As a security company, we deal with a lot of compromised websites. Unfortunately, in most cases, we have limited access to customer logs, which is one of the reasons why we don’t offer forensic analysis.
Sucuri offers website monitoring, protection, and clean up, but sometimes we go that extra mile and investigate how websites become compromised in the first place. This usually happens when websites become reinfected after a cleanup.
The reinfection itself can be caused by something as simple as a compromised admin user.