How to "neuter" WebWhacker V2.0

by +daQ, May 1997

With an addition by KampRET, 29 November 1997

Courtesy of fravia's page of reverse engineering
How to Neuter WebWhacker V2.0 by +daQ

Difficulty:    Beginner
Time to Fish:  1-3 hours
Tools:         W32dasm, hex editor

Webwhacker is a great tool; go to your favorite website, and run this lil app,
and you can download to your heart's content everything on that site.  BUT the
evaluation copy has a rather annoying limit;  Only 2 levels deep can you delve
into your target site.  But there is no limit how many sub levels you can
re-whack your site (the trial is limited to 20 sites you may add however)

Before we begin, let's take a look at how this program works.   The dead-listing
approach works best here (from experience... when I first tried to fix this
program to remove the level limitation, I tried Soft-Ice 3.0.  Using various
bpx's i was able to see what was getting scanned in right before the the error 
message, "You have exceeded"...but there were too many things going on). 

Back to the dead listing.
Since we already knew from running our app that the error message is "You have
exceeded the maximum number of adds for the evaluation version", lets take a
look at the string references:

* Reference To: MFC40.MFC40:NoName0098, Ord:15EAh
:0041DAF1 E8D0B80400              	   Call 004693C6
:0041DAF6 8B45F0                  	   mov eax, [ebp-10]
:0041DAF9 C7808C00000000000000    	   mov dword ptr [ebx+0000008C], 0
:0041DB03 83B89C00000002          	   cmp dword ptr [eax+0000009C], 2  ; this #2 should
                                                                      ; look familiar
:0041DB0A 7E1B                    	   jle 0041DB27
:0041DB0C 6AFF                    	   push FFFFFFFF
:0041DB0E 6A00                       push 00000000

*  Reference to String Resource ID=00139: "The maximum number of levels
has been exceeded for the evalu"
:0041DB10 688B000000              	push 0000008B

* Reference To: MFC40.MFC40:NoName0124, Ord:0424h

:0041DB15 E822B80400            	Call 0046933C
:0041DB1A 8B45F0                  	mov eax, [ebp-10]
:0041DB1D C7809C00000002000000    	mov dword ptr [ebx+0000009C], 2 ;odd...what
                              ; happens when we enter a number greater than 2?

code_segment(2) :00408E5F 8BB5F0FEFFFF mov esi, [ebp+FFFFFEF0] :00408E65 83FE02 cmp esi, 2 ; Hey, does #2 look familiar at all? :00408E68 7E13 jle 00408E7D :00408E6A 6AFF push FFFFFFFF :00408E6C BE02000000 mov esi, 2 ;what happens when we put ;more than 2 in our window? ;It becomes 2!! :00408E71 6A00 push 0 :00408E73 688B000000 push 8B ;"The maximum number of levels" * Reference To: MFC40.MFC40:NoName0124, Ord:0424h | :00408E78 E8BF040600 Call 0046933C :00408E7D 8BBDF4FEFFFF mov edi, [ebp+FFFFFEF4] :00408E83 8D4DE8 lea ecx, [ebp-18] :00408E86 E8A58AFFFF call 00401930 :00408E8B 897064 mov [eax+64], esi :00408E8E 83FEFF cmp esi, FFFFFFFF code_segment(3); * Reference To: MFC40.MFC40:NoName0410, Ord:0897h :004091AC E8E5FE0500 Call 00469096 ;read our values in :004091B1 83F801 cmp eax, 00000001 ;compare eax to 1 :004091B4 0F85A8000000 jne 00409262 ; jump if equal :004091BA 8B55C4 mov edx, [ebp-3C] ; (min whack level u :004091BD 8955E0 mov [ebp-20], edx ; can enter) :004091C0 83FA02 cmp edx, 00000002 ;compare edx to 2 (our ;maximum levels) :004091C3 7E15 jle 004091DA ;jump if less than 2 :004091C5 6AFF push FFFFFFFF :004091C7 6A00 push 00000000 :004091C9 688B000000 push 8B ;"The maximum number of levels" * Reference To: MFC40.MFC40:NoName0124, Ord:0424h | :004091CE E869010600 Call 0046933C :004091D3 C745E002000000 mov [ebp-20], 00000002 Let's start with the most obvious: In code_segment(3), we have cmp edx, 00000002 why would we wish to leave this code alone? Let's change it to 9, so it reads :004091C0 83FA09 cmp edx, 00000009 Write our file to disk (search 8B55C483FA027E15 in hexpert and change to 8B55C483FA097E15) Run our app. Hell-Yeah! One of our windows now let's us enter 9 levels as the max for whacking. But the others dont :-( *DUHH* remember there where 3 code segments? We only changed one of them, so Let's do the others too now: in code_segment(2) :00408E65 83FE02 cmp esi, 00000002 *ponder*. Change that puppy to 9 as well Side note: When looking for codes, I use Hexpert 3.0. Searching for about 10-12 hex will usually locate the code you need on the first time. *ALWAYS* search again, however, to make sure you are modifying the code you need to. You'll waste a lot of time modifying the code twice. Sometimes in Soft-Ice You'll come across codes, write them down, and modify them later. In some programs, these are duplicated in the file and all have to be changed. So what's the meaning of this? Test, Test, and Test... :) Now, Let's work on the code_segment(1). It's the same principle as all the others: load the value you want to whack, compare if It's greater than 2, give us our not-so-polite error message. :0041DB03 83B89C00000002 cmp dword ptr [eax+0000009C], 2 ;this should look ;familiar, change it to 09. Now, if you are greedy like I was the first time, I change all my 02ms to AAms. I figured, hell, 170 levels is all Imll ever need. And if a sitems got more than 170 levels, it had to be written with Microsoft Front page to be that bloated. Ahi! Remember +ORC's lesson about *NEVER* maxing out values? Well, he was right, of course... take this case: AA won't work because the maximum you may enter in our target is 100! So by throwing a number in that was greater than 100, I screwed myself over (and spent countless hours trying to figure where I went wrong). Always heed +ORc's teachings! And for our target use instead, after you have verified your re-coding, "64" hex (100 dec). Now in all these segments you can see a MOV that places the 02 into the register after the error message has been given. To make a clean crack, change those values as well (just in case for some odd reason it gets that far, we want it to max itself out cuz we don't like stupid protections). Wow. We've come a long way. WebWhacker is contentedly downloading site for us now, everybody is happy ..except, what's this? Another limit????? Side note: While I was testing, after everything is done, I reached my maximum number of adds (20 in this case) right after I had finished my last recursive test. Ok, At this point I'm a little shaky, cuz I got it working and I'm not sure whether or not the protection checks to see if number_of_adds==20 or if number_of_adds>=20. In the first case, if the number of adds is 21, it'll be false and the proggy will run. In the second, the code will always reject if greater than 20, and will have to be modified with a JMP instead of JZ or JNZ. And look! There are two "normal" code_snippets like this, and a "weird" one. * Reference To: ADVAPI32.RegQueryValueA, Ord:00E0h | :0040F79E FF1574DB4800 Call dword ptr [0048DB74] :0040F7A4 85C0 test eax, eax :0040F7A6 7513 jne 0040F7BB :0040F7A8 8D44241C lea eax, [esp + 1C] :0040F7AC 50 push eax You'll have to trust me here; I used a combinaton of "Soft-Ice and luck" and hit this location (I knew where to look by tracing (See below my original thoughts on how to beat the add thing). Change jne 0040F7BB to jmp 0040F7BB (75 to EB) and it'll work (at least, I think so..I'm sorry, sloppy cracking here. I was totally caught off guard when it hit me with the max adds, so I hadn't even prepared a registry tracking program. My apologies :) *New thought on this code section* Well, I hated myself for being so sloppy and unprepared. After downloading and running RegMon.exe (GET IT!!!!! It's the BEST TOOL for monitoring the overbloated winRegistry), I tracked the key down to HKCR\FFGEVLDOC\136\Wound In this key dwells the number of adds you have made. By editing the jmp like I previously described (jne 0040f7BB to jmp 0040F7BB, the program works like this: from regmon's output: 54 Webwhack QueryValue HKCR\FFGEVLDOC\136\Wound SUCCESS "10" 55 Webwhack SetValue HKCR\FFGEVLDOC\136\Wound SUCCESS "0" *giggle* WebWhacker now politely reset's the number of adds for us every time. :) Don't you like programs protected by 4 bytes? :) More entry-Level tutorials will follow. Next up on the list, Pioneer Pro from Caligari ( Photoshop Cracking! ( Download the Pro version of Pioneer (only the Best!), this one is a ONE BYTE CRACK!!!!! 1000's of dollars of software protected by 1 byte. Seems a little stupid, eh? Download your PegasysPhilter today and start working...this one is taking some time for me :( try running adobe4.0 and a few other apps at the same time... damn windows... May 1997, +daQ
My original thoughts on how to crack the Add Limitation sections: code_segment(4); * Referenced by a Jump at Address:00408D51(C) :00408F6F 6AFF push FFFFFFFF :00408F71 6A10 push 00000010 :00408F73 688B000000 push 8B ;"The maximum number of levels" * Reference To: MFC40.MFC40:NoName0124, Ord:0424h | :00408F78 E8BF030600 Call 0046933C :00408F7D EBB5 jmp 00408F34 :00408F7F 8B4DF0 mov ecx, [ebp-10] :00408F82 E9F9BE0100 jmp 00424E80 :00408F87 B848814700 mov eax, 00478148 Interesting. Now, from the code_segment(4) we see that the error message is jumped to from 00406C6A(C) (the ( C ) meaning a Conditional something is checking). So lets look at the code around 00406C6A: code_segment(5); * StringData Ref from Data Obj ->"Grab URL" | :00406C2C 6830664800 push 00486630 :00406C31 8D8D04FCFFFF lea ecx, [ebp+FFFFFC04] :00406C37 C645FC02 mov [ebp-04], 02 :00406C3B C645FC01 mov [ebp-04], 01 :00406C3F E8CC080100 call 00417510 :00406C44 C645FC03 mov [ebp-04], 03 :00406C48 8D8D04FCFFFF lea ecx, [ebp+FFFFFC04] :00406C4E E8AD0A0100 call 00417700 :00406C53 3D25300000 cmp eax, 00003025 :00406C58 0F85C1010000 jne 00406E1F :00406C5E B9E0BD4800 mov ecx, 0048BDE0 :00406C63 E8888C0000 call 0040F8F0 ;Something in here must set EAX ;to trigger the jump. :00406C68 85C0 test eax, eax ;This must be what triggered ;our jump. :00406C6A 0F84FD010000 je 00406E6D ;This is where our jump ;originated. :00406C70 B9E0BD4800 mov ecx, 0048BDE0 Ok, now Let's take a look at the code around 0040F8F0. Something in here must trigger our jump. * Referenced by a CALL at Addresses:00406C63, :00408D4A, :004222A8, :00422378 | :0040F8F0 E8EBFFFFFF call 0040F8E0 ;another call..this is annoying :0040F8F5 85C0 test eax, eax :0040F8F7 B801000000 mov eax, 00000001 ;DialogID_0001 :0040F8FC 7F02 jg 0040F900 :0040F8FE 33C0 xor eax, eax :0040F900 C3 ret ;Cond_jump from 0040F8FC(C) Allright, lets track down that last call: :0040F8E0 8B4114 mov eax, [ecx+14] ;call from :0040F8F0 :0040F8E3 2B4110 sub eax, [ecx+10] :0040F8E6 C3 ret Thats it????? Ok. Remeber +ORC's lessons about keeping it simple? Here we have delved, what, 4 levels into calls? Wouldn't it have been simpler to trace back to the very first one, the one we know triggers the jump, and *fix* it so it doesn't care whether or not EAX is true or false? Go back and check over that segment of code: :00406C63 E8888C0000 call 0040F8F0 ;Something in here must set EAX :00406C68 85C0 test eax, eax ;This is trigger :00406C6A 0F84FD010000 je 00406E6D ; jump good boy originated. Ok. Why not change the third call so that 01 is always loaded, and screw the rest of the code. This might work (why don't some of you test it out there?) Like I said, I don't know if this works or not. I bypassed it once, and it works straight now, so I think it is probably only checking for ==20 ..which is bad coding (who ever told you to use == inside any "if" statement was a bad teacher). Final comments on what to change: Here it is straight, the complete crack for level limits: code_segment(1); * Reference To: MFC40.MFC40:NoName0098, Ord:15EAh | :0041DAF1 E8D0B80400 Call 004693C6 :0041DAF6 8B45F0 mov eax, [ebp-10] :0041DAF9 C7808C00000000000000 mov dword ptr [ebx+0000008C], 0 :0041DB03 83B89C00000064 cmp dword ptr [eax+0000009C], 64 ;
And here a small addition by KampRET, received on 29 Nov 1997

After read +daQ essay about How to Neuter WebWhacker v2.0, i d/l
WebWhacker v3.0, 
install it, run  ... etc.

In the Properties window, Whack Depth Levels captured my attention, 
why I can't choosing the "All Levels" Depth option (grayed condition)?

Hmm.. interesting me
Run WDasm for file WW.EXE (2055168 bytes - CRC32: 392BB884)
Find reference to Dialog: "&All Levels"

:00447F7B B9C0884F00              mov ecx, 004F88C0
:00447F80 E8EEC4FEFF              call 00434473		;<2 :00447F85 85C0 test eax, eax :00447F87 0F841A000000 je 00447FA7 * Possible Reference to Dialog: DialogID_007B, CONTROL_ID:03FF, "&All Levels" | :00447F8D 68FF030000 push 000003FF :00447F92 8B4DF0 mov ecx, dword ptr [ebp-10] * Reference To: MFC42.MFC42:NoName0395, Ord:0C14h | :00447F95 E800930600 Call 004B129A :00447F9A 8945F8 mov dword ptr [ebp-08], eax :00447F9D 6A00 push 00000000 :00447F9F 8B4DF8 mov ecx, dword ptr [ebp-08] * Reference To: MFC42.MFC42:NoName0393, Ord:0A52h | :00447FA2 E8FF920600 Call 004B12A6 * Referenced by a Jump at Address:00447F87(C) | * Possible Reference to Dialog: DialogID_0001 | :00447FA7 B801000000 mov eax, 00000001 :00447FAC E900000000 jmp 00447FB1 2----------------------------------------------- :00434473 55 push ebp :00434474 8BEC mov ebp, esp :00434476 83EC04 sub esp, 00000004 :00434479 53 push ebx :0043447A 56 push esi :0043447B 57 push edi :0043447C 894DFC mov dword ptr [ebp-04], ecx :0043447F 8B45FC mov eax, dword ptr [ebp-04] :00434482 8B88E0000000 mov ecx, dword ptr [eax+000000E0] :00434488 E8ACC1FEFF call 00420639 ;<---3 :0043448D E900000000 jmp 00434492 3----------------------------------------------- :00420639 55 push ebp :0042063A 8BEC mov ebp, esp :0042063C 83EC04 sub esp, 00000004 :0042063F 53 push ebx :00420640 56 push esi :00420641 57 push edi :00420642 894DFC mov dword ptr [ebp-04], ecx :00420645 8B4DFC mov ecx, dword ptr [ebp-04] :00420648 E87EF7FFFF call 0041FDCB :0042064D A808 test al, 08 :0042064F 0F840A000000 je 0042065F * Possible Reference to Dialog: DialogID_0001 | :00420655 B801000000 mov eax, 00000001 ;<---Kena lo! (Gotcha!) :0042065A E907000000 jmp 00420666 ; Offset 1FA55 * Referenced by a Jump at Address: |:0042064F(C) | :0042065F 33C0 xor eax, eax :00420661 E900000000 jmp 00420666 * Referenced by a Jump at Addresses:0042065A(U), :00420661(U) | :00420666 5F pop edi :00420667 5E pop esi :00420668 5B pop ebx :00420669 C9 leave :0042066A C3 ret I don't know why my feeling said to change the byte at address: :) :00420655 B801000000 mov eax, 00000001 to B800000000 mov eax, 00000000 Save the changed...... run it.... Hey!!... there's no nag appear (the registration dialog), Hey!!... I can choose "All Levels" Depth or "Levels" to 9999 without a warning (max number...exceeded... :) KampRET.="=======</pre">

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