{"id":477282,"date":"2023-08-09T09:10:23","date_gmt":"2023-08-09T09:10:23","guid":{"rendered":""},"modified":"2023-11-29T15:03:54","modified_gmt":"2023-11-29T15:03:54","slug":"format-string-attack","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/tr\/wiki\/format-string-attack\/","title":{"rendered":"Dize sald\u0131r\u0131s\u0131n\u0131 bi\u00e7imlendir"},"content":{"rendered":"

Bi\u00e7im dizesi sald\u0131r\u0131s\u0131, bilgisayar programlamada meydana gelen bir t\u00fcr g\u00fcvenlik a\u00e7\u0131\u011f\u0131d\u0131r. Sald\u0131rgan\u0131n, program\u0131n bi\u00e7imlendirilmi\u015f giri\u015f\/\u00e7\u0131k\u0131\u015f i\u015flevlerini i\u015fleme bi\u00e7iminden yararlanmas\u0131na olanak tan\u0131r. Sald\u0131rgan bu g\u00fcvenlik a\u00e7\u0131\u011f\u0131n\u0131 kullanarak hassas verileri okuyabilir, bellek i\u00e7eri\u011fini de\u011fi\u015ftirebilir ve hatta hedef sistemde rastgele kod \u00e7al\u0131\u015ft\u0131rabilir. Format dizesi sald\u0131r\u0131lar\u0131, sistem b\u00fct\u00fcnl\u00fc\u011f\u00fcn\u00fc ve gizlili\u011fini tehlikeye atma potansiyelleri nedeniyle yaz\u0131l\u0131m geli\u015ftiricileri ve sistem y\u00f6neticileri i\u00e7in \u00f6nemli bir endi\u015fe kayna\u011f\u0131 olmu\u015ftur.<\/p>\n

Format String Attack'\u0131n k\u00f6keninin tarihi ve bundan ilk s\u00f6z<\/h2>\n

Bi\u00e7im dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131 kavram\u0131 ilk olarak 1990'lar\u0131n sonlar\u0131nda g\u00fcn \u0131\u015f\u0131\u011f\u0131na \u00e7\u0131kt\u0131. 2000 y\u0131l\u0131nda Kostya Kortchinsky'nin "Bi\u00e7im Dizgesi G\u00fcvenlik A\u00e7\u0131klar\u0131ndan Yararlanma" ba\u015fl\u0131kl\u0131 makalesiyle pop\u00fcler hale getirildi. Makalede bu g\u00fcvenlik a\u00e7\u0131\u011f\u0131ndan yararlan\u0131lmas\u0131 ayr\u0131nt\u0131l\u0131 olarak tart\u0131\u015f\u0131ld\u0131 ve sistemler \u00fczerindeki potansiyel etkisi g\u00f6sterildi. O zamandan bu yana, format dizesi sald\u0131r\u0131lar\u0131 kapsaml\u0131 bir \u015fekilde incelendi ve bu, yaz\u0131l\u0131m geli\u015ftirmede daha iyi anla\u015f\u0131lmas\u0131na ve g\u00fcvenlik uygulamalar\u0131n\u0131n iyile\u015ftirilmesine yol a\u00e7t\u0131.<\/p>\n

Format String Sald\u0131r\u0131s\u0131 hakk\u0131nda detayl\u0131 bilgi<\/h2>\n

Bi\u00e7im dizesi sald\u0131r\u0131lar\u0131, bir sald\u0131rgan\u0131n bi\u00e7imlendirilmi\u015f bir giri\u015f\/\u00e7\u0131k\u0131\u015f i\u015flevindeki bi\u00e7im dizesi parametresini kontrol edebilmesi durumunda ger\u00e7ekle\u015fir. Bu i\u015flevler, \u00f6rne\u011fin printf()<\/code> Ve sprintf()<\/code>, verileri bi\u00e7imlendirmek ve yazd\u0131rmak i\u00e7in yayg\u0131n olarak kullan\u0131l\u0131r. C ve C++ gibi dillerde geli\u015ftiricilerin yer tutucular\u0131 belirlemesine olanak tan\u0131r (\u00f6r. %s<\/code> dizeler i\u00e7in, %d<\/code> tamsay\u0131lar i\u00e7in) ve kar\u015f\u0131l\u0131k gelen de\u011ferlerin g\u00f6r\u00fcnt\u00fclenmesini sa\u011flar. G\u00fcvenlik a\u00e7\u0131\u011f\u0131, bir program\u0131n kullan\u0131c\u0131 taraf\u0131ndan kontrol edilen verileri uygun do\u011frulama olmadan bi\u00e7im dizesi olarak ge\u00e7irmesi durumunda ortaya \u00e7\u0131kar ve bu da istenmeyen sonu\u00e7lara yol a\u00e7ar.<\/p>\n

Format String Attack'\u0131n i\u00e7 yap\u0131s\u0131 ve nas\u0131l \u00e7al\u0131\u015ft\u0131\u011f\u0131<\/h2>\n

Bi\u00e7im dizesi sald\u0131r\u0131s\u0131n\u0131n nas\u0131l \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 anlamak i\u00e7in bi\u00e7imlendirilmi\u015f giri\u015f\/\u00e7\u0131k\u0131\u015f i\u015flevlerinin i\u00e7 i\u015fleyi\u015fini kavramak \u00f6nemlidir. C gibi dillerde, bi\u00e7imlendirilmi\u015f yazd\u0131rma i\u015flevleri kendilerine iletilen ba\u011f\u0131ms\u0131z de\u011fi\u015fkenlere eri\u015fmek i\u00e7in y\u0131\u011f\u0131n\u0131 kullan\u0131r. Bir geli\u015ftirici bir bi\u00e7im dizesi sa\u011flad\u0131\u011f\u0131nda, i\u015flev bunun \u00fczerinden yinelenir ve bi\u00e7im belirticilerini arar (\u00f6rn. %s<\/code>, %d<\/code>). Fonksiyon, bulunan her belirtici i\u00e7in y\u0131\u011f\u0131nda kar\u015f\u0131l\u0131k gelen bir arg\u00fcman bekler.<\/p>\n

G\u00fcvenlik a\u00e7\u0131\u011f\u0131 bulunan bir programda, bir sald\u0131rgan bi\u00e7im dizesini kontrol edebiliyorsa, a\u015fa\u011f\u0131dakilerden yararlanarak program\u0131n belle\u011fini de\u011fi\u015ftirebilir:<\/p>\n

    \n
  1. Haf\u0131za Okuma<\/strong>: Gibi bi\u00e7im belirticileri kullanarak %x<\/code> veya %s<\/code>sald\u0131rgan, hassas bilgiler i\u00e7erebilecek y\u0131\u011f\u0131n\u0131n veya di\u011fer bellek b\u00f6lgelerinin i\u00e7eri\u011fini s\u0131zd\u0131rabilir.<\/li>\n
  2. Haf\u0131za Yazma<\/strong>: Gibi bi\u00e7im belirticileri %n<\/code> Sald\u0131rgan\u0131n ilgili arg\u00fcman\u0131n i\u015faret etti\u011fi haf\u0131za adresine veri yazmas\u0131na izin verir. Bu, de\u011fi\u015fkenleri, i\u015flev i\u015faret\u00e7ilerini ve hatta program\u0131n kodunu de\u011fi\u015ftirmek i\u00e7in k\u00f6t\u00fcye kullan\u0131labilir.<\/li>\n
  3. Keyfi Kod Y\u00fcr\u00fctme<\/strong>: Sald\u0131rgan bi\u00e7im dizesini kontrol edebilir ve do\u011fru arg\u00fcmanlar\u0131 sa\u011flayabilirse, kullanarak rastgele kod \u00e7al\u0131\u015ft\u0131rabilir. %n<\/code> bir i\u015flev i\u015faret\u00e7isine yazmak ve ard\u0131ndan y\u00fcr\u00fct\u00fclmesini tetiklemek i\u00e7in.<\/li>\n<\/ol>\n

    Format String Attack'\u0131n temel \u00f6zelliklerinin analizi<\/h2>\n

    Bi\u00e7im dizesi sald\u0131r\u0131s\u0131n\u0131n temel \u00f6zellikleri \u015funlard\u0131r:<\/p>\n

      \n
    1. Dize Denetimini Bi\u00e7imlendir<\/strong>: Sald\u0131rgan, \u00e7\u0131kt\u0131 bi\u00e7imini belirleyen ve bellek eri\u015fimini de\u011fi\u015ftirebilen bi\u00e7im dizesini kontrol edebilir.<\/li>\n
    2. Y\u0131\u011f\u0131n Tabanl\u0131 S\u00f6m\u00fcr\u00fc<\/strong>: Bi\u00e7imlendirilmi\u015f giri\u015f\/\u00e7\u0131k\u0131\u015f i\u015flevleri arg\u00fcmanlara eri\u015fmek i\u00e7in onu kulland\u0131\u011f\u0131ndan, bi\u00e7im dizesi sald\u0131r\u0131lar\u0131 genellikle y\u0131\u011f\u0131n\u0131 hedefler.<\/li>\n
    3. Bellek Manip\u00fclasyonu<\/strong>: Sald\u0131rganlar, bi\u00e7im belirticileri arac\u0131l\u0131\u011f\u0131yla bellek adreslerini okuyabilir veya yazabilir; bu da potansiyel olarak bilgilerin a\u00e7\u0131\u011fa \u00e7\u0131kmas\u0131na veya kod y\u00fcr\u00fct\u00fclmesine yol a\u00e7abilir.<\/li>\n<\/ol>\n

      Format Dizesi Sald\u0131r\u0131s\u0131 T\u00fcrleri<\/h2>\n

      Bi\u00e7im dizesi sald\u0131r\u0131lar\u0131 iki ana t\u00fcre ayr\u0131labilir:<\/p>\n

        \n
      1. Sald\u0131r\u0131lar\u0131 Okumak<\/strong>: Bu sald\u0131r\u0131lar, program\u0131n belle\u011finden y\u0131\u011f\u0131n adresleri veya parola verileri gibi hassas bilgileri okumak i\u00e7in bi\u00e7im belirticilerden yararlanmaya odaklan\u0131r.<\/li>\n
      2. Sald\u0131r\u0131 Yazma<\/strong>: Bu sald\u0131r\u0131larda ama\u00e7, belirli bellek adreslerine veri yazmak i\u00e7in format belirleyicileri kullanarak belle\u011fi manip\u00fcle etmek ve sald\u0131rgan\u0131n de\u011fi\u015fkenleri veya i\u015flev i\u015faret\u00e7ilerini de\u011fi\u015ftirmesine olanak sa\u011flamakt\u0131r.<\/li>\n<\/ol>\n

        Format dizesi sald\u0131r\u0131lar\u0131n\u0131n t\u00fcrlerini \u00f6zetleyen bir tablo a\u015fa\u011f\u0131da verilmi\u015ftir:<\/p>\n\n\n\n\n\n\n
        Sald\u0131r\u0131 T\u00fcr\u00fc<\/th>\nTan\u0131m<\/th>\n<\/tr>\n<\/thead>\n
        Sald\u0131r\u0131lar\u0131 Okumak<\/td>\nBelle\u011fi okumak i\u00e7in format belirticilerinden yararlanma<\/td>\n<\/tr>\n
        Sald\u0131r\u0131 Yazma<\/td>\nBellek yazmak i\u00e7in format belirticilerden yararlanma<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        Format String Attack'\u0131 kullanma yollar\u0131, sorunlar ve \u00e7\u00f6z\u00fcmleri<\/h2>\n

        Format String Attack'\u0131 kullanma yollar\u0131<\/h3>\n

        Sald\u0131rganlar, a\u015fa\u011f\u0131dakiler de dahil olmak \u00fczere \u00e7e\u015fitli senaryolarda format dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131ndan yararlanabilir:<\/p>\n

          \n
        1. Web uygulamalar\u0131<\/strong>: Web uygulamalar\u0131, kullan\u0131c\u0131 taraf\u0131ndan sa\u011flanan verileri uygun do\u011frulama olmadan bi\u00e7im dizeleri olarak kullan\u0131rsa, sald\u0131rganlar uygulamay\u0131 veya temel sunucuyu tehlikeye atmak i\u00e7in bundan yararlanabilir.<\/li>\n
        2. Komut Sat\u0131r\u0131 Aray\u00fczleri<\/strong>: Bi\u00e7im dizeleri olu\u015fturmak i\u00e7in komut sat\u0131r\u0131 ba\u011f\u0131ms\u0131z de\u011fi\u015fkenlerini kullanan programlar, kullan\u0131c\u0131 giri\u015fini do\u011frulamazlarsa sald\u0131r\u0131lara kar\u015f\u0131 savunmas\u0131zd\u0131r.<\/li>\n
        3. Kay\u0131t Mekanizmalar\u0131<\/strong>: G\u00fcnl\u00fc\u011fe kaydetme mekanizmalar\u0131ndaki format dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131, sald\u0131rganlara sistem hakk\u0131nda de\u011ferli bilgiler sa\u011flayabilir ve daha sonraki sald\u0131r\u0131lar\u0131 kolayla\u015ft\u0131rabilir.<\/li>\n<\/ol>\n

          Sorunlar ve \u00c7\u00f6z\u00fcmler<\/h3>\n
            \n
          1. Yetersiz Giri\u015f Do\u011frulamas\u0131<\/strong>: Bi\u00e7im dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131n birincil nedeni, yetersiz giri\u015f do\u011frulamas\u0131d\u0131r. Geli\u015ftiriciler, kullan\u0131c\u0131 kontroll\u00fc giri\u015fi bir bi\u00e7im dizesi olarak kullanmadan \u00f6nce do\u011frulamal\u0131d\u0131r.<\/li>\n
          2. Bi\u00e7im Dizelerinin S\u0131n\u0131rl\u0131 Kullan\u0131m\u0131<\/strong>: M\u00fcmk\u00fcn oldu\u011funda geli\u015ftiriciler, kullan\u0131c\u0131 taraf\u0131ndan kontrol edilen verilerle bi\u00e7im dizeleri kullanmaktan ka\u00e7\u0131nmal\u0131d\u0131r. Bunun yerine, dize birle\u015ftirme veya kitapl\u0131klar\u0131 s\u0131k\u0131 giri\u015f denetimleriyle bi\u00e7imlendirme gibi daha g\u00fcvenli alternatifler kullanmay\u0131 d\u00fc\u015f\u00fcn\u00fcn.<\/li>\n
          3. Derleyici G\u00fcvenlik \u00d6zellikleri<\/strong>: Modern derleyiciler a\u015fa\u011f\u0131daki gibi g\u00fcvenlik mekanizmalar\u0131 sunar: -fstack-protector<\/code> Bi\u00e7im dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 tespit etmek ve \u00f6nlemek i\u00e7in GCC'deki se\u00e7enek. Bu t\u00fcr \u00f6zelliklerin kullan\u0131lmas\u0131 riski azaltabilir.<\/li>\n<\/ol>\n

            Ana \u00f6zellikler ve benzer terimlerle kar\u015f\u0131la\u015ft\u0131rmalar<\/h2>\n\n\n\n\n\n\n\n\n
            Terim<\/th>\nTan\u0131m<\/th>\n<\/tr>\n<\/thead>\n
            Dize Sald\u0131r\u0131s\u0131n\u0131 Bi\u00e7imlendir<\/td>\nBelle\u011fi y\u00f6netmek i\u00e7in format belirticilerden yararlanma<\/td>\n<\/tr>\n
            Arabellek Ta\u015fmas\u0131<\/td>\nBir arabelle\u011fin s\u0131n\u0131rlar\u0131n\u0131n \u00f6tesinde veri yazma<\/td>\n<\/tr>\n
            SQL Enjeksiyonu<\/td>\nK\u00f6t\u00fc ama\u00e7l\u0131 girdilerle SQL sorgular\u0131ndan yararlanma<\/td>\n<\/tr>\n
            Siteler Aras\u0131 Komut Dosyas\u0131 \u00c7al\u0131\u015ft\u0131rma<\/td>\nK\u00f6t\u00fc ama\u00e7l\u0131 komut dosyalar\u0131n\u0131 web uygulamalar\u0131na enjekte etme<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

            Format dizesi sald\u0131r\u0131lar\u0131 ile di\u011fer g\u00fcvenlik a\u00e7\u0131klar\u0131 aras\u0131nda baz\u0131 benzerlikler olsa da, bunlar\u0131n istismar y\u00f6ntemleri, hedefleri ve sonu\u00e7lar\u0131 \u00f6nemli \u00f6l\u00e7\u00fcde farkl\u0131l\u0131k g\u00f6stermektedir.<\/p>\n

            Format String Attack ile ilgili perspektifler ve gelecek teknolojiler<\/h2>\n

            Yaz\u0131l\u0131m geli\u015ftirme uygulamalar\u0131 geli\u015ftik\u00e7e geli\u015ftiriciler, bi\u00e7im dizesi sald\u0131r\u0131lar\u0131 gibi g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131n daha fazla fark\u0131na varmaya ba\u015fl\u0131yor. G\u00fcvenli kodlama standartlar\u0131n\u0131n, otomatik kod analiz ara\u00e7lar\u0131n\u0131n ve d\u00fczenli g\u00fcvenlik denetimlerinin kullan\u0131ma sunulmas\u0131yla bu t\u00fcr g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131n say\u0131s\u0131n\u0131n zamanla azalmas\u0131 bekleniyor.<\/p>\n

            Ek olarak, Rust gibi yerle\u015fik bellek g\u00fcvenli\u011fi \u00f6zelliklerine sahip programlama dillerinin geli\u015ftirilmesi, format dizisi sald\u0131r\u0131lar\u0131na kar\u015f\u0131 ekstra bir koruma katman\u0131 sa\u011flayabilir.<\/p>\n

            Proxy sunucular\u0131 nas\u0131l kullan\u0131labilir veya Format String Attack ile nas\u0131l ili\u015fkilendirilebilir?<\/h2>\n

            OneProxy taraf\u0131ndan sa\u011flananlar gibi proxy sunucular\u0131, format dizesi sald\u0131r\u0131lar\u0131n\u0131 azaltmada rol oynayabilir. Proxy sunucular\u0131, istemciler ve hedef sunucular aras\u0131nda arac\u0131 g\u00f6revi g\u00f6rerek gelen istekleri denetlemelerine ve filtrelemelerine olanak tan\u0131r. Proxy sunucu d\u00fczeyinde g\u00fcvenlik \u00f6nlemlerinin uygulanmas\u0131yla olas\u0131 format dizisi sald\u0131r\u0131lar\u0131, hedef sunucuya ula\u015fmadan \u00f6nce yakalan\u0131p engellenebilir.<\/p>\n

            Proxy sunucular\u0131 \u015fu \u015fekilde yap\u0131land\u0131r\u0131labilir:<\/p>\n

              \n
            1. Kullan\u0131c\u0131 Giri\u015fini Filtrele<\/strong>: Proxy sunucular\u0131, kullan\u0131c\u0131 giri\u015fini hedef sunucuya iletmeden \u00f6nce do\u011frulayabilir, b\u00f6ylece k\u00f6t\u00fc ama\u00e7l\u0131 bi\u00e7im dizelerinin savunmas\u0131z uygulamalara ula\u015fmas\u0131 \u00f6nlenebilir.<\/li>\n
            2. Web Uygulamas\u0131 G\u00fcvenlik Duvarlar\u0131<\/strong>: Geli\u015fmi\u015f proxy sunucular\u0131, format dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131na kar\u015f\u0131 korumay\u0131 da i\u00e7eren Web Uygulamas\u0131 G\u00fcvenlik Duvar\u0131 (WAF) i\u015flevselli\u011fini i\u00e7erebilir.<\/li>\n
            3. G\u00fcnl\u00fc\u011fe Kaydetme ve \u0130zleme<\/strong>: Proxy sunucular\u0131, gelen istekleri g\u00fcnl\u00fc\u011fe kaydedebilir ve izleyebilir, b\u00f6ylece potansiyel format dizesi sald\u0131r\u0131 giri\u015fimlerinin tespit edilmesine ve analiz edilmesine yard\u0131mc\u0131 olur.<\/li>\n<\/ol>\n

              \u0130lgili Ba\u011flant\u0131lar<\/h2>\n

              Bi\u00e7im dizesi sald\u0131r\u0131lar\u0131 hakk\u0131nda daha fazla bilgi i\u00e7in a\u015fa\u011f\u0131daki kaynaklar\u0131 incelemeyi d\u00fc\u015f\u00fcn\u00fcn:<\/p>\n

                \n
              1. Format Dizesindeki G\u00fcvenlik A\u00e7\u0131klar\u0131ndan Yararlanma<\/a> \u2013 Mitja Kolsek ve Kostya Kortchinsky'nin OWASP AppSec DC 2006'daki sunumu.<\/li>\n
              2. Format String Hatas\u0131 \u2013 \u0130lk Bak\u0131\u015f<\/a> \u2013 Aleph One'\u0131n format dizesindeki g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 derinlemesine ara\u015ft\u0131ran bir makalesi.<\/li>\n
              3. OWASP \u0130lk On<\/a> \u2013 OWASP'\u0131n format dizesi g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 da i\u00e7eren ilk on web uygulamas\u0131 g\u00fcvenlik riskleri listesi.<\/li>\n<\/ol>\n

                Sonu\u00e7 olarak, format dizesi sald\u0131r\u0131lar\u0131 yaz\u0131l\u0131m sistemleri i\u00e7in \u00f6nemli riskler olu\u015fturur, ancak geli\u015ftiriciler g\u00fcvenli kodlama uygulamalar\u0131n\u0131 benimseyerek ve proxy sunucular\u0131n yeteneklerinden yararlanarak bu tehditlere kar\u015f\u0131 savunma yapabilir ve uygulamalar\u0131n\u0131n ve verilerinin b\u00fct\u00fcnl\u00fc\u011f\u00fcn\u00fc ve g\u00fcvenli\u011fini sa\u011flayabilirler.<\/p>","protected":false},"featured_media":497608,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-477282","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about Format String Attack: Understanding the Vulnerability Exploited by Hackers<\/mark>","faq_items":[{"question":"What is a Format String Attack?","answer":"A Format String Attack is a type of security vulnerability that occurs in computer programming. It allows attackers to exploit the way a program handles formatted input\/output functions, potentially leading to unauthorized access, data leaks, or even code execution on the target system."},{"question":"How did Format String Attacks originate?","answer":"The concept of Format String Attacks was first highlighted in a 2000 paper titled \"Exploiting Format String Vulnerabilities\" by Kostya Kortchinsky. Since then, these attacks have been a significant concern in software development due to their potential to compromise system integrity and confidentiality."},{"question":"How does a Format String Attack work?","answer":"In a Format String Attack, the attacker manipulates the format string parameter in formatted input\/output functions, such as printf()<\/code> and sprintf()<\/code>. By controlling the format string, the attacker can read sensitive data, write to memory addresses, or even execute arbitrary code by exploiting certain format specifiers."},{"question":"What are the key features of a Format String Attack?","answer":"The key features of a Format String Attack include the attacker's ability to control the format string, exploit stack-based memory access, and manipulate memory contents through format specifiers."},{"question":"What types of Format String Attacks exist?","answer":"Format String Attacks can be classified into two main types:\r\n

                  \r\n \t
                1. Reading Attacks: Exploiting format specifiers to read sensitive data from the program's memory.<\/li>\r\n \t
                2. Writing Attacks: Exploiting format specifiers to write data to specific memory addresses, enabling the modification of variables or function pointers.<\/li>\r\n<\/ol>"},{"question":"How can Format String Attacks be prevented?","answer":"To prevent Format String Attacks, developers should:\r\n