Author: Stewart Moss

How to create a simple brute forcing engine in a delphi class.

Answer:

1   {--------------------------------------------------------------------------
2   ---
3    Unit Name: classThreadBruteForce
4   
5    Version: 1.0
6   
7    Release Date: 21-Aug-2002
8   
9    Compiler directives:
10  
11      TINY     - removes unnessecary error messages. test that output
12                 is not empty
13      and
14      OPTIMIZE (less information is available)
15  
16   Purpose:
17  
18   Description:
19  
20      A TThread which generates brute force combinations through the
21      onDo event.
22  
23   Notes:
24      Charset contains the characters (these are sorted internally)
25      onFinished event provided
26  
27      Not exactly fast but it does the job.
28  
29      Use it like this:-
30  
31      brute := TBruteThread.create(true);
32      brute.charset := 'abcdefghijklmnopqrstuvwxyz';  // Chars to brute
33      brute.numCharacters := 5;                       // Max chars
34      brute.onDo := Form1ThreadOnDo;
35      brute.resume;
36  
37   Dependancies:
38  
39   History:
40  
41          Copyright 2002 by Stewart Moss
42          All rights reserved.
43  -----------------------------------------------------------------------------}
44  
45  unit classBruteForce;
46  
47  interface
48  uses classes, sysutils;
49  
50  type
51    TBruteThread = class(TThread)
52    private
53      FNumChars: Integer;
54      FCharset: string;
55      FonDo: TNotifyEvent;
56      FonFinished: TNotifyEvent;
57  
58      CharCount: string;
59      minChar: char;
60      maxChar: char;
61      imaxChar: integer;
62  
63      incBruteLock: boolean;
64      // locks the incBrute function
65  
66      procedure init;
67      function incBrute(posi: integer): integer;
68      function StringBubbleSort(StrIn: string): string;
69  
70    public
71  {$IFNDEF OPTIMIZE}
72      BruteCount: integer; // not recommended on large bruteforce,
73      // use your own counter
74  {$ENDIF}
75      BruteResult: string;
76  
77      procedure execute; override;
78  
79    published
80  
81      property onDo: TNotifyEvent read FonDo write FonDo;
82      property onFinished: TNotifyEvent read FonFinished write FonFinished;
83  
84      property CharSet: string read FCharset write FCharset;
85      property numCharacters: Integer read FNumChars write FNumChars;
86  
87    end;
88  
89  implementation
90  
91  { TBruteThread }
92  
93  procedure TBruteThread.execute;
94  var
95    loop: integer;
96    tmpstr: string;
97  begin
98    if FNumChars <= 0 then
99    begin
100 {$IFNDEF TINY}
101     raise exception.create('invalid Numchars');
102 {$ENDIF}
103 {$IFDEF TINY}
104     exit;
105 {$ENDIF}
106   end;
107 
108   if FCharSet = '' then
109   begin
110 {$IFNDEF TINY}
111     raise exception.create('Charset is blank');
112 {$ENDIF}
113 {$IFDEF TINY}
114     exit;
115 {$ENDIF}
116   end;
117 
118   init;
119 
120   while (not terminated) do
121   begin
122     if incbrute(1) > FNumChars then
123       break;
124 
125     loop := 0;
126     bruteresult := '';
127     while loop < FNumChars do
128     begin
129       inc(loop);
130       if charcount[loop] = #0 then
131         break;
132 
133       // speed optimization
134       tmpstr := BruteResult;
135       BruteResult := tmpstr + charcount[loop];
136     end;
137 {$IFNDEF OPTIMIZE}
138     inc(Brutecount);
139 {$ENDIF}
140 
141     if assigned(onDo) then
142       onDo(Self);
143   end;
144 
145   if assigned(onFinished) then
146     onFinished(Self);
147 end;
148 
149 {-----------------------------------------------------------------------------
150   Procedure: incBrute
151   Arguments: posi: integer
152   Result:    integer
153  
154   Purpose: Recurive
155 
156   Description:
157     This function brutes
158 
159       Copyright 2002 by Stewart Moss
160       All rights reserved.
161 -----------------------------------------------------------------------------}
162 
163 function TBruteThread.incBrute(posi: integer): integer;
164 var
165   tmpint: integer;
166   bufferpos: integer;
167 begin
168   result := posi;
169   bufferpos := pos(charcount[posi], FCharset);
170   charcount[posi] := FCharset[bufferpos + 1];
171   if FCharset[Bufferpos] = maxchar then
172   begin
173     charcount[posi] := minchar;
174     tmpint := incBrute(posi + 1);
175     if tmpint > FnumChars then
176       result := tmpint;
177   end;
178 end;
179 
180 procedure TBruteThread.init;
181 var
182   loop: integer;
183 begin
184   FCharSet := StringBubbleSort(FCharset);
185   minchar := FCharset[1];
186   maxChar := FCharset[length(FCharset)];
187   imaxchar := ord(MaxChar);
188   charcount := '';
189   for loop := 1 to FNumChars do
190   begin
191     charcount := charcount + #0;
192   end;
193 {$IFNDEF OPTIMIZE}
194   Brutecount := 0;
195 {$ENDIF}
196 
197 end;
198 
199 function TBruteThread.StringBubbleSort(StrIn: string): string;
200 var
201   i, j: Integer;
202   temp: Char;
203   tmplen: integer;
204 begin
205   tmplen := length(StrIn);
206   for i := 1 to tmplen do
207     for j := 1 to tmplen do
208       if strIn[i] < StrIn[j] then
209       begin
210         temp := StrIn[i];
211         StrIn[i] := StrIn[j];
212         StrIn[j] := temp;
213       end;
214   Result := strIn;
215 end;
216 
217 end.