Cracking files

Most password‐protected files can be cracked in seconds or minutes. You can demonstrate this “wow factor” security vulnerability to users and management. Here’s a hypothetical scenario that could occur in the real world:

1.  Your CFO wants to send some confidential financial information in an Excel spreadsheet to a company board member.

2.  She protects the spreadsheet by assigning it a password during the   file‐save process in Excel.

3.  For good measure, she uses WinZip to compress the file and adds another password to make it  really  secure.

4.  The CFO sends the spreadsheet as an e‐mail attachment, assuming that the e‐mail will reach its destination.
 The financial advisor’s network has content filtering, which monitors incoming e‐mails for keywords and file attachments. Unfortunately, the financial advisory firm’s network administrator is looking in the contentfiltering system to see what’s coming in.

5.  This rogue network administrator finds the e‐mail with the confidential attachment, saves the attachment, and realizes that it’s password protected.

6.  The network administrator remembers a great password‐cracking tool available from ElcomSoft called Advanced Archive Password Recovery (www.elcomsoft.com/archpr.html) that can help him out so he proceeds to use it to crack the password.

Cracking password‐protected files is as simple as that! Now all that the rogue network administrator must do is forward the confidential spreadsheet to his buddies or to the company’s competitors.

If you carefully select the right options in Advanced Archive Password Recovery, you can drastically shorten your testing time. For example, if you know that a password is not over five characters long or is lowercase letters only, you can cut the cracking time in half.

I recommend performing these file‐password‐cracking tests on files that you capture with a content filtering or network analysis tool. This is a good way to determine whether your users are adhering to policy and using adequate passwords to protect sensitive information they’re sending.

Countermeasures
The best defense against weak file password protection is to require your users to use a stronger form of file protection, such as PGP, or the AES encryption that’s built in to WinZip, when necessary. Ideally, you don’t want to rely on users to make decisions about what they should use to secure sensitive information, but it’s better than nothing. Stress that a file encryption mechanism, such as a password‐protected Zip file, is secure only if users keep their passwords confidential and never transmit or store them in unsecure cleartext (such as in a separate e‐mail).

If you’re concerned about unsecure transmissions through e‐mail, consider using a content‐filtering system or a data loss–prevention system to block all outbound e‐mail attachments that aren’t protected on your e‐mail server.

NOTE: This is for educational purpose only we are not responsible for any type of inconvenience caused by reader.

Share This:

Be the first to comment

Leave a Reply

Your email address will not be published.


*