In Netfilter, dem Kernel-Subsystem von Linux, das zur Filterung und Modifikation von Netzwerkpaketen verwendet wird, wurde eine Schwachstelle (CVE-2021-22555) entdeckt, die es einem lokalen Benutzer erm\u00f6glicht, Root-Rechte im System zu erlangen, selbst in einem isolierten Container. Ein funktionsf\u00e4higer Prototyp eines Exploits wurde entwickelt, der die Schutzmechanismen von KASLR, SMAP und SMEP umgeht. Der Forscher, der die Schwachstelle entdeckte, erhielt von Google eine Belohnung in H\u00f6he von 20.000 US-Dollar f\u00fcr die Entdeckung einer Methode zur Umgehung der Isolation von Kubernetes-Containern im kCTF-Cluster. <\/p>\n
Das Problem besteht seit dem Kernel 2.6.19, der vor 15 Jahren ver\u00f6ffentlicht wurde, und wird durch einen Fehler in den Handlers IPT_SO_SET_REPLACE und IP6T_SO_SET_REPLACE verursacht, was zu einem Puffer\u00fcberlauf f\u00fchrt, wenn speziell gestaltete Parameter \u00fcber den Aufruf von setsockopt im Kompatibilit\u00e4tsmodus gesendet werden. Unter normalen Bedingungen kann der Aufruf von compat_setsockopt() nur vom Benutzer root ausgef\u00fchrt werden, aber die f\u00fcr den Angriff erforderlichen Berechtigungen k\u00f6nnen auch von nicht privilegierten Benutzern in Systemen mit aktivierter Unterst\u00fctzung f\u00fcr Benutzer-ID-Namensr\u00e4ume (user namespaces) erlangt werden. <\/p>\n
\u041f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044c \u043c\u043e\u0436\u0435\u0442 \u0441\u043e\u0437\u0434\u0430\u0442\u044c \u043a\u043e\u043d\u0442\u0435\u0439\u043d\u0435\u0440 \u0441 \u043e\u0442\u0434\u0435\u043b\u044c\u043d\u044b\u043c \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u043c root \u0438 \u0438\u0437 \u043d\u0435\u0433\u043e \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c. \u041d\u0430\u043f\u0440\u0438\u043c\u0435\u0440, «user namespaces» \u043f\u043e \u0443\u043c\u043e\u043b\u0447\u0430\u043d\u0438\u044e \u0432\u043a\u043b\u044e\u0447\u0451\u043d \u0432 Ubuntu \u0438 Fedora, \u043d\u043e \u043d\u0435 \u0430\u043a\u0442\u0438\u0432\u0438\u0440\u043e\u0432\u0430\u043d \u0432 Debian \u0438 RHEL. \u041f\u0430\u0442\u0447 \u0441 \u0438\u0441\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u0438\u0435\u043c \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043f\u0440\u0438\u043d\u044f\u0442 \u0432 \u0441\u043e\u0441\u0442\u0430\u0432 \u044f\u0434\u0440\u0430 Linux 13 \u0430\u043f\u0440\u0435\u043b\u044f. \u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f \u043f\u0430\u043a\u0435\u0442\u043e\u0432 \u0443\u0436\u0435 \u0441\u0444\u043e\u0440\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u044b \u043f\u0440\u043e\u0435\u043a\u0442\u0430\u043c\u0438 Debian, Arch Linux \u0438 Fedora. \u0412 Ubuntu, RHEL \u0438 SUSE \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f \u043d\u0430 \u0441\u0442\u0430\u0434\u0438\u0438 \u043f\u043e\u0434\u0433\u043e\u0442\u043e\u0432\u043a\u0438. <\/p>\n
\u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0432\u043e\u0437\u043d\u0438\u043a\u0430\u0435\u0442 \u0432 \u0444\u0443\u043d\u043a\u0446\u0438\u0438 xt_compat_target_from_user() \u0438\u0437-\u0437\u0430 \u043d\u0435\u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u043e\u0433\u043e \u0440\u0430\u0441\u0447\u0451\u0442\u0430 \u0440\u0430\u0437\u043c\u0435\u0440\u0430 \u043f\u0430\u043c\u044f\u0442\u0438 \u043f\u0440\u0438 \u0441\u043e\u0445\u0440\u0430\u043d\u0435\u043d\u0438\u0438 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440 \u044f\u0434\u0440\u0430 \u043f\u043e\u0441\u043b\u0435 \u043f\u0440\u0435\u043e\u0431\u0440\u0430\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u0438\u0437 32- \u0432 64-\u0440\u0430\u0437\u0440\u044f\u0434\u043d\u043e\u0435 \u043f\u0440\u0435\u0434\u0441\u0442\u0430\u0432\u043b\u0435\u043d\u0438\u0435. \u041e\u0448\u0438\u0431\u043a\u0430 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u0437\u0430\u043f\u0438\u0441\u0430\u0442\u044c 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\u0438 \u0438\u0437\u043c\u0435\u043d\u0435\u043d\u0438\u044f \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440 \u0447\u0435\u0440\u0435\u0437 \u043c\u0430\u043d\u0438\u043f\u0443\u043b\u044f\u0446\u0438\u044e \u0441 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u044b\u043c \u0432\u044b\u0437\u043e\u0432\u043e\u043c msgsnd(). \u0412 Netfilter, \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u044f\u0434\u0440\u0430 Linux, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u043c\u043e\u0439 \u0434\u043b\u044f \u0444\u0438\u043b\u044c\u0442\u0440\u0430\u0446\u0438\u0438 \u0438 \u043c\u043e\u0434\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u0441\u0435\u0442\u0435\u0432\u044b\u0445 \u043f\u0430\u043a\u0435\u0442\u043e\u0432, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-22555), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 root \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435, \u0432 \u0442\u043e\u043c \u0447\u0438\u0441\u043b\u0435 \u043d\u0430\u0445\u043e\u0434\u044f\u0441\u044c \u0432 \u0438\u0437\u043e\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c \u043a\u043e\u043d\u0442\u0435\u0439\u043d\u0435\u0440\u0435. \u0414\u043b\u044f \u0442\u0435\u0441\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043f\u043e\u0434\u0433\u043e\u0442\u043e\u0432\u043b\u0435\u043d \u0440\u0430\u0431\u043e\u0447\u0438\u0439 \u043f\u0440\u043e\u0442\u043e\u0442\u0438\u043f \u044d\u043a\u0441\u043f\u043b\u043e\u0438\u0442\u0430, \u043e\u0431\u0445\u043e\u0434\u044f\u0449\u0438\u0439 \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u044b \u0437\u0430\u0449\u0438\u0442\u044b KASLR, SMAP \u0438 SMEP. \u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c, \u0432\u044b\u044f\u0432\u0438\u0432\u0448\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c, \u043f\u043e\u043b\u0443\u0447\u0438\u043b \u043e\u0442 Google \u0432\u043e\u0437\u043d\u0430\u0433\u0440\u0430\u0436\u0434\u0435\u043d\u0438\u0435, \u0440\u0430\u0437\u043c\u0435\u0440\u043e\u043c 20 \u0442\u044b\u0441\u044f\u0447 \u0434\u043e\u043b\u043b\u0430\u0440\u043e\u0432, \u0437\u0430 […]<\/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-100767","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\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\udd47Schwachstelle im Linux-Kernel-Netfilter | ProHoster","description":"Im Netfilter, dem Teil des Linux-Kernels zur Filterung und Modifizierung von Netzwerkpaketen, wurde eine Schwachstelle (CVE-2021-22555) entdeckt, die es einem lokalen Benutzer erm\u00f6glicht, Root-Rechte im System zu erlangen, 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Quelle: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"