{"id":90288,"date":"2020-07-30T13:42:19","date_gmt":"2020-07-30T11:42:19","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/kriticheskaya-uyazvimost-v-zagruzchike-grub2-pozvolyayushhaya-obojti-uefi-secure-boot"},"modified":"2020-07-30T13:42:19","modified_gmt":"2020-07-30T11:42:19","slug":"kriticheskaya-uyazvimost-v-zagruzchike-grub2-pozvolyayushhaya-obojti-uefi-secure-boot","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sq\/blog\/novosti-interneta\/kriticheskaya-uyazvimost-v-zagruzchike-grub2-pozvolyayushhaya-obojti-uefi-secure-boot","title":{"rendered":"Vulnerabilitet kritik n\u00eb ngarkuesin GRUB2 q\u00eb lejon kalimin e UEFI Secure Boot","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

N\u00eb bootloader-in GRUB2 identifikuar<\/a><\/noindex> 8 dob\u00ebsi. M\u00eb e rrezikshmja problemi<\/a><\/noindex> (CVE-2020-10713<\/a><\/noindex>), e cila ka emrin kodor BootHole, ofron mund\u00ebsin\u00eb<\/a><\/noindex> p\u00ebr t\u00eb anashkaluar mekanizmin UEFI Secure Boot dhe p\u00ebr t\u00eb arritur instalimin e softuerit t\u00eb d\u00ebmsh\u00ebm t\u00eb pav\u00ebrtetuar. Karakteristik\u00eb e k\u00ebsaj dob\u00ebsie \u00ebsht\u00eb se p\u00ebr ta eliminuar at\u00eb nuk mjafton t\u00eb p\u00ebrdit\u00ebsohet GRUB2, pasi sulmuesi mund t\u00eb p\u00ebrdor\u00eb nj\u00eb pajisje bootuese me nj\u00eb version t\u00eb vjet\u00ebr t\u00eb dob\u00ebsis\u00eb, t\u00eb cilin e ka n\u00ebnshkruar nj\u00eb n\u00ebnshkrim digjital. Sulmuesi mund t\u00eb komprometoj\u00eb procesin e verifikimit jo vet\u00ebm t\u00eb Linux-it, por edhe t\u00eb sistemeve t\u00eb tjera operative, duke p\u00ebrfshir\u00eb Windows<\/a><\/noindex>. <\/p>\n

Problemi zgjidhet vet\u00ebm p\u00ebrmes p\u00ebrdit\u00ebsimit n\u00eb sistem t\u00eb list\u00ebs s\u00eb certifikatat e revokuara<\/a><\/noindex> (dbx, Lista e Revokimeve UEFI), por n\u00eb k\u00ebt\u00eb rast do t\u00eb humbim mund\u00ebsin\u00eb e p\u00ebrdorimit t\u00eb pajisjeve instalues t\u00eb vjetra me Linux. Disa prodhues pajisjesh tashm\u00eb kan\u00eb p\u00ebrfshir\u00eb n\u00eb firmware-in e tyre list\u00ebn e p\u00ebrdit\u00ebsuar t\u00eb certifikatave t\u00eb revokuara, n\u00eb k\u00ebto sisteme n\u00eb modin UEFI Secure Boot do t\u00eb jet\u00eb e mundur t\u00eb ngarkohet vet\u00ebm versionet e p\u00ebrdit\u00ebsuara t\u00eb distribucioneve Linux. <\/p>\n

P\u00ebr t\u00eb eliminuar dob\u00ebsin\u00eb n\u00eb shp\u00ebrndarjet, do t\u00eb jet\u00eb gjithashtu e nevojshme t\u00eb p\u00ebrdit\u00ebsohen instaluesit, bootloader\u00ebt, paketat e b\u00ebrtham\u00ebs, firmuerit fwupd dhe shtresa shim, duke krijuar n\u00ebnshkrime t\u00eb reja digjitale p\u00ebr to. P\u00ebrdoruesit do t\u00eb duhet t\u00eb p\u00ebrdit\u00ebsojn\u00eb imazhet e instalimit dhe mediatosh t\u00eb tjera t\u00eb ngarkes\u00ebs, si dhe t\u00eb shkarkojn\u00eb list\u00ebn e certifikatave t\u00eb t\u00ebrhequra (dbx) n\u00eb firmware UEFI. Deri n\u00eb p\u00ebrdit\u00ebsimin e dbx n\u00eb UEFI, sistemi mbetet i dobish\u00ebm pavar\u00ebsisht nga instalimi i p\u00ebrdit\u00ebsimeve n\u00eb OS. <\/p>\n

Vulnerabiliteti shkaktua<\/a><\/noindex> teknik\u00ebs s\u00eb tejkalimit t\u00eb buffers, e cila mund t\u00eb shfryt\u00ebzohet p\u00ebr t\u00eb ekzekutuar kod t\u00eb rast\u00ebsish\u00ebm gjat\u00eb procesit t\u00eb ngarkes\u00ebs.
\nDob\u00ebsia shfaqet gjat\u00eb analiz\u00ebs s\u00eb p\u00ebrmbajtjes s\u00eb skedarit t\u00eb konfigurimit grub.cfg, i cili zakonisht ndodhet n\u00eb seksionin ESP (EFI System Partition) dhe mund t\u00eb redaktohet nga nj\u00eb sulmues me t\u00eb drejta administratori, pa shkaktuar renat\u00ebn e skedar\u00ebve ekzekutiv\u00eb t\u00eb n\u00ebnshkruar shim dhe GRUB2. P\u00ebr shkak t\u00eb gabimit<\/a><\/noindex> n kodin e parserit t\u00eb konfigurimit, menaxhuesi i gabimeve fatale YY_FATAL_ERROR vet\u00ebm nxiste nj\u00eb paralajm\u00ebrim, por nuk e ndalte programin. Rreziku i k\u00ebsaj dob\u00ebsie zvog\u00eblohet nga nevoja p\u00ebr t\u00eb pasur akses t\u00eb privilegjuar n\u00eb sistem, megjithat\u00eb, problemi mund t\u00eb jet\u00eb i k\u00ebrkuar p\u00ebr t\u00eb implementuar rootkit t\u00eb fshehur n\u00ebse ka qasje fizike n\u00eb pajisjen (n\u00ebse \u00ebsht\u00eb e mundur t\u00eb ngarkohet nga nj\u00eb pajisje e vetme).<\/p>\n

N\u00eb shumic\u00ebn e distribucioneve Linux, p\u00ebr ngarkim t\u00eb verifikuar p\u00ebrdoret nj\u00eb shtres\u00eb shim<\/a><\/noindex>, e cila \u00ebsht\u00eb e n\u00ebnshkruar digjitalisht nga Microsoft. Kjo shtres\u00eb verifikon GRUB2 me certifikat\u00ebn e saj, duke i lejuar zhvilluesve t\u00eb distribucioneve t\u00eb mos e n\u00ebnshkruajn\u00eb \u00e7do p\u00ebrdit\u00ebsim t\u00eb b\u00ebrtham\u00ebs dhe GRUB te Microsoft. Dob\u00ebsia lejon, p\u00ebrmes ndryshimit t\u00eb p\u00ebrmbajtjes s\u00eb grub.cfg, arritjen e ekzekutimit t\u00eb kodit t\u00eb vet n\u00eb etap\u00ebn pas verifikimit t\u00eb suksessh\u00ebm t\u00eb shim, por p\u00ebrpara ngarkimit t\u00eb sistemit operativ, duke u infiltruese n\u00eb zinxhirin e besueshm\u00ebris\u00eb n\u00eb modalitetin Aktiv i Secure Boot dhe duke marr\u00eb kontroll t\u00eb plot\u00eb mbi procesin e ngarkimit t\u00eb m\u00ebtejsh\u00ebm, p\u00ebrfshir\u00eb ngarkimin e nj\u00eb sistemi tjet\u00ebr operativ, modifikimin e komponenteve t\u00eb sistemit operativ dhe kalimin mbi mbrojtjen. Lockdown<\/a><\/noindex>. <\/p>\n

\"Vulnerabilitet<\/a><\/noindex><\/center><\/p>\n

Vulnerabilitete t\u00eb tjera n\u00eb GRUB2:<\/p>\n