{"id":110745,"date":"2023-10-11T21:10:17","date_gmt":"2023-10-11T19:10:17","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/perepolnenie-bufera-v-curl-i-libcurl-proyavlyayushheesya-pri-obrashhenii-cherez-socks5-proksi"},"modified":"2023-10-11T21:10:17","modified_gmt":"2023-10-11T19:10:17","slug":"perepolnenie-bufera-v-curl-i-libcurl-proyavlyayushheesya-pri-obrashhenii-cherez-socks5-proksi","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hr\/blog\/news\/perepolnenie-bufera-v-curl-i-libcurl-proyavlyayushheesya-pri-obrashhenii-cherez-socks5-proksi","title":{"rendered":"Prelivanje bafera u curl i libcurl, koje se manifestira prilikom pristupa preko SOCKS5 proxyja","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

U alatu za prijenos i slanje podataka putem mre\u017ee curl i razvoju paralelne biblioteke libcurl otkrivena je ranjivost (CVE-2023-38545) koja mo\u017ee dovesti do preljeva bafer i potencijalno do izvr\u0161enja koda napada\u010da na strani klijenta prilikom kori\u0161tenja alata curl ili aplikacije koja koristi libcurl za pristup HTTPS serveru pod kontrolom napada\u010da. Problem se manifestira samo u slu\u010daju kada je u curl-u omogu\u0107en pristup putem SOCKS5 proxy-a. Prilikom izravnog pristupa bez proxy-a ranjivost se ne manifestira. Ranjivost je otklonjena u izdanju curl 8.4.0. Istra\u017eiva\u010d sigurnosti koji je otkrio gre\u0161ku dobio je nagradu u iznosu od 4660 dolara kroz inicijativu Internet Bug Bounty na Hackerone. <\/p>\n

Ranjivost je uzrokovana gre\u0161kom u kodu koji rje\u0161ava ime doma\u0107ina prije pristupa SOCKS5 proxy-u. Kada je ime doma\u0107ina duga\u010dko do 256 znakova, curl odmah proslje\u0111uje ime u SOCKS5 proxy za rje\u0161avanje s njegove strane, a ako je ime du\u017ee od 255 znakova, prebacuje se na lokalni resolver i proslje\u0111uje u SOCKS5 ve\u0107 odre\u0111enu adresu. Zbog gre\u0161ke u kodu, zastavica koja ozna\u010dava potrebu za lokalnim rje\u0161avanjem mogla je biti postavljena na pogre\u0161nu vrijednost tijekom sporog pregovaranja veze putem SOCKS5, \u0161to je dovelo do upisa dugog imena doma\u0107ina u bafer dodijeljen za pohranu IP adrese<\/a> ili imena koje ne prelazi 255 znakova. <\/p>\n

Vlasnik web stranice, na koju curl \u0161alje zahtjev putem SOCKS5 proxyja, mo\u017ee inicirati preklapanje bafera na strani klijenta, vra\u0107aju\u0107i u odgovoru kod preusmjeravanja zahtjeva (HTTP 30x) i postavljaju\u0107i u zaglavlju «Location:» URL s nazivom doma\u0107ina, \u010dija veli\u010dina se kre\u0107e od 16 do 64 KB (vrijednost 16 KB je uzrokovana minimalnom veli\u010dinom potrebnom za preklapanje dodijeljenog bafera, dok se vrijednost 65 KB odnosi na maksimalno dopu\u0161tenu duljinu naziva doma\u0107ina u URL-u). Ako su u postavkama libcurl omogu\u0107ena preusmjeravanja zahtjeva i kori\u0161teni SOCKS5 proxy je dovoljno spor, tada \u0107e dugi naziv doma\u0107ina biti zapisan u mali bafer, o\u010digledno manji od potrebnog. <\/p>\n

Ranljivost se prvenstveno odnosi na aplikacije temeljenim na libcurl i o\u010dituje se u alatu curl samo kada se koristi opcija «—limit-rate» s vrijedno\u0161\u0107u manjom od 65541 — u libcurl po defaultu se dodjeljuje bafer veli\u010dine 16 KB, dok se u alatu curl — 100 KB, ali ova veli\u010dina varira ovisno o vrijednosti parametra «—limit-rate». <\/p>\n

Daniel Stenberg, autor projekta, spomenuo je da je ranjivost ostala neprimije\u0107ena tijekom 1315 dana. Tako\u0111er je re\u010deno da bi se 41% ranjivosti otkrivenih u curl-u vjerojatno moglo izbje\u0107i da je curl napisan na jeziku koji osigurava sigurnu obradu memorije, no prepisivanje curl-a na drugi jezik nije planirano u bliskoj budu\u0107nosti. Kao mjere za pove\u0107anje sigurnosti kodne baze predla\u017ee se pro\u0161irenje alata za testiranje koda i aktivnije kori\u0161tenje ovisnosti napisane na programskim jezicima koji osiguravaju sigurnu obradu memorije. Tako\u0111er se razmatra mogu\u0107nost postepene zamjene dijelova curl-a s varijantama napisanima na sigurnim jezicima, poput eksperimentalnog HTTP-bazena Hyper, implementiranog na jeziku Rust.
\n
Izvor: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u0443\u0442\u0438\u043b\u0438\u0442\u0435 \u0434\u043b\u044f \u043f\u043e\u043b\u0443\u0447\u0435\u043d\u0438\u044f \u0438 \u043e\u0442\u043f\u0440\u0430\u0432\u043a\u0438 \u0434\u0430\u043d\u043d\u044b\u0445 \u043f\u043e \u0441\u0435\u0442\u0438 curl \u0438 \u0440\u0430\u0437\u0432\u0438\u0432\u0430\u044e\u0449\u0435\u0439\u0441\u044f \u043f\u0430\u0440\u0430\u043b\u043b\u0435\u043b\u044c\u043d\u043e \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0435 libcurl \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-38545), \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043c\u043e\u0436\u0435\u0442 \u043f\u0440\u0438\u0432\u0435\u0441\u0442\u0438 \u043a \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u0431\u0443\u0444\u0435\u0440\u0430 \u0438 \u043f\u043e\u0442\u0435\u043d\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043a \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e 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\u0432\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044f \u0432 curl […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-110745","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Prelivanje bafera u curl i libcurl, koje se o\u010dituje prilikom pristupa preko SOCKS5-proksija | ProHoster","description":"U alatu za primanje i slanje podataka putem mre\u017ee curl i paralelno razvijanoj biblioteci libcurl otkrivena je ranjivost (CVE-2023-38545) koja mo\u017ee dovesti do prelivanja bafera i potencijalno do izvr\u0161avanja.","canonical_url":"https:\/\/prohoster.info\/hr\/blog\/news\/perepolnenie-bufera-v-curl-i-libcurl-proyavlyayushheesya-pri-obrashhenii-cherez-socks5-proksi","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"hr_HR","og:site_name":"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 \u0445\u043e\u0441\u0442\u0438\u043d\u0433 \u0434\u043b\u044f \u0441\u0430\u0439\u0442\u043e\u0432 \u0441 \u0437\u0430\u0449\u0438\u0442\u043e\u0439 \u043e\u0442 DDoS, VPS VDS \u0441\u0435\u0440\u0432\u0435\u0440\u044b","og:type":"article","og:title":"\ud83e\udd47\u041f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435 \u0431\u0443\u0444\u0435\u0440\u0430 \u0432 curl \u0438 libcurl, \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u044e\u0449\u0435\u0435\u0441\u044f \u043f\u0440\u0438 \u043e\u0431\u0440\u0430\u0449\u0435\u043d\u0438\u0438 \u0447\u0435\u0440\u0435\u0437 SOCKS5-\u043f\u0440\u043e\u043a\u0441\u0438 | ProHoster","og:description":"\u0412 \u0443\u0442\u0438\u043b\u0438\u0442\u0435 \u0434\u043b\u044f \u043f\u043e\u043b\u0443\u0447\u0435\u043d\u0438\u044f \u0438 \u043e\u0442\u043f\u0440\u0430\u0432\u043a\u0438 \u0434\u0430\u043d\u043d\u044b\u0445 \u043f\u043e \u0441\u0435\u0442\u0438 curl \u0438 \u0440\u0430\u0437\u0432\u0438\u0432\u0430\u044e\u0449\u0435\u0439\u0441\u044f \u043f\u0430\u0440\u0430\u043b\u043b\u0435\u043b\u044c\u043d\u043e \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0435 libcurl \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-38545), \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043c\u043e\u0436\u0435\u0442 \u043f\u0440\u0438\u0432\u0435\u0441\u0442\u0438 \u043a \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u0431\u0443\u0444\u0435\u0440\u0430 \u0438 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