PSafe

Putting all of your passwords in one well-defined location is like putting all of your eggs in one basket. The advantage is that it is easier to keep track of your eggs. If someone breaks into your egg basket, the disadvantages are obvious.

Many of the following security concerns are not unique to PSafe. Any program that accepts passwords for authentication is subject to a number of possible attacks.

File Storage

The first time you save a password, PSafe will create a hidden directory named .psafe in your home directory. As a precaution, this directory is created so that other users do not have permission to see the contents. If your home directory is on AFS or some other shared filesystem, you may have to take additional steps to ensure that others do not have access. (They would still need to know your password to decrypt the file, though.)

For example, in AFS, you can see the access settings using the following command:

fs listacl ~/.psafe

Network Transmission

If you are logging in over a network, be aware that everything you see on the screen and everything you type (including your PSafe Master Password) goes over the network too. Use a secure client, such as ssh. The commonly used 'telnet' program does no encryption, so it is inherently unsafe.

Memory

It is theoretically possible for a system administrator to examine a memory image of PSafe while it is running in order to see your decrypted passwords. Do not use PSafe if you distrust your system admins.

Program Hacks

Any user who can modify the PSafe program itself can change it to tell them your password when you enter it. Make sure you trust whoever has write access to the psafe program and Python, probably root.

Similarly, anybody who had access to PSafe on the site that you installed it from could also have modified the application to send them your passwords.

Path Attacks

If your PATH environment variable contains entries before the one that points to psafe, anyone with write access to those directories can create a program called 'psafe' there and it will override the one you thought you were using. In general, don't add directories to your path if you don't trust the owner of the directory.

Screen Memory

When you view passwords using PSafe, it shows them right on the screen. Maybe somebody will eventually add a paste option that will merely insert the password into the clipboard, but even then, it's in the clipboard memory, unless you are careful to clear it out before you walk away from the workstation.

Choice of Password

PSafe does not force you to use a good, hard to guess password. In fact, you can use no password at all, in which case it stores everything in plain text, making you totally reliant on the security of the filesystem.

Implementation Details

PSafe uses a flexible file storage format that can be easily extended to support other encryption algorithms. It also supports any number of additional fields per password entry.

If you export your file without choosing an export password, you can see the format. In fact, you can edit this plain text file and import it back into an encrypted PSafe file. If you add additional fields to an entry (say password_hint), this information is also displayed when you view the entry.