Chrome Extension Scanner & Viewer

View source code or scan extensions for malware

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Example Extensions

Easy TikTok Video Downloader

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\n View Source\n Scan\n

uBlock Origin

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\n View Source\n Scan\n

React Developer Tools

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\n View Source\n Scan\n

JSON Viewer

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\n View Source\n Scan\n

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API Routes

\n /view/URL\n View extension source code in StackBlitz\n

\n /scan/URL\n Upload to VirusTotal and redirect to analysis\n

\n /api/crx/:id\n Download CRX file (CORS proxy)\n

\n\n \n\n`;\n\n return new Response(html, {\n headers: { \"Content-Type\": \"text/html; charset=utf-8\" },\n });\n}\n\nasync function handleCrxProxy(extensionId: string): Promise {\n // Validate extension ID format\n if (!/^[a-z]{32}$/.test(extensionId)) {\n return new Response(\n JSON.stringify({ error: \"Invalid extension ID format\" }),\n { status: 400, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n console.log(`[vtotal] Proxying CRX for extension: ${extensionId}`);\n\n const crxUrl = buildCrxDownloadUrl(extensionId);\n\n try {\n const response = await fetch(crxUrl, {\n headers: {\n \"User-Agent\": \"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36\",\n Referer: \"https://chrome.google.com/webstore\",\n },\n });\n\n if (!response.ok) {\n throw new Error(`CRX download failed: ${response.status}`);\n }\n\n const crxData = await response.arrayBuffer();\n console.log(`[vtotal] Proxied CRX: ${crxData.byteLength} bytes`);\n\n return new Response(crxData, {\n headers: {\n \"Content-Type\": \"application/x-chrome-extension\",\n \"Content-Length\": crxData.byteLength.toString(),\n \"Access-Control-Allow-Origin\": \"*\",\n \"Cross-Origin-Resource-Policy\": \"cross-origin\",\n },\n });\n } catch (error) {\n console.error(`[vtotal] CRX proxy error:`, error);\n return new Response(\n JSON.stringify({\n error: \"CRX download failed\",\n message: error instanceof Error ? error.message : \"Unknown error\",\n }),\n { status: 502, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n}\n\nfunction stripCrxHeader(buffer: ArrayBuffer): ArrayBuffer {\n const view = new DataView(buffer);\n if (buffer.byteLength < 12) return buffer;\n\n const magic = view.getUint32(0, true);\n if (magic !== 0x34327243) return buffer; // \"Cr24\" magic number\n\n const version = view.getUint32(4, true);\n let zipStart: number;\n\n if (version === 2) {\n const keyLen = view.getUint32(8, true);\n const sigLen = view.getUint32(12, true);\n zipStart = 16 + keyLen + sigLen;\n } else if (version === 3) {\n const headerLen = view.getUint32(8, true);\n zipStart = 12 + headerLen;\n } else {\n return buffer;\n }\n\n return buffer.slice(zipStart);\n}\n\nfunction isTextFile(filename: string): boolean {\n const textExtensions = [\n \"js\", \"mjs\", \"jsx\", \"ts\", \"tsx\", \"json\", \"html\", \"htm\", \"css\", \"scss\",\n \"less\", \"xml\", \"svg\", \"md\", \"txt\", \"yaml\", \"yml\", \"sh\", \"bash\", \"py\",\n \"rb\", \"php\", \"java\", \"c\", \"cpp\", \"h\", \"hpp\", \"rs\", \"go\", \"swift\",\n ];\n const ext = filename.split(\".\").pop()?.toLowerCase() || \"\";\n return textExtensions.includes(ext);\n}\n\nasync function extractExtensionFiles(extensionId: string): Promise> {\n const crxUrl = buildCrxDownloadUrl(extensionId);\n const response = await fetch(crxUrl, {\n headers: {\n \"User-Agent\": \"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36\",\n Referer: \"https://chrome.google.com/webstore\",\n },\n });\n\n if (!response.ok) {\n throw new Error(`CRX download failed: ${response.status}`);\n }\n\n const crxBuffer = await response.arrayBuffer();\n const zipBuffer = stripCrxHeader(crxBuffer);\n\n // Use fflate for server-side zip extraction\n // @ts-ignore: dynamic import from esm.sh\n const fflate = await import(\"https://esm.sh/fflate@0.8.2\");\n const zipData = new Uint8Array(zipBuffer);\n const unzipped = fflate.unzipSync(zipData) as Record;\n\n const files: Record = {};\n const decoder = new TextDecoder();\n\n for (const [path, data] of Object.entries(unzipped)) {\n if (isTextFile(path)) {\n try {\n files[path] = decoder.decode(data);\n } catch {\n // Skip files that can't be decoded as text\n }\n }\n }\n\n return files;\n}\n\nfunction generateStackBlitzFormHtml(extensionId: string, files: Record): string {\n // StackBlitz accepts POST to /run with form data\n // project[title], project[template], project[files][path]=content\n const inputs: string[] = [];\n\n inputs.push(``);\n inputs.push(``);\n\n for (const [path, content] of Object.entries(files)) {\n const escapedContent = content\n .replace(/&/g, \"&\")\n .replace(/\"/g, \""\")\n .replace(//g, \">\");\n inputs.push(``);\n }\n\n return `\n\n\n Opening in StackBlitz...\n \n\n\n

Opening extension in StackBlitz...

\n \n \n\n`;\n}\n\nasync function handleView(chromeStoreUrl: string): Promise {\n let extensionId: string;\n try {\n extensionId = extractExtensionId(chromeStoreUrl);\n } catch (error) {\n return new Response(\n JSON.stringify({\n error: \"Invalid URL\",\n message: error instanceof Error ? error.message : \"Could not parse extension ID\",\n }),\n { status: 400, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n console.log(`[vtotal] Extracting extension server-side: ${extensionId}`);\n\n try {\n const files = await extractExtensionFiles(extensionId);\n console.log(`[vtotal] Extracted ${Object.keys(files).length} files`);\n\n const html = generateStackBlitzFormHtml(extensionId, files);\n\n return new Response(html, {\n headers: { \"Content-Type\": \"text/html; charset=utf-8\" },\n });\n } catch (error) {\n console.error(`[vtotal] Extraction error:`, error);\n return new Response(\n JSON.stringify({\n error: \"Extension extraction failed\",\n message: error instanceof Error ? error.message : \"Unknown error\",\n extensionId,\n }),\n { status: 502, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n}\n\nasync function handleScan(chromeStoreUrl: string): Promise {\n // Validate input\n if (!chromeStoreUrl || !chromeStoreUrl.includes(\"chromewebstore.google.com\")) {\n return new Response(\n JSON.stringify({ error: \"Invalid URL\", message: \"Provide a valid Chrome Web Store URL\" }),\n { status: 400, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n // Extract extension ID\n let extensionId: string;\n try {\n extensionId = extractExtensionId(chromeStoreUrl);\n } catch (error) {\n return new Response(\n JSON.stringify({\n error: \"Invalid URL\",\n message: error instanceof Error ? error.message : \"Could not parse extension ID\",\n }),\n { status: 400, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n console.log(`[vtotal] Processing extension: ${extensionId}`);\n\n // Download CRX from Google's update service\n const crxUrl = buildCrxDownloadUrl(extensionId);\n console.log(`[vtotal] Downloading CRX from: ${crxUrl}`);\n\n let crxBlob: Blob;\n try {\n const crxResponse = await fetch(crxUrl, {\n headers: {\n \"User-Agent\": \"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36\",\n Referer: \"https://chrome.google.com/webstore\",\n },\n });\n\n if (!crxResponse.ok) {\n throw new Error(`CRX download failed: ${crxResponse.status} ${crxResponse.statusText}`);\n }\n\n crxBlob = await crxResponse.blob();\n console.log(`[vtotal] Downloaded CRX: ${crxBlob.size} bytes`);\n } catch (error) {\n return new Response(\n JSON.stringify({\n error: \"CRX download failed\",\n message: error instanceof Error ? error.message : \"Unknown error\",\n extensionId,\n }),\n { status: 502, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n // Upload to VirusTotal API v3\n const vtApiKey = Deno.env.get(\"VIRUSTOTAL_API_KEY\");\n if (!vtApiKey) {\n return new Response(\n JSON.stringify({\n error: \"Configuration error\",\n message: \"VIRUSTOTAL_API_KEY environment variable not set\",\n }),\n { status: 500, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n console.log(`[vtotal] Uploading to VirusTotal...`);\n\n let vtResult: { data?: { id?: string }; error?: { message?: string } };\n try {\n const formData = new FormData();\n formData.append(\"file\", crxBlob, `${extensionId}.crx`);\n\n const vtResponse = await fetch(\"https://www.virustotal.com/api/v3/files\", {\n method: \"POST\",\n headers: { \"x-apikey\": vtApiKey },\n body: formData,\n });\n\n vtResult = await vtResponse.json();\n\n if (!vtResponse.ok) {\n throw new Error(vtResult.error?.message || `VirusTotal API error: ${vtResponse.status}`);\n }\n\n console.log(`[vtotal] VirusTotal response:`, JSON.stringify(vtResult));\n } catch (error) {\n return new Response(\n JSON.stringify({\n error: \"VirusTotal upload failed\",\n message: error instanceof Error ? error.message : \"Unknown error\",\n extensionId,\n }),\n { status: 502, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n // Extract analysis ID and redirect to VirusTotal\n const analysisId = vtResult.data?.id;\n if (!analysisId) {\n return new Response(\n JSON.stringify({\n error: \"VirusTotal response error\",\n message: \"No analysis ID in response\",\n vtResult,\n }),\n { status: 502, headers: { \"Content-Type\": \"application/json\" } },\n );\n }\n\n const redirectUrl = `https://www.virustotal.com/gui/file-analysis/${analysisId}`;\n console.log(`[vtotal] Redirecting to: ${redirectUrl}`);\n\n return Response.redirect(redirectUrl, 302);\n}\n\nexport default async function handler(req: Request): Promise {\n const url = new URL(req.url);\n const path = url.pathname.slice(1); // Remove leading /\n\n if (path.startsWith(\"api/crx/\")) {\n return handleCrxProxy(path.slice(8));\n } else if (path.startsWith(\"scan/\")) {\n return handleScan(path.slice(5));\n } else if (path.startsWith(\"view/\")) {\n return handleView(path.slice(5));\n } else {\n return showIndex();\n }\n}","deleted","label",[100],"permalink","https://www.val.town/x/spookyuser/crxtotal/code/main.ts","extension","actionData","errors"]