User and Group Management

Managing users and groups is a critical aspect of Linux system administration. These commands allow you to create, modify, and delete user accounts, set passwords, and manage group memberships. Proper user and group management ensures secure access control and resource allocation within the system.

Command

Description

Example

passwd

Change or set user password.

passwd user1

Changes the password for user named “user1”.

chpasswd

Change passwords in bulk using a text file.

chpasswd < user_passwords.txt 

Reads passwords from a file and sets them for respective users.

chage

Set aging properties for user passwords (expiration, warning period).

chage -M 90 user1 

Sets maximum password age to 90 days for user “user1”.

useradd

Create a new user account.

useradd -m user2 

Creates a new user “user2” and creates a home directory for them.

usermod

Modify existing user account settings (e.g., change username, home directory, group membership).

usermod -l newuser olduser

Renames user “olduser” to “newuser”.

userdel

Delete a user account.

userdel user2

Deletes the user account “user2”.

groupadd

Create a new group.

groupadd group1

Creates a new group named “group1”.

groupmod

Modify existing group settings (e.g., change group name or GID).

groupmod -n newgroup oldgroup

Renames group “oldgroup” to “newgroup”.

groupdel

Delete a group.

groupdel group1 

Deletes the group named “group1”.

Linux Security Command Cheat Sheet

Maintaining a secure and hardened Linux system is crucial in today’s threat-laden digital landscape. This comprehensive Linux Security Command Cheat Sheet serves as an invaluable resource for system administrators and security professionals, providing a concise reference to essential commands spanning various security domains. From user and group management to privilege escalation, file system security, process monitoring, firewall configuration, and security scanning, this guide covers a wide array of tools and utilities tailored for fortifying Linux environments.

Whether you’re managing access controls, auditing system events, securing network communications, or proactively detecting and mitigating potential threats, this cheat sheet equips you with the necessary knowledge to navigate through the vast arsenal of Linux security commands. With practical examples and clear descriptions, this resource empowers you to effectively secure, harden, and maintain the integrity of your Linux systems, ensuring robust protection against evolving cyber threats.

Linux Security Command Cheat Sheet

  • User and Group Management
  • Privilege Management
  • File and Directory Management
  • Process Management
  • Firewall and Security
  • Networking and Security Tools
  • Security Scanners

Similar Reads

User and Group Management

Managing users and groups is a critical aspect of Linux system administration. These commands allow you to create, modify, and delete user accounts, set passwords, and manage group memberships. Proper user and group management ensures secure access control and resource allocation within the system....

Privilege Management

Privilege management commands enable administrators to temporarily elevate or switch user privileges, granting access to perform administrative tasks or run commands with elevated permissions. Tools like su and sudo facilitate controlled access to restricted operations, providing a secure and auditable way to manage system resources....

File and Directory Management

These commands are essential for managing files and directories on a Linux system. They allow you to change file permissions, ownership, and default access rights, ensuring proper access control and security. Additionally, commands like ls provide a way to list and inspect file system contents and metadata....

Process Management

Monitoring and managing processes is crucial for system administration. These commands provide insights into running processes, their resource usage, and network connections. Tools like ps, top, and lsof help identify and troubleshoot issues related to system performance, resource consumption, and potential security threats....

Firewall and Security

Linux offers various tools for configuring and managing firewalls, intrusion detection and prevention systems, auditing, and security policies. Commands like firewalld, fail2ban, and auditd help secure the system by controlling network traffic, detecting and mitigating malicious activities, and monitoring system events for security purposes....

Networking and Security Tools

These commands encompass a wide range of networking and security-related utilities. From secure remote access with ssh to network scanning with nmap, encryption with openssl and gpg, and data transfer with curl and wget, these tools provide essential capabilities for secure communication, data protection, and network analysis....

Security Scanners

Linux offers several security scanning tools to detect and mitigate potential security threats. Commands like chkrootkit, rkhunter, and lynis are designed to scan the system for rootkits, backdoors, vulnerabilities, and provide hardening recommendations, helping to maintain a secure and hardened system....

Conclusion

In summary, this Linux Security Command Cheat Sheet packs a ton of useful information for securing your Linux systems in one easy-to-reference place. By having these commands at your fingertips, you can properly manage user access, harden file system security, detect threats with scanning tools, and generally batten down the hatches against any potential attacks or vulnerabilities. Make this your go-to guide for keeping your Linux environments safe and secure....