A Qualys c\u00e9g felfedezett egy sebezhet\u0151s\u00e9get (CVE-2025-6019) a libblockdev k\u00f6nyvt\u00e1rban, amely lehet\u0151v\u00e9 teszi, hogy a h\u00e1tt\u00e9rfolyamat udisks manipul\u00e1l\u00e1s\u00e1val root jogosults\u00e1gokat szerezz\u00fcnk a rendszeren. Az exploit protot\u00edpus\u00e1nak m\u0171k\u00f6d\u00e9s\u00e9t az Ubuntu, Debian, Fedora \u00e9s openSUSE Leap 15 k\u00f6rnyezet\u00e9ben d\u00e9montr\u00e1lt\u00e1k. <\/p>\n
Az udisks folyamat szinte minden Linux disztrib\u00faci\u00f3ban alkalmaz\u00e1sra ker\u00fcl, \u00e9s D-Bus interf\u00e9szt biztos\u00edt t\u00e1rol\u00f3k m\u0171veleteinek v\u00e9grehajt\u00e1s\u00e1ra, mint p\u00e9ld\u00e1ul csatol\u00e1s \u00e9s form\u00e1z\u00e1s. A t\u00e1rol\u00f3kra vonatkoz\u00f3 m\u0171veletek v\u00e9grehajt\u00e1s\u00e1hoz az udisks a libblockdev k\u00f6nyvt\u00e1r funkci\u00f3it h\u00edvja meg. Az udisks el\u00e9r\u00e9se alap\u00e9rtelmez\u00e9s szerint csak azok sz\u00e1m\u00e1ra nyitott, akik az 'allow_active' kontextusban dolgoznak, azaz fizikailag hozz\u00e1f\u00e9rnek a sz\u00e1m\u00edt\u00f3g\u00e9phez, \u00e9s a helyi konzolon kereszt\u00fcl csatlakoznak, vagy egy grafikus munkamenetet ind\u00edtanak. A t\u00e1voli felhaszn\u00e1l\u00f3k, p\u00e9ld\u00e1ul akik SSH-n kereszt\u00fcl csatlakoznak, nem tartoznak ebbe a kontextusba, \u00e9s k\u00f6zvetlen\u00fcl nem tudj\u00e1k kihaszn\u00e1lni a sebezhet\u0151s\u00e9get. <\/p>\n
E korl\u00e1toz\u00e1s megker\u00fcl\u00e9s\u00e9re egy tr\u00fckk alkalmazhat\u00f3, amely a felhaszn\u00e1l\u00f3i szolg\u00e1ltat\u00e1s ind\u00edt\u00e1s\u00e1hoz kapcsol\u00f3d\u00f3 systemctl utas\u00edt\u00e1s manipul\u00e1l\u00e1s\u00e1val k\u00e9pes felemelni az azonos\u00edt\u00e1si szintet 'allow_active' szintre, amit a polkitd helyi munkamenetk\u00e9nt \u00e9rz\u00e9kel. A m\u00f3dszer l\u00e9nyege, hogy a polkitd fizik\u00e1lis hozz\u00e1f\u00e9r\u00e9s jelenl\u00e9t\u00e9t \u00e9szleli, \u00e9s az 'allow_active' szintet k\u00f6zvetett jelek alapj\u00e1n rendeli hozz\u00e1, amelyeket manipul\u00e1lni lehet. A m\u00f3dszer korl\u00e1toz\u00e1sa, hogy a polkitd \u00e1tver\u00e9s\u00e9hez a rendszerben m\u00e1r akt\u00edv helyi felhaszn\u00e1l\u00f3i munkamenet sz\u00fcks\u00e9ges fizik\u00e1lis hozz\u00e1f\u00e9r\u00e9ssel. <\/p>\n
A m\u00e1sodik m\u00f3dszer az 'allow_active' jogok megszerz\u00e9s\u00e9re a PAM (Pluggable Authentication Modules) sebezhet\u0151s\u00e9g\u00e9nek (CVE-2025-6018) kihaszn\u00e1l\u00e1sa, amelyet a Qualys kutat\u00f3i fedeztek fel a libblockdev sebezhet\u0151s\u00e9g\u00e9nek elemz\u00e9se sor\u00e1n. Ez a sebezhet\u0151s\u00e9g lehet\u0151v\u00e9 teszi b\u00e1rmely felhaszn\u00e1l\u00f3, bele\u00e9rtve az SSH-n csatlakoz\u00f3kat, hogy 'allow_active' kontextusban v\u00e9gezzen m\u0171veleteket. A probl\u00e9ma a PAM be\u00e1ll\u00edt\u00e1saira specifikus az openSUSE Leap 15 \u00e9s a SUSE Linux Enterprise 15 rendszereken, \u00e9s kiz\u00e1r\u00f3lag ezekben a disztrib\u00faci\u00f3kban jelentkezik. <\/p>\n
A pam_env modul az openSUSE \u00e9s SUSE rendszerekben alap\u00e9rtelmezetten enged\u00e9lyezi a ~\/.pam_environment f\u00e1jl olvas\u00e1s\u00e1t. Ezen f\u00e1jl seg\u00edts\u00e9g\u00e9vel a felhaszn\u00e1l\u00f3 be\u00e1ll\u00edthatja az XDG_SEAT=seat0 \u00e9s XDG_VTNR=1 k\u00f6rnyezeti v\u00e1ltoz\u00f3kat, amelyek a tov\u00e1bbi feldolgoz\u00e1s sor\u00e1n a felhaszn\u00e1l\u00f3 fizikai jelenl\u00e9t\u00e9nek fokozott jelk\u00e9nt lesznek \u00e9rtelmezve, m\u00e9g akkor is, ha a bejelentkez\u00e9s val\u00f3j\u00e1ban SSH-n kereszt\u00fcl t\u00f6rt\u00e9nt. A pam_env modul SSH kapcsol\u00f3d\u00e1skor is aktiv\u00e1l\u00f3dik Debian 12 \u00e9s Ubuntu 24.04 rendszerekben (Debian 13 \u00e9s Ubuntu 24.10+ eset\u00e9n le van tiltva), azonban a k\u00f6rnyezeti v\u00e1ltoz\u00f3k be\u00e1ll\u00edt\u00e1sa ezeken a disztrib\u00faci\u00f3kon nem haszn\u00e1lhat\u00f3 a \u201eallow_active\u201d szint el\u00e9r\u00e9s\u00e9re, mivel a pam_env a pam_systemd modul bet\u00f6lt\u00e9se ut\u00e1n, a v\u00e9gs\u0151 szakaszban ker\u00fcl aktiv\u00e1l\u00e1sra, \u00e9s a be\u00e1ll\u00edtott k\u00f6rnyezeti v\u00e1ltoz\u00f3k nem befoly\u00e1solhatj\u00e1k a munkamenet param\u00e9tereit. <\/p>\n
A libblockdev sebezhet\u0151s\u00e9ge eset\u00e9n a t\u00e1mad\u00f3 k\u00e9pes ciklus \u00fczemm\u00f3dban csatolni egy \u00f6nk\u00e9nyes f\u00e1jlrendszer k\u00e9pet, egy SUID root z\u00e1szl\u00f3val rendelkez\u0151 futtathat\u00f3 f\u00e1jlt, vagy egy speci\u00e1lis eszk\u00f6zt (\/dev\/mem) elhelyezve a k\u00e9pen a lemezekhez vagy a mem\u00f3ria alacsony szint\u0171 hozz\u00e1f\u00e9r\u00e9se \u00e9rdek\u00e9ben. Ezeket a t\u00e1mad\u00e1sokat a f\u00e1jlrendszer k\u00e9pek nosuid \u00e9s nodev z\u00e1szl\u00f3kkal t\u00f6rt\u00e9n\u0151 csatol\u00e1s\u00e1val blokkolja a rendszer, azonban a libblockdev sebezhet\u0151s\u00e9ge lehet\u0151v\u00e9 teszi a k\u00e9pek nosuid \u00e9s nodev z\u00e1szl\u00f3k n\u00e9lk\u00fcli csatol\u00e1s\u00e1t. A sebezhet\u0151s\u00e9g l\u00e9nyege, hogy az udisks lehet\u0151v\u00e9 teszi a \u201eallow_active\u201d szint\u0171 hozz\u00e1f\u00e9r\u00e9ssel rendelkez\u0151 felhaszn\u00e1l\u00f3k sz\u00e1m\u00e1ra, hogy megv\u00e1ltoztass\u00e1k f\u00e1jlrendszereik m\u00e9ret\u00e9t, \u00e9s a libblockdev ezen m\u0171velet v\u00e9grehajt\u00e1sa sor\u00e1n ideiglenesen csatolja a f\u00e1jlrendszert nosuid \u00e9s nodev z\u00e1szl\u00f3k be\u00e1ll\u00edt\u00e1sa n\u00e9lk\u00fcl. <\/p>\n
Ez\u00e9rt a t\u00e1mad\u00e1s l\u00e9nyege, hogy l\u00e9trehoz egy ciklus k\u00e9sz\u00fcl\u00e9ket egy XFS f\u00e1jlrendszer k\u00e9pb\u0151l, amelyben egy suid root f\u00e1jl tal\u00e1lhat\u00f3, elind\u00edtja a ciklus k\u00e9sz\u00fcl\u00e9k m\u00e9ret\u00e9nek megv\u00e1ltoztat\u00e1s\u00e1ra ir\u00e1nyul\u00f3 m\u0171veletet, \u00e9s figyeli, mikor csatlakozik a \/tmp\/blockdev* k\u00f6nyvt\u00e1rhoz: victim> killall -KILL gvfs-udisks2-volume-monitor victim> udisksctl loop-setup --file .\/xfs.image --no-user-interaction Mapped file .\/xfs.image as \/dev\/loop0. victim> while true; do \/tmp\/blockdev*\/bash -c 'sleep 10; ls -l \/tmp\/blockdev*\/bash' && break; done 2>\/dev\/null & victim> gdbus call --system --dest org.freedesktop.UDisks2 --object-path \/org\/freedesktop\/UDisks2\/block_devices\/loop0 --method org.freedesktop.UDisks2.Filesystem.Resize 0 '{}' Error: GDBus.Error:org.freedesktop.UDisks2.Error.Failed: Error resizing filesystem on \/dev\/loop0: Failed to unmount '\/dev\/loop0' after resizing it: target is busy -r-sr-xr-x. 1 root root 1406608 Jun 18 09:42 \/tmp\/blockdev.RSM429\/bash victim> \/tmp\/blockdev*\/bash -p victim# id uid=65534(nobody) gid=65534(nobody) euid=0(root) groups=65534(nobody) <\/p>\n
A libblockdev sebezhet\u0151s\u00e9ge eddig csak jav\u00edt\u00f3csomagok form\u00e1j\u00e1ban ker\u00fclt orvosl\u00e1sra. Az \u00faj verzi\u00f3 \u00e1llapot\u00e1t vagy a disztrib\u00faci\u00f3kban t\u00f6rt\u00e9n\u0151 jav\u00edt\u00e1s el\u0151k\u00e9sz\u00edt\u00e9s\u00e9t a k\u00f6vetkez\u0151 oldalakon lehet ellen\u0151rizni (ha az oldal nem \u00e9rhet\u0151 el, akkor a disztrib\u00faci\u00f3 fejleszt\u0151i m\u00e9g nem kezdt\u00e9k el a probl\u00e9ma vizsg\u00e1lat\u00e1t): Debian, Ubuntu, Fedora, SUSE\/openSUSE, RHEL, Gentoo \u00e9s Arch (1, 2). A sebezhet\u0151s\u00e9g blokkol\u00e1s\u00e1ra alternat\u00edvak\u00e9nt m\u00f3dos\u00edthat\u00f3 a hozz\u00e1f\u00e9r\u00e9si szab\u00e1ly az \u201eorg.freedesktop.udisks2.modify-device\u201d m\u0171velethez a polkit-ben, \u00fagy, hogy a \/usr\/share\/polkit-1\/actions\/org.freedesktop.UDisks2.policy f\u00e1jlban a \u201eallow_active\u201d param\u00e9ter \u00e9rt\u00e9k\u00e9t \u201eyes\u201d-r\u0151l \u201eauth_admin\u201d-ra v\u00e1ltoztatjuk. <\/p>\n
Kiemelhet\u0151, hogy n\u00e9h\u00e1ny \u00f3r\u00e1val ezel\u0151tt felfedezett sebezhet\u0151s\u00e9g (CVE-2025-6020) a linux-pam csomagban lehet\u0151v\u00e9 teszi, hogy a helyi felhaszn\u00e1l\u00f3 root jogokat szerezzen. A pam_namespace modul nem ellen\u0151rizte megfelel\u0151en a felhaszn\u00e1l\u00f3 \u00e1ltal ellen\u0151rz\u00f6tt f\u00e1jl\u00fatvonalakat, \u00edgy a szimbolikus hivatkoz\u00e1sok manipul\u00e1l\u00e1s\u00e1val \u00e9s verseny\u00e1llapot el\u00e9r\u00e9s\u00e9vel lehet\u0151s\u00e9g ny\u00edlt privilegiz\u00e1lt f\u00e1jlok fel\u00fcl\u00edr\u00e1s\u00e1ra a rendszeren. A sebezhet\u0151s\u00e9get a linux-pam 1.7.1-es kiad\u00e1s\u00e1ban orvosolt\u00e1k. Az \u00faj csomagverzi\u00f3 \u00e1llapot\u00e1t vagy a hibajav\u00edt\u00e1s el\u0151k\u00e9sz\u00edt\u00e9s\u00e9t az al\u00e1bbi oldalakon ellen\u0151rizheti: Debian, Ubuntu, Fedora, SUSE\/openSUSE, RHEL, Gentoo \u00e9s Arch (1, 2). \u041a\u043e\u043c\u043f\u0430\u043d\u0438\u044f Qualys \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2025-6019) \u0432 \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0435 libblockdev, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0443\u044e \u0447\u0435\u0440\u0435\u0437 \u043c\u0430\u043d\u0438\u043f\u0443\u043b\u044f\u0446\u0438\u0438 \u0441 \u0444\u043e\u043d\u043e\u0432\u044b\u043c \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u043c udisks \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u043f\u0440\u0430\u0432\u0430 root \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435. \u0420\u0430\u0431\u043e\u0442\u0430 \u043f\u0440\u043e\u0442\u043e\u0442\u0438\u043f\u0430 \u044d\u043a\u0441\u043f\u043b\u043e\u0438\u0442\u0430 \u043f\u0440\u043e\u0434\u0435\u043c\u043e\u043d\u0441\u0442\u0440\u0438\u0440\u043e\u0432\u0430\u043d\u0430 \u0432 Ubuntu, Debian, Fedora \u0438 openSUSE Leap 15. \u041f\u0440\u043e\u0446\u0435\u0441\u0441 udisks \u043f\u0440\u0438\u043c\u0435\u043d\u044f\u0435\u0442\u0441\u044f \u043f\u0440\u0430\u043a\u0442\u0438\u0447\u0435\u0441\u043a\u0438 \u0432\u043e \u0432\u0441\u0435\u0445 \u0434\u0438\u0441\u0442\u0440\u0438\u0431\u0443\u0442\u0438\u0432\u0430\u0445 Linux \u0438 \u043f\u0440\u0435\u0434\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 \u0438\u043d\u0442\u0435\u0440\u0444\u0435\u0439\u0441 D-Bus \u0434\u043b\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u0439 \u0441 \u043d\u0430\u043a\u043e\u043f\u0438\u0442\u0435\u043b\u044f\u043c\u0438, \u0442\u0430\u043a\u0438\u0445 \u043a\u0430\u043a \u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0438 \u0444\u043e\u0440\u043c\u0430\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435. \u0414\u043b\u044f […]<\/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-137763","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\udd47 Sebezhet\u0151s\u00e9gek a PAM-ban \u00e9s a libblockdev-ben, amelyek lehet\u0151v\u00e9 teszik a root jogok megszerz\u00e9s\u00e9t a rendszeren | ProHoster","description":"A Qualys c\u00e9g felfedezett egy sebezhet\u0151s\u00e9get (CVE-2025-6019) a libblockdev k\u00f6nyvt\u00e1rban, amely lehet\u0151v\u00e9 teszi a root jogok megszerz\u00e9s\u00e9t a h\u00e1tt\u00e9rfolyamat, az udisks manipul\u00e1l\u00e1s\u00e1val.","canonical_url":"https:\/\/prohoster.info\/hu\/blog\/news\/uyazvimosti-v-pam-i-libblockdev-pozvolyayushhie-poluchit-prava-root-v-sisteme","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"hu_HU","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\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u0432 PAM \u0438 libblockdev, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0435 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