Excel .xls help.....

General technological topics without their own forum go here

Excel .xls help.....

Post by Murse512 on Sun Dec 02, 2012 10:21 pm
([msg=71490]see Excel .xls help.....[/msg])

I have placed a password to open on one of my excel files and I cant remember it. I know there are several cracking/decryption programs available for this but they all cost around 30$ (which is crazy for one file). I recently downloaded backtrack 5 in hopes of finding something suitable to find my password. Does anyone have any clues or ideas on how to recover my password? I know the file has a 40bit rc4 encryption and I have a rough idea of what the password is. Thanks in advance.
Murse512
New User
New User
 
Posts: 2
Joined: Sun Dec 02, 2012 10:17 pm
Blog: View Blog (0)


Re: Excel .xls help.....

Post by WallShadow on Mon Dec 03, 2012 12:20 am
([msg=71493]see Re: Excel .xls help.....[/msg])

I don't know about any programs that do crack it, but I imagine it that there are plenty of brute forcing algorithms against rc4 because a 40-bit key is pathetically small. A modern PC with a brute force program should be able to crack it in no more than an hour.
User avatar
WallShadow
Contributor
Contributor
 
Posts: 621
Joined: Tue Mar 06, 2012 9:37 pm
Blog: View Blog (0)


Re: Excel .xls help.....

Post by Murse512 on Mon Dec 03, 2012 5:56 am
([msg=71495]see Re: Excel .xls help.....[/msg])

After doing a little research, I am pretty sure John the ripper can do rc4's. I have no idea how to tell john to decrypt the rc4 part of a file though. I know jtr usually deals with hashes. I know you have to specify the kind of brute force attack with jtr too. Any clues on how to go about doing this?
Murse512
New User
New User
 
Posts: 2
Joined: Sun Dec 02, 2012 10:17 pm
Blog: View Blog (0)


Re: Excel .xls help.....

Post by bwnihilanth on Mon Dec 03, 2012 5:01 pm
([msg=71512]see Re: Excel .xls help.....[/msg])

I think you can get a free trial of lophtcrack on the lopht website
bwnihilanth
New User
New User
 
Posts: 2
Joined: Mon Dec 03, 2012 4:32 pm
Blog: View Blog (0)



Return to General

Who is online

Users browsing this forum: No registered users and 0 guests