{"id":7426,"date":"2019-11-27T14:29:34","date_gmt":"2019-11-27T11:29:34","guid":{"rendered":"https:\/\/www.kaspersky.com.tr\/blog\/?p=7426"},"modified":"2019-11-27T14:29:34","modified_gmt":"2019-11-27T11:29:34","slug":"vnc-vulnerabilities","status":"publish","type":"post","link":"https:\/\/www.kaspersky.com.tr\/blog\/vnc-vulnerabilities\/7426\/","title":{"rendered":"VNC uzaktan eri\u015fim g\u00fcvenlik a\u00e7\u0131klar\u0131"},"content":{"rendered":"<p>Uzaktan eri\u015fim kolayl\u0131k sa\u011flar ve bazen zaruridir. \u00d6te yandan, \u00f6zellikle de kulland\u0131\u011f\u0131n\u0131z uzaktan eri\u015fim ara\u00e7lar\u0131nda g\u00fcvenlik a\u00e7\u0131klar\u0131 varsa, kurumsal alt yap\u0131n\u0131zda davetsiz misafirler i\u00e7in giri\u015f noktalar\u0131 sa\u011flayabilirler.<\/p>\n<h2>VNC g\u00fcvenlik a\u00e7\u0131klar\u0131<\/h2>\n<p>ICS CERT uzmanlar\u0131m\u0131z bir\u00e7ok VNC (Sanal A\u011f Bilgi \u0130\u015fleme) uygulamas\u0131n\u0131 inceledi. VNC; teknik destek, ekipman izleme, uzaktan \u00f6\u011frenme ve di\u011fer ama\u00e7larla yayg\u0131n olarak kullan\u0131lan bir uzaktan eri\u015fim sistemidir. Bu uygulamalar\u0131n toplam 37 g\u00fcvenlik a\u00e7\u0131\u011f\u0131 i\u00e7erdi\u011fi bulundu. Bu g\u00fcvenlik a\u00e7\u0131klar\u0131ndan baz\u0131lar\u0131 1999\u2019dan bu yana fark edilmemi\u015fti.<\/p>\n<p>VNC sistemleri kullanan cihazlar\u0131n say\u0131s\u0131n\u0131 net olarak s\u00f6ylemek zor, fakat Shodan arama motorundan gelen verilere g\u00f6re 600.000\u2019den fazla VNC sunucusuna \u00e7evrimi\u00e7i olarak <a href=\"https:\/\/www.shodan.io\/search?query=%22rfb%22\" target=\"_blank\" rel=\"noopener nofollow\">eri\u015filebiliyor<\/a>. Ger\u00e7ek say\u0131n\u0131n bunun \u00e7ok \u00fcst\u00fcnde oldu\u011fu d\u00fc\u015f\u00fcn\u00fcl\u00fcyor.<\/p>\n<h2>G\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 nerede bulduk<\/h2>\n<p>Uzmanlar\u0131m\u0131z yayg\u0131n olarak kullan\u0131lan d\u00f6rt a\u00e7\u0131k kodlu VNC uygulamas\u0131n\u0131 inceledi:<\/p>\n<ul>\n<li>LibVNC: Bir k\u00fct\u00fcphane, yani geli\u015ftiricilerin temel alarak uygulama yaratabildi\u011fi bir dizi haz\u0131r kod par\u00e7ac\u0131\u011f\u0131. LibVNC, iOS ve Android mobil cihazlarda kullan\u0131ld\u0131\u011f\u0131 kadar, \u00f6rne\u011fin sanal makinelere uzaktan ba\u011flant\u0131 sa\u011flayan sistemlerde de kullan\u0131l\u0131yor.<\/li>\n<li>TightVNC 1.X: End\u00fcstriyel otomasyon sistemi sat\u0131c\u0131lar\u0131 taraf\u0131ndan insan-makine aray\u00fczlerine (HMI) ba\u011flanmak i\u00e7in \u00f6nerilen bir uygulama.<\/li>\n<li>TurboVNC: Grafik, 3D ve video nesneleri ile uzaktan \u00e7al\u0131\u015fmak i\u00e7in kullan\u0131lan bir VNC uygulamas\u0131.<\/li>\n<li>UltraVNC: \u00d6zel olarak Windows i\u00e7in yap\u0131lm\u0131\u015f bir VNC \u00e7e\u015fidi. Ayr\u0131ca HMI\u2019lara ba\u011flanmak i\u00e7in end\u00fcstriyel \u00fcretimde de yayg\u0131n olarak kullan\u0131l\u0131yor.<\/li>\n<\/ul>\n<p>D\u00f6rt sistemde de hatalar tespit edildi: TurboVNC\u2019de bir, TightVNC\u2019de d\u00f6rt, LibVNC\u2019de on, UltraVNC\u2019de ise tam 22 tane.<\/p>\n<h2>G\u00fcvenlik a\u00e7\u0131klar\u0131 neler ve nas\u0131l k\u00f6t\u00fcye kullan\u0131labilirler<\/h2>\n<p>VNC uygulamalar\u0131 iki b\u00f6l\u00fcmden olu\u015fur: \u00c7al\u0131\u015fan\u0131n\u0131z\u0131n uzaktan ba\u011fland\u0131\u011f\u0131 bilgisayarda kurulu bir sunucu ve ba\u011flanan cihazda \u00e7al\u0131\u015fan bir istemci. Genellikle daha basit oldu\u011fu i\u00e7in daha az hata bar\u0131nd\u0131ran sunucu taraf\u0131nda g\u00fcvenlik a\u00e7\u0131\u011f\u0131 \u00e7ok daha az g\u00f6r\u00fcl\u00fcr. Buna ra\u011fmen CERT uzmanlar\u0131m\u0131z incelenen uygulamalar\u0131n her iki k\u0131sm\u0131nda da hatalar buldu. Bununla birlikte \u00e7o\u011fu durumda yetkilendirme olmaks\u0131z\u0131n sunucuya sald\u0131r\u0131lmak imkans\u0131z olurdu.<\/p>\n<p>Hatalar\u0131n tamam\u0131 hatal\u0131 bellek kullan\u0131m\u0131yla ba\u011flant\u0131l\u0131yd\u0131. Bunlar\u0131n k\u00f6t\u00fcye kullan\u0131lmas\u0131 yaln\u0131zca bozulmaya ve hizmet d\u0131\u015f\u0131 kalmaya yol a\u00e7\u0131yordu; bu, g\u00f6rece daha iyi bir sonu\u00e7tu. Daha ciddi vakalarda ise sald\u0131rganlar cihazdaki bilgilere yetkisiz eri\u015fim elde edebiliyor veya kurban\u0131n sistemine k\u00f6t\u00fc ama\u00e7l\u0131 yaz\u0131l\u0131m b\u0131rakabiliyordu.<\/p>\n<h2>G\u00fcvenlik a\u00e7\u0131klar\u0131ndan baz\u0131lar\u0131 tamir edildi, baz\u0131lar\u0131 edilmedi<\/h2>\n<p>CERT uzmanlar\u0131m\u0131z, hatalar\u0131 bu k\u00fct\u00fcphanelerin ve uygulamar\u0131n geli\u015ftiricilerine bildirdi. Hatalar\u0131n \u00e7o\u011fu giderildi bile. Biri hari\u00e7: TightVNC\u2019nin yarat\u0131c\u0131lar\u0131 sistemlerinin ilk s\u00fcr\u00fcm\u00fcn\u00fc art\u0131k desteklemiyor ve bu s\u00fcr\u00fcmde tespit edilen g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 tamir etmeyi kabul etmediler. Bu, ba\u015fka bir VNC platformuna ge\u00e7meyi d\u00fc\u015f\u00fcnmek i\u00e7in yeterli bir sebep olabilir.<\/p>\n<p>Dahas\u0131, pek \u00e7ok a\u00e7\u0131k kaynakl\u0131 projede oldu\u011fu gibi, g\u00fcvenlik a\u00e7\u0131\u011f\u0131 bulunan kod, geli\u015ftirilen \u00e7ok say\u0131da ba\u015fka programda da kullan\u0131ld\u0131 ve t\u00fcm geli\u015ftiriciler geli\u015ftirdikleri \u00fcr\u00fcnde kulland\u0131klar\u0131 par\u00e7alar hakk\u0131nda g\u00fcncellemeleri takip etmiyor. Bu tarz programlar, geli\u015ftiricileri kodu g\u00fcncelleyene kadar g\u00fcvenlik a\u00e7\u0131\u011f\u0131 i\u00e7ermeye devam edecek. Bunu s\u00f6ylemek bizi \u00fcz\u00fcyor ama baz\u0131 geli\u015ftiriciler bu g\u00fcncellemeyi hi\u00e7 yapmayabilir de.<\/p>\n<h2>\u0130\u015fletmeler nas\u0131l eyleme ge\u00e7meli?<\/h2>\n<p>G\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131n listesini teknik ayr\u0131nt\u0131lar\u0131yla birlikte <a href=\"https:\/\/ics-cert.kaspersky.com\/reports\/2019\/11\/22\/vnc-vulnerability-research\/\" target=\"_blank\" rel=\"noopener\">Kaspersky ICS CERT web sitesinde yay\u0131nlanan raporda<\/a> bulabilirsiniz. Meslekta\u015flar\u0131m\u0131z end\u00fcstriyel kurulu\u015flarda VNC kullan\u0131m\u0131na odaklanm\u0131\u015f olsa da tehditler bu teknolojiyi kullanan t\u00fcm i\u015fletmeler i\u00e7in ge\u00e7erli.<\/p>\n<p>Siber su\u00e7lular\u0131n bu g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 size kar\u015f\u0131 kullanmas\u0131n\u0131 \u00f6nlemek i\u00e7in altyap\u0131n\u0131zdaki uzaktan eri\u015fim programlar\u0131n\u0131 izlemenizi \u00f6neriyoruz.<\/p>\n<ul>\n<li>Hangi cihazlar\u0131n uzaktan ba\u011flant\u0131 kurabildi\u011fini kontrol edin ve gerekli de\u011filse uzaktan ba\u011flant\u0131lar\u0131 engelleyin.<\/li>\n<li>Yaln\u0131zca VNC de\u011fil, t\u00fcm uzaktan eri\u015fim uygulamalar\u0131n\u0131n envanterini \u00e7\u0131kar\u0131n ve s\u00fcr\u00fcmlerinin g\u00fcncel olup olmad\u0131\u011f\u0131n\u0131 kontrol edin. G\u00fcvenilirlikleri hakk\u0131nda \u015f\u00fcpheleriniz varsa kullanmay\u0131 b\u0131rak\u0131n. Kullanmaya devam edecekseniz en son s\u00fcr\u00fcme y\u00fckseltti\u011finizden emin olun.<\/li>\n<li>VNC sunucular\u0131n\u0131z\u0131 g\u00fc\u00e7l\u00fc bir parolayla koruyun. Bu, sald\u0131r\u0131lar\u0131 zorla\u015ft\u0131racakt\u0131r.<\/li>\n<li>G\u00fcvenilmeyen ya da test edilmemi\u015f VNC sunucular\u0131na ba\u011flanmay\u0131n.<\/li>\n<li>End\u00fcstriyel kurulu\u015f ortamlar\u0131nda Kaspersky Industrial CyberSecurity gibi end\u00fcstriyel otomasyon sistemleri i\u00e7in \u00f6zel olarak geli\u015ftirilmi\u015f bir g\u00fcvenlik \u00e7\u00f6z\u00fcm\u00fc kullan\u0131n.<\/li>\n<li>\u0130\u015fletmenizi korumak i\u00e7in g\u00fc\u00e7l\u00fc bir g\u00fcvenlik \u00e7\u00f6z\u00fcm\u00fc kullan\u0131n. <a href=\"https:\/\/kas.pr\/kdkesbtr\" target=\"_blank\" rel=\"noopener\">Kaspersky Endpoint Security for Business<\/a> bu a\u00e7\u0131dan m\u00fckemmel bir tercih.<\/li>\n<\/ul>\n<input type=\"hidden\" class=\"category_for_banner\" value=\"kesb-trial-leadgen\">\n","protected":false},"excerpt":{"rendered":"<p>ICS CERT uzmanlar\u0131m\u0131z d\u00f6rt VNC uygulamas\u0131nda 37 g\u00fcvenlik a\u00e7\u0131\u011f\u0131 buldu. Geli\u015ftiriciler a\u00e7\u0131klar\u0131n \u00e7o\u011funu tamir etse de bir k\u0131sm\u0131 hala duruyor.<\/p>\n","protected":false},"author":2484,"featured_media":7431,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1726,1194],"tags":[790,537,1953,2072],"class_list":{"0":"post-7426","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-enterprise","8":"category-business","9":"tag-guvenlik-aciklari","10":"tag-tehditler","11":"tag-uzaktan-erisim","12":"tag-vnc"},"hreflang":[{"hreflang":"tr","url":"https:\/\/www.kaspersky.com.tr\/blog\/vnc-vulnerabilities\/7426\/"},{"hreflang":"en-in","url":"https:\/\/www.kaspersky.co.in\/blog\/vnc-vulnerabilities\/18267\/"},{"hreflang":"en-ae","url":"https:\/\/me-en.kaspersky.com\/blog\/vnc-vulnerabilities\/15158\/"},{"hreflang":"en-us","url":"https:\/\/usa.kaspersky.com\/blog\/vnc-vulnerabilities\/19962\/"},{"hreflang":"en-gb","url":"https:\/\/www.kaspersky.co.uk\/blog\/vnc-vulnerabilities\/18358\/"},{"hreflang":"es-mx","url":"https:\/\/latam.kaspersky.com\/blog\/vnc-vulnerabilities\/16717\/"},{"hreflang":"es","url":"https:\/\/www.kaspersky.es\/blog\/vnc-vulnerabilities\/20680\/"},{"hreflang":"it","url":"https:\/\/www.kaspersky.it\/blog\/vnc-vulnerabilities\/19423\/"},{"hreflang":"ru","url":"https:\/\/www.kaspersky.ru\/blog\/vnc-vulnerabilities\/25759\/"},{"hreflang":"x-default","url":"https:\/\/www.kaspersky.com\/blog\/vnc-vulnerabilities\/31462\/"},{"hreflang":"pt-br","url":"https:\/\/www.kaspersky.com.br\/blog\/vnc-vulnerabilities\/13786\/"},{"hreflang":"pl","url":"https:\/\/plblog.kaspersky.com\/vnc-vulnerabilities\/11715\/"},{"hreflang":"de","url":"https:\/\/www.kaspersky.de\/blog\/vnc-vulnerabilities\/21577\/"},{"hreflang":"ja","url":"https:\/\/blog.kaspersky.co.jp\/vnc-vulnerabilities\/26066\/"},{"hreflang":"nl","url":"https:\/\/www.kaspersky.nl\/blog\/vnc-vulnerabilities\/24849\/"},{"hreflang":"ru-kz","url":"https:\/\/blog.kaspersky.kz\/vnc-vulnerabilities\/19698\/"},{"hreflang":"en-au","url":"https:\/\/www.kaspersky.com.au\/blog\/vnc-vulnerabilities\/25573\/"},{"hreflang":"en-za","url":"https:\/\/www.kaspersky.co.za\/blog\/vnc-vulnerabilities\/25411\/"}],"acf":[],"banners":"","maintag":{"url":"https:\/\/www.kaspersky.com.tr\/blog\/tag\/guvenlik-aciklari\/","name":"g\u00fcvenlik a\u00e7\u0131klar\u0131"},"_links":{"self":[{"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/posts\/7426","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/users\/2484"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/comments?post=7426"}],"version-history":[{"count":3,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/posts\/7426\/revisions"}],"predecessor-version":[{"id":7432,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/posts\/7426\/revisions\/7432"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/media\/7431"}],"wp:attachment":[{"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/media?parent=7426"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/categories?post=7426"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kaspersky.com.tr\/blog\/wp-json\/wp\/v2\/tags?post=7426"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}