{"id":101245,"date":"2021-09-10T22:22:37","date_gmt":"2021-09-10T20:22:37","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-ghostscript-ekspluatiruemaya-cherez-imagemagick"},"modified":"2021-09-10T22:22:37","modified_gmt":"2021-09-10T20:22:37","slug":"uyazvimost-v-ghostscript-ekspluatiruemaya-cherez-imagemagick","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/news\/uyazvimost-v-ghostscript-ekspluatiruemaya-cherez-imagemagick","title":{"rendered":"Ghostscript s\u00e9r\u00fcl\u00e9kenys\u00e9ge, amelyet az ImageMagick-on kereszt\u00fcl haszn\u00e1lnak ki","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

A Ghostscript, az PostScript \u00e9s PDF form\u00e1tum\u00fa dokumentumok feldolgoz\u00e1s\u00e1ra, \u00e1talak\u00edt\u00e1s\u00e1ra \u00e9s gener\u00e1l\u00e1s\u00e1ra szolg\u00e1l\u00f3 eszk\u00f6zk\u00e9szlet, kritikus sebezhet\u0151s\u00e9get (CVE-2021-3781) t\u00e1rt fel, amely lehet\u0151v\u00e9 teszi tetsz\u0151leges k\u00f3d v\u00e9grehajt\u00e1s\u00e1t speci\u00e1lisan megform\u00e1zott f\u00e1jlok feldolgoz\u00e1sakor. E probl\u00e9m\u00e1ra Emil Lerner h\u00edvta fel a figyelmet, aki a sebezhet\u0151s\u00e9gr\u0151l augusztus 25-\u00e9n a Szentp\u00e9terv\u00e1ron megrendezett ZeroNights X konferenci\u00e1n besz\u00e9lt (az el\u0151ad\u00e1sban elmondta, hogyan haszn\u00e1lta a sebezhet\u0151s\u00e9get bug bounty program keret\u00e9ben, hogy d\u00edjat nyerjen t\u00e1mad\u00e1sok bemutat\u00e1s\u00e1\u00e9rt az AirBNB, Dropbox \u00e9s Yandex.Neh\u00e9zs\u00e9gek szolg\u00e1ltat\u00e1sain).<\/p> <\/p>\n

Szeptember 5-\u00e9n nyilv\u00e1nos hozz\u00e1f\u00e9r\u00e9s\u0171v\u00e9 v\u00e1lt egy m\u0171k\u00f6d\u0151 exploit, amely lehet\u0151v\u00e9 teszi az Ubuntu 20.04 rendszerek t\u00e1mad\u00e1s\u00e1t az\u00e1ltal, hogy egy web-szkripthez, amely a php-imagemagick csomagot haszn\u00e1lja, egy speci\u00e1lisan megform\u00e1zott dokumentumot adunk \u00e1t k\u00e9pk\u00e9nt. Az el\u0151zetes inform\u00e1ci\u00f3k szerint ez az exploit m\u00e1r m\u00e1rcius \u00f3ta forgalomban volt. A GhostScript 9.50 rendszerekkel val\u00f3 t\u00e1mad\u00e1sr\u00f3l \u00e9rkeztek jelent\u00e9sek, de kider\u00fclt, hogy a sebezhet\u0151s\u00e9g minden subsequent GhostScript verzi\u00f3ban, bele\u00e9rtve a fejleszt\u00e9s alatt \u00e1ll\u00f3 9.55-\u00f6t is, megjelenik a Git-b\u0151l. <\/p>\n

A jav\u00edt\u00e1st szeptember 8-\u00e1n javasolt\u00e1k, \u00e9s azt k\u00f6vet\u0151en, hogy \u00e1ttekintett\u00e9k, szeptember 9-\u00e9n elfogadt\u00e1k a GhostScript t\u00e1rol\u00f3ba. Sz\u00e1mos disztrib\u00faci\u00f3ban a probl\u00e9ma m\u00e9g mindig nem ker\u00fclt jav\u00edt\u00e1sra (a friss\u00edt\u00e9sek kiad\u00e1s\u00e1nak \u00e1llapot\u00e1t a Debian, Ubuntu, Fedora, SUSE, RHEL, Arch Linux, FreeBSD, NetBSD oldalain ellen\u0151rizheti). A GhostScript kiad\u00e1s\u00e1t, amely orvosolja a sebezhet\u0151s\u00e9get, a h\u00f3nap v\u00e9g\u00e9ig tervezik megjelentetni. <\/p>\n

A probl\u00e9ma a %-dSAFER-izol\u00e1ci\u00f3s m\u00f3d kiker\u00fcl\u00e9s\u00e9nek lehet\u0151s\u00e9ge miatt mer\u00fclt fel, amely a Postscript-eszk\u00f6z «%pipe%» param\u00e9tereinek el\u00e9gtelen ellen\u0151rz\u00e9s\u00e9b\u0151l fakadt, lehet\u0151v\u00e9 t\u00e9ve tetsz\u0151leges shell-parancsok v\u00e9grehajt\u00e1s\u00e1t. P\u00e9ld\u00e1ul az id seg\u00e9dprogram elind\u00edt\u00e1s\u00e1hoz a dokumentumban elegend\u0151 megadni a «(%pipe%\/tmp\/&id)(w)file» vagy a «(%pipe%\/tmp\/;id)(r)file» sort. <\/p>\n

Eml\u00e9keztet\u00fcnk, hogy a Ghostscript sebezhet\u0151s\u00e9gei fokozott vesz\u00e9lyt jelentenek, mivel ezt a csomagot sok n\u00e9pszer\u0171 alkalmaz\u00e1s haszn\u00e1lja PostScript \u00e9s PDF form\u00e1tumok feldolgoz\u00e1s\u00e1ra. P\u00e9ld\u00e1ul a Ghostscript h\u00edv\u00f3dik meg az asztalon t\u00f6rt\u00e9n\u0151 miniat\u00far\u00e1k l\u00e9trehoz\u00e1sakor, h\u00e1tt\u00e9rben zajl\u00f3 adatindexel\u00e9s sor\u00e1n \u00e9s k\u00e9pek \u00e1talak\u00edt\u00e1sakor. A t\u00e1mad\u00e1s siker\u00e9hez sok esetben elegend\u0151 egyszer\u0171en felt\u00f6lteni egy sebezhet\u0151s\u00e9get kihaszn\u00e1l\u00f3 f\u00e1jlt, vagy megtekinteni egy mapp\u00e1t egy f\u00e1jlkezel\u0151ben, amely t\u00e1mogatja a dokumentumok miniat\u00far\u00e1inak megjelen\u00edt\u00e9s\u00e9t, p\u00e9ld\u00e1ul a Nautilusban. <\/p>\n

A Ghostscript sebezhet\u0151s\u00e9geit az ImageMagick \u00e9s a GraphicsMagick csomagokon alapul\u00f3 k\u00e9pkezel\u0151k is kihaszn\u00e1lhatj\u00e1k, ha JPEG vagy PNG f\u00e1jlt adunk \u00e1t nekik, amelyben a k\u00e9p helyett PostScript k\u00f3d tal\u00e1lhat\u00f3 (ez a f\u00e1jl a Ghostscript-en kereszt\u00fcl lesz feldolgozva, mivel a MIME-t\u00edpus a tartalom alapj\u00e1n, \u00e9s nem a kiterjeszt\u00e9sre t\u00e1maszkodva ismerhet\u0151 fel).
\n
Forr\u00e1s: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 Ghostscript, \u043d\u0430\u0431\u043e\u0440\u0435 \u0438\u043d\u0441\u0442\u0440\u0443\u043c\u0435\u043d\u0442\u043e\u0432 \u0434\u043b\u044f \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0438, \u043f\u0440\u0435\u043e\u0431\u0440\u0430\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u0438 \u0433\u0435\u043d\u0435\u0440\u0430\u0446\u0438\u0438 \u0434\u043e\u043a\u0443\u043c\u0435\u043d\u0442\u043e\u0432 \u0432 \u0444\u043e\u0440\u043c\u0430\u0442\u0430\u0445 PostScript \u0438 PDF, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u043a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-3781), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u043b\u044c\u043d\u044b\u0439 \u043a\u043e\u0434 \u043f\u0440\u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u043e\u0433\u043e \u0444\u0430\u0439\u043b\u0430. \u0418\u0437\u043d\u0430\u0447\u0430\u043b\u044c\u043d\u043e \u043d\u0430 \u043d\u0430\u043b\u0438\u0447\u0438\u0435 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u044b \u043e\u0431\u0440\u0430\u0442\u0438\u043b \u0432\u043d\u0438\u043c\u0430\u043d\u0438\u0435 \u042d\u043c\u0438\u043b\u044c \u041b\u0435\u0440\u043d\u0435\u0440, \u043a\u043e\u0442\u043e\u0440\u044b\u0439 \u0440\u0430\u0441\u0441\u043a\u0430\u0437\u0430\u043b \u043e\u0431 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 25 \u0430\u0432\u0433\u0443\u0441\u0442\u0430 \u043d\u0430 \u043f\u0440\u043e\u0448\u0435\u0434\u0448\u0435\u0439 \u0432 \u0421\u0430\u043d\u043a\u0442-\u041f\u0435\u0442\u0435\u0440\u0431\u0443\u0440\u0433\u0435 \u043a\u043e\u043d\u0444\u0435\u0440\u0435\u043d\u0446\u0438\u0438 ZeroNights X (\u0432 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