Outdated software is one of the most common vulnerabilities during competition hardening.
Linux
Check service versions:
nginx -v
apache2 -v
mysql --version
psql --version
Update packages:
sudo apt update
sudo apt upgrade
Also review web application runtimes, plugins, and extensions. Update or remove anything that is no longer needed.
Check container images:
docker images
Replace old or untrusted images with current patched versions.
Windows
Check installed programs:
wmic product get name,version
Review versions for IIS-hosted applications, SQL Server, Exchange, and any third-party plugins. Run Windows Update if needed.
For Microsoft Exchange specifically, prioritize the latest available security updates because it is commonly targeted.