I have a list of login credentials (usernames and passwords) that I wanna keep safe. I'm planning to keep it in an encrypted Veracrypt virtual drive with AES, SHA-512, and an 8-character password. Is this safe?
On a supercomputer or botnet, this will take 4 hours.
You should use at least 12 even beyond for 16 characters or better and the password must include small and capitals letters, numerals, punctuations, and symbols.
As a suggestion, you should use password managers that designed for this kind of problems.
"Safe" is relative. In general Veracrypt has a good reputation and supports strong crypto.
Assuming reasonable use, your weakest link is your stated 8-character password.
It may be safe enough depending upon the password and the expected threat, but why limit yourself to an 8-character password?
Veracrypt supports "pass phrases" up to 64 characters. You can make an easy to remember multiword sentence that is potentially much stronger than 8 characters.
*Granted it's always possible to make poor passwords and phrases.*
Additionally, Veracrypt supports a user custom PIM (Personal Iterations Multiplier). This creates an alternate iteration count from that of the default, which means brute forcing has to account for the custom PIM as well as the password/phrase. Of course this also means you have to remember this custom PIM as well.
If for whatever reason you feel you need to use only an 8-character password, I'd suggest also using a custom PIM.
Storing credentials in an encrypted Veracrypt container would be a great thing, but you should consider the following:
a stronger password for the accessing the container: 16 characters should be a minimum to consider
make sure the operating system you access the container from is not compromised: if you have an infected OS stealing your container password you become compromised
This solution would be better than a known password manager because against password managers there are known vulnerabilities and exploits.
A new study by researchers at Independent Security Evaluators (ISE) concludes: Top password manager products have fundamental flaws that expose the data they are designed to protect, rendering them no more secure than saving passwords in a text file.
"100 percent of the products that ISE analyzed failed to provide the security to safeguard a user’s passwords as advertised,” says ISE CEO Stephen Bono. “Although password managers provide some utility for storing login/passwords and limit password reuse, these applications are a vulnerable target for the mass collection of this data through malicious hacking campaigns.”