A utility for managing an encrypted credential vault.
This hobby project was written because I finally had some time to explore Python3. It should be fine for low-value credentials, but if you are dealing with serious threat scenarios, consider alternatives. Also use 2-factor authenticiation with a separate device whenever possible.
Vault contents are protected using Fernet. This encrypts using AES128 in CBC mode and authenticates using HMAC/SHA256. Fernet's secret token comes from a user password that is key-stretched using PBKDF2 and SHA256. The iteration count for PBKDF2 was dailed in to take about 3 seconds on my 2013 Macbook Air, which comes out to 2M iterations, well over the NIST minimum guideline of 10K. Each vault file gets a unique 18 byte salt generated from urandom.
Core dumps are disabled via rlimit to reduce the chance of passwords being left in a decrypted state.
First create an empty vault. When prompted for a key you should use a very strong password. This is the one you'll have to memorize to protect your vault contents.
./pman init ~/.pman_vault
Add the new vault file to your environment. For example, a bash user might add the following to their .profile:
export PMAN_VAULT=/home/myuser/.pman_vault
To add or update a credential, use the 'set' command. The inputs are not passed via the command line to avoid exposing credentials in shell history files or via the process list.
./pman set
You can fetch a credential using the 'get' command.
./pman get mycred
You can also list all available credentials ('list') or search credentials using a substring ('search'). To avoid exposing unneeded passwords, these two commands will only show the credential name, username, description, and number of days since the entry was last updated. Once you identify the credential you want, use 'get' to fetch the details.
./pman list
You can 'remove' entries. The entry being deleted will be emitted to stdout in case you make a mistake. (You can use that information with a 'set' to recreate the entry).
./pman remove mycred
If you ever need to change the secret key for your vault, you can use the 'rekey' command. This changes both the encryption password and generates a new random salt for the vault file.
./pman rekey
- Python 3.6+
- pyca/cryptography (https://cryptography.io/)
I made design choices that I consider acceptable risks. Note that the vault is decrypted every time it is accessed. It does not "unlock" and stay open beyond the duration of the Python script.
- Decrypts all credentials at once, putting them in process memory.
- Does not explicitly clear memory after use.
For the first item, if you have sufficient access to read arbitrary memory from arbitrary processes on my computer, then my vault's secret key probably isn't safe from you anyway. (I wrote the preceeding sentence before the era of Meltdown and Spectre, but the statement is still true).
For the second item, I'm dubious you can securely clear memory using pure Python.
I back up my vault using a simple cron job copying the vault to a private S3 bucket. I have S3 versioning turned on so accidental deletions don't ruin my day.
This was written by Niek Sanders (niek.sanders@gmail.com).
This is free and unencumbered software released into the public domain.
Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.
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