Tuesday, 21 June 2011

Stealing CoreFTP Passwords with Metasploit

Well folks, I'm at it again. The next client to fall is the CoreFTP client. CoreFTP stores it's saved password in the Windows Registry.

They Can be found under HKEY_USERS\\Software\FTPWare\CoreFTP\Sites, with numbered keys for each saved site. The passwords are stored as ascii representations of their hex values(like most of the others we have seen). The ciphertext is encrypted using AES-128-ECB with a static key of "hdfzpysvpzimorhk".

So once again we rely on our ruby openssl implementations to do our decoding for us. First we pack the text from the registry:
               cipher =[encoded].pack("H*")
Then we set up our AES implementation:

                aes = OpenSSL::Cipher::Cipher.new("AES-128-ECB")
aes.padding = 0
aes.key = "hdfzpysvpzimorhk"
password= aes.update(cipher) + aes.final
return password

The  import thing to note here is the aes.padding property. This MUST be set to 0 or you will get bad decrypt errors. It took me quite a while to figure that out. The result, as usual, is an easily decrypted password. This once again highlights that static key encryption in a product like this is next to useless. Products that are going to save sensitive passwords should prompt a user to pick a master password, and sue that as an encryption key. This forever separates the encryption key from the software. It's the only real way to keep that data secure.

I submitted this module today, so it should hopefully get committed sometime in next couple of days. Keep your eyes peeled for post/windows/gather/enum_coreftp_passwords.rb

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