CIS Benchmark is a machine wise checklist to check, harden and standardize security of a machine.
https://www.cisecurity.org/cis-benchmarks
Can’t solve? you need to make your Linux knowledge stronger.
https://web-check.xyz/ was introduced. Sir also told us to research on the terms on the result.
Also check the external tools like dnsdumpstar listed there.
Reverse Image Search: https://tineye.com/
You can utilize so many tools for ONSIT.
https://start.me/p/rx6Qj8/nixintel-s-osint-resource-list
There are many ONSIT methodologies: https://github.com/ahmad0x1/ARWAD/blob/main/ARWAD_Methodology.jpg
Another one is Jasson Haddix’s methodology: https://github.com/jhaddix/tbhm
ONSIT guide: