How long before our website bounce back after Google Penalty?

[SirAdri11]

One of our client websites got recently hacked. In a span of 4 days, it received random backlinks from random websites with random anchor texts. We are already in good standing for some of the keywords we are tracking and the attack got us a penalty from Google and we lost our rankings, moving out of the top 500.

We already disavowed these dirty backlinks though we never really diagnosed where these came from. How long do you think our client's website will bounce back from the penalty?