Havaliman\u0131nda bekliyorsunuz, kafede \u00e7al\u0131\u015f\u0131yorsunuz ya da otelde bir toplant\u0131ya ba\u011flanmak istiyorsunuz. Telefon veya bilgisayar\u0131n Wi-Fi listesi a\u00e7\u0131l\u0131yor: onlarca a\u011f g\u00f6r\u00fcn\u00fcyor. “AirportFreeWifi”, “Starbucks_Guest”, “Hotel_Lobby” \u2014 birine dokunuyorsunuz, internet a\u00e7\u0131l\u0131yor, hayat devam ediyor. Ama arka planda, tamamen fark\u0131nda olmadan, verileriniz son derece savunmas\u0131z bir ortama girmi\u015f olabilir.<\/p>\n\n\n\n
Halka a\u00e7\u0131k Wi-Fi a\u011flar\u0131, siber g\u00fcvenlik d\u00fcnyas\u0131n\u0131n en kadim ve en etkili sald\u0131r\u0131 y\u00fczeylerinden biri. Bu yaz\u0131da, bu a\u011flar\u0131n tam olarak hangi riskleri bar\u0131nd\u0131rd\u0131\u011f\u0131n\u0131, bir sald\u0131rgan\u0131n bu ortamda ne yapabildi\u011fini ve kendinizi korumak i\u00e7in ne yapman\u0131z gerekti\u011fini konu\u015faca\u011f\u0131z.<\/p>\n\n\n\n
Ev veya i\u015f a\u011f\u0131n\u0131z b\u00fcy\u00fck olas\u0131l\u0131kla WPA2 veya WPA3 ile \u015fifrelenmi\u015f. Bu, o a\u011fa ba\u011fl\u0131 cihazlar aras\u0131ndaki trafi\u011fin \u015fifreli oldu\u011fu anlam\u0131na geliyor \u2014 a\u011f \u015fifresini bilseydiniz bile ba\u015fkas\u0131n\u0131n trafi\u011fini okuyamazs\u0131n\u0131z.<\/p>\n\n\n\n
Halka a\u00e7\u0131k a\u011flarda ise tablo farkl\u0131. \u00c7o\u011fu \u00fccretsiz Wi-Fi noktas\u0131 ya hi\u00e7 \u015fifresiz ya da herkese da\u011f\u0131t\u0131lan tek bir ortak \u015fifreyle korunan a\u011flar. Ortak \u015fifre durumunda, ayn\u0131 \u015fifreyi bilen herkes teorik olarak ayn\u0131 a\u011fdaki di\u011fer cihazlar\u0131n trafi\u011fini g\u00f6rebilir. Bu, phishing yaz\u0131m\u0131zda<\/a> anlatt\u0131\u011f\u0131m\u0131z sahte site tuzaklar\u0131ndan \u00e7ok farkl\u0131 ama ayn\u0131 \u00f6l\u00e7\u00fcde tehlikeli bir sald\u0131r\u0131 vekt\u00f6r\u00fc.<\/p>\n\n\n\n Halka a\u00e7\u0131k Wi-Fi’nin en klasik sald\u0131r\u0131 y\u00f6ntemi “ortadaki adam” (Man-in-the-Middle, MitM) sald\u0131r\u0131s\u0131. Ad\u0131 dramatik geliyor ama teknik olarak o kadar da zor de\u011fil.<\/p>\n\n\n\n Senaryo \u015f\u00f6yle: Bir kafe Wi-Fi’sine ba\u011fland\u0131n\u0131z. A\u011fda sizi dinleyen biri de var. Bu ki\u015fi, a\u011f trafi\u011fini izleyerek hangi sitelere ba\u011fland\u0131\u011f\u0131n\u0131z\u0131, hangi verileri g\u00f6nderdi\u011finizi ve baz\u0131 durumlarda ne yazd\u0131\u011f\u0131n\u0131z\u0131 g\u00f6rebilir. \u00d6zellikle HTTP (HTTPS de\u011fil) \u00fczerinden a\u00e7\u0131lan sayfalarda bu bilgi a\u00e7\u0131k metin olarak akar.<\/p>\n\n\n\n “Ama art\u0131k her yer HTTPS kullan\u0131yor” diyebilirsiniz \u2014 ve b\u00fcy\u00fck \u00f6l\u00e7\u00fcde hakl\u0131s\u0131n\u0131z. Ancak \u015funlar\u0131 g\u00f6z \u00f6n\u00fcnde bulundurun:<\/p>\n\n\n\n Bu konuda sosyal m\u00fchendislik yaz\u0131m\u0131zda<\/a> anlatt\u0131\u011f\u0131m\u0131za benzer bir dinamik var: Sald\u0131rgan teknik zay\u0131fl\u0131ktan de\u011fil, sizin dikkat a\u00e7\u0131\u011f\u0131n\u0131zdan yararlan\u0131yor. HTTPS kilidi var m\u0131 diye bakmadan ba\u011flant\u0131ya g\u00fcvenmek, i\u015fte o a\u00e7\u0131k.<\/p>\n\n\n\n MitM’den de tehlikeli olan senaryo \u015fu: Ba\u011fland\u0131\u011f\u0131n\u0131z a\u011f ger\u00e7ek kafe veya havaliman\u0131 a\u011f\u0131 bile olmayabilir.<\/p>\n\n\n\n “K\u00f6t\u00fc ikiz” (Evil Twin) sald\u0131r\u0131s\u0131nda, bir sald\u0131rgan ger\u00e7ek a\u011fla ayn\u0131 ya da \u00e7ok benzer bir isimde sahte bir Wi-Fi noktas\u0131 olu\u015fturur. “AirportWifi” ile “Airport_Wifi” aras\u0131ndaki fark h\u0131zla g\u00f6zden ka\u00e7ar. Cihaz\u0131n\u0131z daha \u00f6nce ba\u011fland\u0131\u011f\u0131 bu a\u011f\u0131 otomatik tan\u0131yabilir ve hi\u00e7 sormadan ba\u011flanabilir. Art\u0131k t\u00fcm trafi\u011finiz sald\u0131rgan\u0131n kontrol\u00fcndeki bir a\u011fdan ge\u00e7iyor.<\/p>\n\n\n\n Bu sald\u0131r\u0131n\u0131n nas\u0131l \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 anlamak i\u00e7in 2FA yaz\u0131m\u0131zdaki<\/a> katmanl\u0131 g\u00fcvenlik mant\u0131\u011f\u0131n\u0131 hat\u0131rlay\u0131n. Sadece birinci katman\u0131 (a\u011fa ba\u011flanmak) de\u011fil, ikinci katman\u0131 da (trafi\u011fin \u015fifreli olup olmad\u0131\u011f\u0131n\u0131) kontrol etmek gerekiyor.<\/p>\n\n\n\n Halka a\u00e7\u0131k a\u011fda tam olarak ne tehlikede olabilir?<\/p>\n\n\n\n Oturum \u00e7erezleri (session cookies):<\/strong> Bir siteye giri\u015f yapt\u0131ktan sonra sizi oturum a\u00e7\u0131k tutan k\u00fc\u00e7\u00fck dosyalar. Sald\u0131rgan bu \u00e7erezi \u00e7alabilirse, kullan\u0131c\u0131 ad\u0131-\u015fifrenizi bilmeden o site \u00fczerindeki hesab\u0131n\u0131za eri\u015febilir. Buna “session hijacking” deniyor.<\/p>\n\n\n\n DNS sorgular\u0131:<\/strong> Hangi sitelere gitti\u011finiz bilgisi, HTTPS olsa bile DNS seviyesinde g\u00f6r\u00fcnebilir. Browsing al\u0131\u015fkanl\u0131klar\u0131n\u0131z\u0131, hangi hizmetleri kulland\u0131\u011f\u0131n\u0131z\u0131, hangi saatlerde internette oldu\u011funuzu ortaya \u00e7\u0131karabilir.<\/p>\n\n\n\n \u015eifresiz uygulama trafi\u011fi:<\/strong> Baz\u0131 uygulamalar arka planda \u015fifresiz veri g\u00f6nderebilir. \u00d6zellikle eski veya k\u00f6t\u00fc geli\u015ftirilmi\u015f uygulamalar bu riski ta\u015f\u0131r.<\/p>\n\n\n\n \u0130\u015f e-postalar\u0131 ve belgeler:<\/strong> Kurumsal VPN olmadan i\u015f a\u011flar\u0131na ba\u011flanan \u00e7al\u0131\u015fanlar, \u015firkete ait hassas bilgileri a\u00e7\u0131k bir kanalda iletmi\u015f olabilir.<\/p>\n\n\n\n Veri ihlali yaz\u0131m\u0131zda<\/a> bu t\u00fcr bilgilerin s\u0131zd\u0131\u011f\u0131nda ne kadar h\u0131zl\u0131 de\u011fer kazand\u0131\u011f\u0131n\u0131 anlatt\u0131k. Halka a\u00e7\u0131k Wi-Fi, bu bilgilerin s\u0131zmas\u0131n\u0131n en kolay yollar\u0131ndan biri.<\/p>\n\n\n\n Halka a\u00e7\u0131k Wi-Fi’de en g\u00fcvenilir korunma y\u00f6ntemi VPN (Virtual Private Network) kullanmak. VPN, cihaz\u0131n\u0131zdan \u00e7\u0131kan t\u00fcm trafi\u011fi \u015fifreleyerek VPN sunucusundan ge\u00e7iriyor. Bu sayede ayn\u0131 a\u011fdaki bir sald\u0131rgan trafi\u011fi g\u00f6rse bile i\u00e7eri\u011fini okuyam\u0131yor \u2014 yaln\u0131zca VPN sunucusuna \u015fifreli veri g\u00f6nderdi\u011finizi g\u00f6r\u00fcr.<\/p>\n\n\n\n Ama VPN se\u00e7imi \u00f6nemli. \u00dccretsiz VPN uygulamalar\u0131n\u0131n b\u00fcy\u00fck b\u00f6l\u00fcm\u00fcn\u00fc kullanmak, bir g\u00fcvenlik sorununun yerine ba\u015fka bir g\u00fcvenlik sorununu koymak gibi. Baz\u0131 \u00fccretsiz VPN’ler trafik kayd\u0131 tutuyor, baz\u0131lar\u0131 reklam takibine izin veriyor, kimileri ise k\u00f6t\u00fc ama\u00e7l\u0131 yaz\u0131l\u0131m da\u011f\u0131t\u0131yor.<\/p>\n\n\n\n Electronic Frontier Foundation (eff.org<\/a>) \u2014 dijital haklar ve g\u00fcvenlik alan\u0131nda d\u00fcnyada en sayg\u0131n ba\u011f\u0131ms\u0131z kurulu\u015flardan biri \u2014 VPN se\u00e7imi konusunda kapsaml\u0131 rehberler yay\u0131ml\u0131yor ve g\u00fcvenilir servisler i\u00e7in de\u011ferlendirme kriterleri sunuyor. Bir VPN se\u00e7meden \u00f6nce bu kayna\u011f\u0131 incelemenizi tavsiye ederiz.<\/p>\n\n\n\n VPN olmad\u0131\u011f\u0131 durumlarda da alabilece\u011finiz \u00f6nlemler var:<\/p>\n\n\n\n HTTPS’e dikkat edin:<\/strong> Adres \u00e7ubu\u011funda kilit simgesi ve “https:\/\/” oldu\u011fundan emin olun. \u00d6zellikle giri\u015f, \u00f6deme veya hassas veri giri\u015fi yapaca\u011f\u0131n\u0131z sayfalarda bu kontrol vazge\u00e7ilmez.<\/p>\n\n\n\n Otomatik ba\u011flanmay\u0131 kapat\u0131n:<\/strong> Cihaz\u0131n\u0131z\u0131n bilinen a\u011flara otomatik ba\u011flanma \u00f6zelli\u011fini devre d\u0131\u015f\u0131 b\u0131rak\u0131n. “K\u00f6t\u00fc ikiz” sald\u0131r\u0131lar\u0131n\u0131n i\u015fe yaramas\u0131n\u0131n ba\u015fl\u0131ca nedeni bu otomatik ba\u011flanma.<\/p>\n\n\n\n Hassas i\u015flemler i\u00e7in mobil veri kullan\u0131n:<\/strong> Banka uygulamas\u0131, e-posta, i\u015f belgeleri \u2014 bunlar i\u00e7in halka a\u00e7\u0131k Wi-Fi yerine telefonun mobil veri ba\u011flant\u0131s\u0131n\u0131 tercih edin.<\/p>\n\n\n\n Dosya payla\u015f\u0131m\u0131n\u0131 kapat\u0131n:<\/strong> A\u011fa ba\u011fland\u0131\u011f\u0131n\u0131zda i\u015fletim sisteminin dosya payla\u015f\u0131m\u0131 \u00f6zelli\u011finin kapal\u0131 oldu\u011fundan emin olun.<\/p>\n\n\n\n DNS over HTTPS (DoH) etkinle\u015ftirin:<\/strong> Modern taray\u0131c\u0131lar ve i\u015fletim sistemleri DNS sorgular\u0131n\u0131 da \u015fifreleyen DoH’u destekliyor. Bu, browsing al\u0131\u015fkanl\u0131klar\u0131n\u0131z\u0131n g\u00f6r\u00fcn\u00fcrl\u00fc\u011f\u00fcn\u00fc azalt\u0131r.<\/p>\n\n\n\n 2FA aktif olsun:<\/strong> Hesaplar\u0131n\u0131z\u0131n t\u00fcm\u00fcnde iki fakt\u00f6rl\u00fc do\u011frulama<\/a> a\u00e7\u0131k olsun. Bir sald\u0131rgan oturum \u00e7erezinizi \u00e7almay\u0131 ba\u015farsa bile, \u015fifrenizi ele ge\u00e7irse bile, 2FA olmadan oturumu devralmak \u00e7ok daha zor.<\/p>\n\n\n\n Bireysel riskten \u00f6te, kurumsal tarafta halka a\u00e7\u0131k Wi-Fi \u00e7ok daha b\u00fcy\u00fck bir endi\u015fe. Uzaktan \u00e7al\u0131\u015fanlar\u0131n kafe ya da ortak \u00e7al\u0131\u015fma alanlar\u0131nda kurumsal e-posta, proje y\u00f6netim ara\u00e7lar\u0131 veya ERP sistemlerine ba\u011flanmas\u0131 \u2014 bu senaryolar\u0131n her biri potansiyel bir veri s\u0131z\u0131nt\u0131s\u0131 riski ta\u015f\u0131yor.<\/p>\n\n\n\n Kurumsal d\u00fczeyde bu riski y\u00f6netmenin standard\u0131, t\u00fcm uzak eri\u015fimi zorunlu kurumsal VPN \u00fczerinden y\u00f6nlendirmek. \u015eifre y\u00f6neticileri yaz\u0131m\u0131zda<\/a> ki\u015fisel g\u00fcvenli\u011fin katmanl\u0131 yap\u0131s\u0131ndan s\u00f6z ettik; kurumsal g\u00fcvenlikte de ayn\u0131 mant\u0131k ge\u00e7erli: tek bir \u00f6nlem yeterli de\u011fil, katmanlar bir arada \u00e7al\u0131\u015fmal\u0131.<\/p>\n\n\n\n Halka a\u00e7\u0131k Wi-Fi kullanmak kolay, \u00fccretsiz ve pratik. Ama bu kolayl\u0131k, arka planda ciddi riskler ta\u015f\u0131yor. \u00c7o\u011fu kullan\u0131c\u0131n\u0131n bu risklere maruz kald\u0131\u011f\u0131n\u0131 bile bilmemesi, sald\u0131rganlar i\u00e7in en b\u00fcy\u00fck avantaj.<\/p>\n","protected":false},"excerpt":{"rendered":" Havaliman\u0131nda bekliyorsunuz, kafede \u00e7al\u0131\u015f\u0131yorsunuz ya da otelde bir toplant\u0131ya ba\u011flanmak istiyorsunuz. Telefon veya bilgisayar\u0131n Wi-Fi listesi a\u00e7\u0131l\u0131yor: onlarca a\u011f g\u00f6r\u00fcn\u00fcyor. “AirportFreeWifi”, “Starbucks_Guest”, “Hotel_Lobby” \u2014 birine dokunuyorsunuz, internet a\u00e7\u0131l\u0131yor, hayat devam ediyor. Ama arka planda, tamamen fark\u0131nda olmadan, verileriniz son derece savunmas\u0131z bir ortama girmi\u015f olabilir. Halka a\u00e7\u0131k Wi-Fi a\u011flar\u0131, siber g\u00fcvenlik d\u00fcnyas\u0131n\u0131n en kadim ve … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-78","post","type-post","status-publish","format-standard","hentry","category-dijital-guvenlik"],"_links":{"self":[{"href":"https:\/\/hocabul.net\/index.php?rest_route=\/wp\/v2\/posts\/78","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hocabul.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hocabul.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hocabul.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hocabul.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=78"}],"version-history":[{"count":1,"href":"https:\/\/hocabul.net\/index.php?rest_route=\/wp\/v2\/posts\/78\/revisions"}],"predecessor-version":[{"id":79,"href":"https:\/\/hocabul.net\/index.php?rest_route=\/wp\/v2\/posts\/78\/revisions\/79"}],"wp:attachment":[{"href":"https:\/\/hocabul.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=78"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hocabul.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=78"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hocabul.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=78"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n\n\n\nMan-in-the-Middle: Ortadaki Adam Sizi Dinliyor<\/h2>\n\n\n\n
\n
\n\n\n\nK\u00f6t\u00fc \u0130kiz A\u011flar: Sahte Eri\u015fim Noktalar\u0131<\/h2>\n\n\n\n
\n\n\n\nHangi Bilgiler Risk Alt\u0131nda?<\/h2>\n\n\n\n
\n\n\n\nVPN: En Etkili Kalkan<\/h2>\n\n\n\n
\n\n\n\nPratik \u00d6nlemler: VPN Olmadan da Yapabilecekleriniz<\/h2>\n\n\n\n
\n\n\n\n\u0130\u015f Ortam\u0131 Riski: Kurumsal Verilerin A\u00e7\u0131k A\u011fdaki Ser\u00fcveni<\/h2>\n\n\n\n
\n\n\n\nSonu\u00e7: Kolayl\u0131k ile G\u00fcvenlik Aras\u0131ndaki Denge<\/h2>\n\n\n\n