Creating an SRE Testing Interview VM

edit replace SELinux with AppArmor for Ubuntu

Here are a few suggestion that should be easy to set up in a VM (and I ran into over the years):

• set invalid POSIX permissions for content the web server should deliver.
• set invalid SELinux labels for content.
• break the connection between web server and a backend server (e.g. with IPTables or SELinux)
• as @anx suggested break DNS with /etc/hosts entries or invalid nameservers
• create an invalid virtual host / SNI config, making the web server reply with an incorrect vhosts' content.
• create a resource exhaustion scenario invoking the OOM-Killer.
• Block inbound connections with firewalld/iptables/nftables/SELinux.
• Create a config missing content - e.g. missing user and homedirectory, missing content, misspelled ip addresses or directory names, etc.
• Block outbound connections and serve an app from the webserver that needs them.
• Stop and disable needed services - e.g. the DB server.
• Scramble the app's db user's password or introduce a typo.
• Remove grants for the app db user.
• Fill up the filesystem.
• Introduce a failure state in the application depending on text encoding and collation (e.g. jumbled up characters, missing data).