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Mastering Linux Security and Hardening

You're reading from   Mastering Linux Security and Hardening Secure your Linux server and protect it from intruders, malware attacks, and other external threats

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Product type Paperback
Published in Jan 2018
Publisher
ISBN-13 9781788620307
Length 376 pages
Edition 1st Edition
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Author (1):
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Donald A. Tevault Donald A. Tevault
Author Profile Icon Donald A. Tevault
Donald A. Tevault
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Table of Contents (12) Chapters Close

Preface 1. Running Linux in a Virtual Environment FREE CHAPTER 2. Securing User Accounts 3. Securing Your Server with a Firewall 4. Encrypting and SSH Hardening 5. Mastering Discretionary Access Control 6. Access Control Lists and Shared Directory Management 7. Implementing Mandatory Access Control with SELinux and AppArmor 8. Scanning, Auditing, and Hardening 9. Vulnerability Scanning and Intrusion Detection 10. Security Tips and Tricks for the Busy Bee 11. Other Books You May Enjoy

Using chmod to set permissions values on files and directories

On Unix and Linux systems, you would use the chmod utility to set permissions values on files and directories. You can set permissions for the user of the file or directory, the group that's associated with the file or directory, and others. The three basic permissions are:

  • r: This indicates a read permission.
  • w: This is for a write permission.
  • x: This is the executable permission. You can apply it to any type of program file, or to directories. If you apply an executable permission to a directory, authorized people will be able to cd into it.

Do an ls -l on a file, and you'll see something like this:

-rw-rw-r--. 1 donnie donnie     804692 Oct 28 18:44 yum_list.txt

The first character of this line indicates the type of file. In this case, we see a dash, which indicates a regular file. (A regular file is...

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