Resources about Firewall Rules for Linux
An e-mail with an apparently harmless attachment. A link to a malicious website. A prepared zip archive with malware, or a payload embedded in a PDF document is all it takes to infiltrate a network.
Some years ago, I had a similar incident, which led me to dig deeper in the subject to implement appropriate countermeasures.
It is by then that I have translated this Pocket Reference Guide from O'Reilly into Arabic.
You can access the book by clicking on the cover below: