact

The collector receives identifying build-environment information, including configured registry and local network details.

Mechanism

The script gathers machine identity, network details, and selected npm environment values, then sends them over HTTPS and performs a secondary DNS lookup.

Attack narrative

On installation, the postinstall script gathers host and user identity, network details, and selected npm configuration values. It transmits the report to an external HTTPS collector and makes a secondary DNS lookup, exposing build-environment information without an explicit user action beyond installation.

AI rationale

The active install hook performs outbound collection and transmission of host and registry configuration metadata. This is concrete install-time data exfiltration, so publication should be blocked.

Evidence

package.jsonpostinstall.js

Network endpoints2

collector.oob.s4yhii.comdb03o8lag74hsugsg2j091t8mfcf437h3.oob.s4yhii.com

Decision evidence

public snapshot

AI called this Malicious at 99.0% confidence as Malware with low false-positive risk.

Evidence for block

The postinstall hook runs automatically during installation.
The hook collects host, user, home-directory, network-interface, DNS, and npm registry/configuration metadata.
It sends the report by HTTPS POST to an external collector and also makes a DNS lookup to an external host.

Evidence against

The inspected code does not collect file contents, credentials, or general environment variables; its npm environment reads are limited to a fixed list.

Behavioral surface

Source

EnvironmentVarsNetwork

Supply chainNo supply-chain packaging signals triggered.

ManifestNo manifest risk signals triggered.

scanned 1 file(s), 3.62 KB of source

Source & flagged code

9 flagged

package.jsonView file

•scripts.postinstall = node ./postinstall.js

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

6"scripts": { "postinstall": "node ./postinstall.js" }, "files": ["RE

High

Suspicious Lifecycle Evidence

The postinstall hook runs automatically during installation.

package.jsonView on unpkg · L6

•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

Lines 1-40javascript

1// Dependency-confusion proof-of-concept beacon (round 2).

2//

3// Purpose: give the owner of an affected build environment verifiable evidence

4// that a package served by the PUBLIC npm registry executed inside their

5// pipeline, and that their own internal registry was configured at the time.

6//

7// NOT collected: credentials, API tokens, SSH keys, cloud instance metadata,

8// file contents, process arguments, command output, or environment variables

9// generally. The only environment variables read are the fixed npm_* allowlist

10// below, which npm itself sets for every lifecycle script and which contain

11// npm's own configuration -- never user secrets. No shell is spawned, no file

Lines 56-116javascript

56 for (const name of Object.keys(ifaces)) {

57 for (const addr of ifaces[name] || []) {

58 if (!addr.internal) out.push(name +

•matchType = malicious_source_fingerprint_signature signature = 3f96740e98080c96 signatureType = suspicious_hashes sourceLabel = final_verdict:malicious matchedPackage = @s4yhiitestpoc/r2-https@1.0.0 matchedPath = postinstall.js matchedIdentity = npm:QHM0eWhpaXRlc3Rwb2MvcjItaHR0cHM:1.0.0 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

Source & flagged code

9 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

6"scripts": { "postinstall": "node ./postinstall.js" }, "files": ["RE

High

Suspicious Lifecycle Evidence

The postinstall hook runs automatically during installation.

package.jsonView on unpkg · L6

•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

8 High3 Medium1 Low

HighInstall Time Lifecycle Scriptspackage.json

HighHost Fingerprint Exfiltrationpostinstall.js

HighKnown Malware Source Fingerprint Signaturepostinstall.js

HighSuspicious Lifecycle Evidencepackage.json

HighAi Review Evidencepostinstall.js

MediumAmbiguous Install Lifecycle Scriptpackage.json

MediumNetwork

MediumEnvironment Vars

LowScripts Present

Affected versions and remediation

This report applies to @s4yhiitestpoc/r2-https-b@1.0.0.

See all versions of @s4yhiitestpoc/r2-https-b for other recorded verdicts.

Avoid installing @s4yhiitestpoc/r2-https-b@1.0.0. 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 06:53:59.291Z (UTC).

Source advisory published: 2026-10-12 05:27:26.000Z (UTC).

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

AI Security Review

Decision evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

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Source & flagged code