High-Risk Linux Server Commands: A Comprehensive Security Guide

Introduction: The Risks of Server Operations

In the realm of large-scale operations management, system administrators frequently utilize powerful commands to maintain infrastructure. However, specific commands pose significant risks if mishandled. Common examples include rm -rf, reboot, and mkfs.

If these high-risk commands are executed accidentally or incorrectly, the consequences can be severe, ranging from critical data loss and service interruptions to compromising the overall stability of business systems. Therefore, effective management and awareness of these commands are essential for maintaining system security.

The Solution: Awareness and Command Filtering

To mitigate these risks, administrators must first be aware of which commands are dangerous. Furthermore, utilizing tools like the JumpServer Command Filter feature can effectively prevent inadvertent operations, significantly enhancing system security.

Below is a categorized summary of common high-risk commands that require caution during daily operations.

1. Common High-Risk Commands

These are frequently used commands that can immediately disrupt system availability or destroy data.

Command	Description
rm	Stands for "remove"; deletes one or more files or directories.
rmdir	Stands for "remove empty directories"; deletes empty directories.
chattr	Changes file attributes.
su	Switches user identity.
visudo	Edits the /etc/sudoers file specifically.
sudo	Executes commands as another user (default is root) allowed in the sudoers file.
shutdown / halt	Shuts down the system.
poweroff	Powers off the machine.
init 0	Switches to runlevel 0, shutting down the system.
reboot	Restarts the system.
init 6	Restarts the system.

2. Disk and File System Management

Commands in this category modify the storage structure. Misuse can lead to the loss of entire file systems.

Command	Description
mount	Mount the file system.
unmount	Unmount the file system.
fdisk	Disk partitioning command, suitable for disks under 2TB.
parted	Disk partitioning command, no size limit.
mkfs	Format and create a Linux file system.
mkswap	Create a Linux swap partition.
swapon	Enable the swap partition.
swapoff	Disable the swap partition.

3. System User Management

Improper use of these commands can lock users out of the system or create security vulnerabilities.

Command	Description
useradd/adduser	Add a user.
usermod	Modify an existing user's properties.
userdel	Delete a user.
passwd	Change user password.
groupadd	Add a user group.
groupdel	Delete a user group.
chage	Modify user password expiration date.

4. System Permissions and Authorization

These commands control access levels. Incorrect settings can expose sensitive files to unauthorized users.

Command	Description
ifup	Start the network interface.
ifdown	Shut down the network interface.
nmtui	Modify network-related information.
vi /etc/sysconfig/network-scripts/ifcfg-*	Edit network-related information.

5. Network Interface Configuration

Modifying network settings remotely carries the risk of disconnecting the administrator from the server.

Command	Description
chmod	Modify the access permissions of files or directories.
chown	Change the owner of files or directories.
chgrp	Change the group ownership of files or directories.
sudo	Execute commands as another user (default is root).
setfacl	Set the access control list (ACL) for files.
getfacl	Get the access control list (ACL) for files.
usermod	Modify the attributes and permissions of existing users.

6. Process Management and Built-in Commands

Terminating critical processes can cause immediate service failure.

Command	Description
alias	Set system alias.
unalias	Cancel system alias.
history	View command execution history.
export	Set or display environment variables.
unset	Delete variables or functions.
kill	Terminate processes.
killall / pkill	Terminate processes by process name.

Conclusion

Understanding these commands is the first step in server security. For robust protection, consider implementing JumpServer to manage user sessions and enforce command filtering policies, ensuring that high-risk commands are monitored or blocked before they cause damage