Book Image

Security with Go

By : John Daniel Leon
Book Image

Security with Go

By: John Daniel Leon

Overview of this book

Go is becoming more and more popular as a language for security experts. Its wide use in server and cloud environments, its speed and ease of use, and its evident capabilities for data analysis, have made it a prime choice for developers who need to think about security. Security with Go is the first Golang security book, and it is useful for both blue team and red team applications. With this book, you will learn how to write secure software, monitor your systems, secure your data, attack systems, and extract information. Defensive topics include cryptography, forensics, packet capturing, and building secure web applications. Offensive topics include brute force, port scanning, packet injection, web scraping, social engineering, and post exploitation techniques.
Table of Contents (15 chapters)

Finding writable files

Once you gain access to a system, you want to start exploring. Typically, you will look for ways to escalate your privilege or maintain persistence. A great way to look for methods of persistence is to identify which files have write permissions.

You can look at the file permission settings and see if you or everyone has write permission. You can look explicitly for modes such as 777, but a better way is to use a bitmask and look specifically at the write permission bits.

The permissions are represented by several bits: the user permissions, group permissions, and finally, the permissions for everyone. The string representation of a 0777 permission would look like this: -rwxrwxrwx. The bit we are interested in is the one that gives everyone the write permission, which is represented by --------w-.

The second bit is the only one we care about, so we will...