An auditor is reviewing the logs from a web application to determine the source of an incident. The web application architecture includes an internet-accessible application load balancer, a number of web servers in a private subnet, application servers, and one database server in a tiered configuration. The application load balancer cannot store the logs. The following are sample log snippets:
Web server logs:
192.168.1.10 - - [24/Oct/2020 11:24:34 +05:00] "GET /bin/bash" HTTP/1.1" 200 453 Safari/536.36
192.168.1.10 - - [24/Oct/2020 11:24:35 +05:00] "GET / HTTP/1.1" 200 453 Safari/536.36 Application server logs:
24/Oct/2020 11:24:34 +05:00 - 192.168.2.11 - request does not match a known local user. Querying DB
24/Oct/2020 11:24:35 +05:00 - 192.168.2.12 - root path. Begin processing Database server logs:
24/Oct/2020 11:24:34 +05:00 [Warning] 'option read_buffer_size1 unassigned value 0 adjusted to 2048
24/Oct/2020 11:24:35 +05:00 [Warning] CA certificate ca.pem is self-signed.
Which of the following should the auditor recommend to ensure future incidents can be traced back to the sources?