{"id":102952,"date":"2022-01-12T21:36:50","date_gmt":"2022-01-12T19:36:50","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0"},"modified":"2022-01-12T21:36:50","modified_gmt":"2022-01-12T19:36:50","slug":"%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/news\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0","title":{"rendered":"O vulnerabilitate \u00een subsistemul eBPF, care permite executarea codului la nivelul nucleei Linux","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\u00cen subsistemul eBPF, care permite rularea handler-elor \u00een cadrul nucleului Linux \u00eentr-o ma\u0219in\u0103 virtual\u0103 special\u0103 cu JIT, a fost descoperit\u0103 o vulnerabilitate (CVE-2021-4204) care le permite utilizatorilor locali f\u0103r\u0103 privilegii s\u0103 ob\u021bin\u0103 cre\u0219terea privilegiilor \u0219i s\u0103 execute codul lor la nivelul nucleului Linux. Problema apare \u00eencep\u00e2nd cu nucleul Linux 5.8 \u0219i r\u0103m\u00e2ne nerezolvat\u0103 (afecteaz\u0103 de asemenea versiunea 5.16). Starea actualiz\u0103rilor pentru remedierea problemei \u00een distribu\u021bii poate fi urm\u0103rit\u0103 pe aceste pagini: Debian, RHEL, SUSE, Fedora, Ubuntu, Arch. S-a raportat crearea unui exploit func\u021bional, care se preconizeaz\u0103 c\u0103 va fi publicat pe 18 ianuarie (utilizatorii \u0219i dezvoltatorii au primit o s\u0103pt\u0103m\u00e2n\u0103 pentru a remedia vulnerabilitatea). <\/p>\n

Vulnerabilitatea este cauzat\u0103 de verificarea incorect\u0103 a programelor eBPF transmise pentru execu\u021bie. Subsistemul eBPF ofer\u0103 func\u021bii auxiliare, a c\u0103ror corectitudine este verificat\u0103 de un validator specializat. Unele func\u021bii necesit\u0103 transmiterea valorii PTR_TO_MEM ca argument, iar pentru a preveni posibilele dep\u0103\u0219iri de buffer, validatorul trebuie s\u0103 cunoasc\u0103 dimensiunea memoriei asociate argumentului. Pentru func\u021biile bpf_ringbuf_submit \u0219i bpf_ringbuf_discard, informa\u021biile despre dimensiunea memoriei transmise nu au fost comunicate validatorului, ceea ce ar putea fi folosit pentru a suprascrie regiuni de memorie \u00een afara bufferului \u00een timpul execut\u0103rii unui cod eBPF special conceput. <\/p>\n

Pentru a efectua un atac, utilizatorul trebuie s\u0103 aib\u0103 posibilitatea de a \u00eenc\u0103rca programul s\u0103u BPF, iar multe distribu\u021bii recente de Linux blocheaz\u0103 acest lucru \u00een mod implicit (inclusiv accesul neprivilegiat la eBPF este acum interzis implicit \u00een kernel, \u00eencep\u00e2nd cu versiunea 5.16). De exemplu, vulnerabilitatea poate fi exploatat\u0103 \u00een configura\u021bia implicit\u0103 din Ubuntu 20.04 LTS, dar \u00een medii precum Ubuntu 22.04-dev, Debian 11, openSUSE 15.3, RHEL 8.5, SUSE 15-SP4 \u0219i Fedora 33 apare doar dac\u0103 administratorul a setat parametrul kernel.unprivileged_bpf_disabled la valoarea 0. Ca o solu\u021bie workaround pentru blocarea vulnerabilit\u0103\u021bii, se poate interzice executarea programelor BPF de c\u0103tre utilizatorii neprivilegiati cu comanda \"sysctl -w kernel.unprivileged_bpf_disabled=1\".
\n
Sursa: opennet.ro<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 eBPF, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0437\u0430\u043f\u0443\u0441\u043a\u0430\u0442\u044c \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a\u0438 \u0432\u043d\u0443\u0442\u0440\u0438 \u044f\u0434\u0440\u0430 Linux \u0432 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0439 \u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u043e\u0439 \u043c\u0430\u0448\u0438\u043d\u0435 \u0441 JIT, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-4204), \u0434\u0430\u044e\u0449\u0430\u044f \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043d\u0435\u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u043f\u043e\u0432\u044b\u0448\u0435\u043d\u0438\u044f \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0439 \u0438 \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u0441\u0432\u043e\u0435\u0433\u043e \u043a\u043e\u0434\u0430 \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 \u044f\u0434\u0440\u0430 Linux. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u043d\u0430\u0447\u0438\u043d\u0430\u044f \u0441 \u044f\u0434\u0440\u0430 Linux 5.8 \u0438 \u043f\u043e\u043a\u0430 \u043e\u0441\u0442\u0430\u0451\u0442\u0441\u044f \u043d\u0435\u0438\u0441\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u043d\u043e\u0439 (\u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u0435\u0442 \u0432 \u0442\u043e\u043c \u0447\u0438\u0441\u043b\u0435 \u0432\u044b\u043f\u0443\u0441\u043a 5.16). \u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0444\u043e\u0440\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0439 \u0441 […]<\/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-102952","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\udd47Vulnerabilitate \u00een subsistemul eBPF, care permite executarea codului la nivelul nucleului Linux | ProHoster","description":"\u00cen subsistemul eBPF, care permite rularea handler-elor \u00een nucleul Linux \u00eentr-o ma\u0219in\u0103 virtual\u0103 special\u0103 cu JIT, a fost descoperit\u0103 o vulnerabilitate (CVE-2021-4204), care le ofer\u0103 utilizatorilor locali f\u0103r\u0103 privilegii posibilitatea de a exploata aceasta.","canonical_url":"https:\/\/prohoster.info\/ro\/blog\/news\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"ro_RO","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 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