Disable Firewire in Centos 7

Open the file /etc/modprobe.d/blacklist
* Don’t worry if the file is empty just populate it!

# nano /etc/modprobe.d/blacklist


# sudo nano /etc/modproble.d/blacklist

~ add these lines:

blacklist firewire_core
blacklist firewire_ohci

Save and Reboot!

Install SysStat to enable system monitoring

Install SysStat
# yum -y install sysstat
# systemctl start sysstat
# systemctl enable sysstat

Check the status of SysStat
# systemctl status sysstat

Add SysStat into a Cron Job
# cat /etc/cron.d/sysstat

# Run system activity accounting tool every 10 minutes
*/10 * * * * root /usr/lib64/sa/sa1 1 1
# 0 * * * * root /usr/lib64/sa/sa1 600 6 &
# Generate a daily summary of process accounting at 23:53
53 23 * * * root /usr/lib64/sa/sa2 -A

Settings of SysStat


# sysstat-10.1.5 configuration file.

# How long to keep log files (in days).
# If value is greater than 28, then log files are kept in
# multiple directories, one for each month.


# Compress (using gzip or bzip2) sa and sar files older than (in days):


# Parameters for the system activity data collector
# which are used for the generation of log files

# *note


# *note : valid options

INT     ⇒  System Interrupts
DISK    ⇒  Block Devices
SNMP    ⇒  SNMP statistics
IPV6    ⇒  IPv6 statistics
POWER   ⇒  Power Management statistics
ALL     ⇒  All of the above
XDISK   ⇒  DISK + Partition statistics
XALL    ⇒  All of the above (ALL + XDISK)

Setup psacct to Monitor User Activity in Linux

It is very important to know what are the activities for applications and users in linux operating system. This will be very useful in later time or in case of problems. For this purpose, i would recommend psacct tools to be install. psacct is a free monitoring program to monitor users and applications activity on linux server. This program will display how long user accessing the server, what command are they issuing, how many processes and display logs for commands.

If you are runninng Linux CentOS or Redhat, you should use the following command to install pssacct :

[root@test ~]# yum install psacct -y

By default psacct is disabled on Linux. We should manually start it :

[root@test ~]# systemctl start psacct

To enable psacct on your next reboot use the following command :

[root@test ~]# systemctl enable psacct

Check the status of psacct

[root@test ~]# systemctl status psacct

Other usage from that come in psacct or acct package :

ac command prints the statistics of user logins/logouts (connect time) in hours.
lastcomm command prints the information of previously executed commands of user.
accton commands is used to turn on/off process for accounting.
sa command summarizes information of previously executed commands.
last and lastb commands show listing of last logged in users.

Auditd service

Reload systemd daemon to reload changes made in auditd service unit file:

systemctl daemon-reload

Restart the auditd service: service auditd restart


## Remove any existing rules

## Buffer Size
## Feel free to increase this if the machine panic's
-b 8192

## Failure Mode
## Possible values are 0 (silent), 1 (printk, print a failure message),
## and 2 (panic, halt the system).
-f 1

## Audit the audit logs.
## successful and unsuccessful attempts to read information from the
## audit records; all modifications to the audit trail
-w /var/log/audit/ -k auditlog

## Auditd configuration
## modifications to audit configuration that occur while the audit
## collection functions are operating.
-w /etc/audit/ -p wa -k auditconfig
-w /etc/libaudit.conf -p wa -k auditconfig
-w /etc/audisp/ -p wa -k audispconfig

## Monitor for use of audit management tools
-w /sbin/auditctl -p x -k audittools
-w /sbin/auditd -p x -k audittools

## special files
-a exit,always -F arch=b32 -S mknod -S mknodat -k specialfiles
-a exit,always -F arch=b64 -S mknod -S mknodat -k specialfiles

## Mount operations
-a exit,always -F arch=b32 -S mount -S umount -S umount2 -k mount
-a exit,always -F arch=b64 -S mount -S umount2 -k mount

## changes to the time
-a exit,always -F arch=b32 -S adjtimex -S settimeofday -S stime -S clock_settime -k time
-a exit,always -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k time

## Use stunnel
-w /usr/sbin/stunnel -p x -k stunnel

## cron configuration & scheduled jobs
-w /etc/cron.allow -p wa -k cron
-w /etc/cron.deny -p wa -k cron
-w /etc/cron.d/ -p wa -k cron
-w /etc/cron.daily/ -p wa -k cron
-w /etc/cron.hourly/ -p wa -k cron
-w /etc/cron.monthly/ -p wa -k cron
-w /etc/cron.weekly/ -p wa -k cron
-w /etc/crontab -p wa -k cron
-w /var/spool/cron/crontabs/ -k cron

## user, group, password databases
-w /etc/group -p wa -k etcgroup
-w /etc/passwd -p wa -k etcpasswd
-w /etc/gshadow -k etcgroup
-w /etc/shadow -k etcpasswd
-w /etc/security/opasswd -k opasswd

## monitor usage of passwd
-w /usr/bin/passwd -p x -k passwd_modification

#Monitor for use of tools to change group identifiers
-w /usr/sbin/groupadd -p x -k group_modification
-w /usr/sbin/groupmod -p x -k group_modification
-w /usr/sbin/addgroup -p x -k group_modification
-w /usr/sbin/useradd -p x -k user_modification
-w /usr/sbin/usermod -p x -k user_modification
-w /usr/sbin/adduser -p x -k user_modification

## login configuration and information
-w /etc/login.defs -p wa -k login
-w /etc/securetty -p wa -k login
-w /var/log/faillog -p wa -k login
-w /var/log/lastlog -p wa -k login
-w /var/log/tallylog -p wa -k login

## network configuration
-w /etc/hosts -p wa -k hosts
-w /etc/network/ -p wa -k network

## system startup scripts
-w /etc/inittab -p wa -k init
-w /etc/init.d/ -p wa -k init
-w /etc/init/ -p wa -k init

## library search paths
-w /etc/ld.so.conf -p wa -k libpath

## local time zone
-w /etc/localtime -p wa -k localtime

## kernel parameters
-w /etc/sysctl.conf -p wa -k sysctl

## modprobe configuration
-w /etc/modprobe.conf -p wa -k modprobe

## pam configuration
-w /etc/pam.d/ -p wa -k pam
-w /etc/security/limits.conf -p wa  -k pam
-w /etc/security/pam_env.conf -p wa -k pam
-w /etc/security/namespace.conf -p wa -k pam
-w /etc/security/namespace.init -p wa -k pam

## GDS specific secrets
-w /etc/puppet/ssl -p wa -k puppet_ssl

## postfix configuration
-w /etc/aliases -p wa -k mail
-w /etc/postfix/ -p wa -k mail

## ssh configuration
-w /etc/ssh/sshd_config -k sshd

## changes to hostname
-a exit,always -F arch=b32 -S sethostname -k hostname
-a exit,always -F arch=b64 -S sethostname -k hostname

## changes to issue
-w /etc/issue -p wa -k etcissue
-w /etc/issue.net -p wa -k etcissue

## this was to noisy currently.
# log all commands executed by an effective id of 0 aka root.
-a exit,always -F arch=b64 -F euid=0 -S execve -k rootcmd
-a exit,always -F arch=b32 -F euid=0 -S execve -k rootcmd

## Capture all failures to access on critical elements
-a exit,always -F arch=b64 -S open -F dir=/etc -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/bin -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/sbin -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/usr/bin -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/usr/sbin -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/var -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/home -F success=0 -k unauthedfileacess
-a exit,always -F arch=b64 -S open -F dir=/srv -F success=0 -k unauthedfileacess

## Monitor for use of process ID change (switching accounts) applications
-w /bin/su -p x -k priv_esc
-w /usr/bin/sudo -p x -k priv_esc
-w /etc/sudoers -p rw -k priv_esc

## Monitor usage of commands to change power state
-w /sbin/shutdown -p x -k power
-w /sbin/poweroff -p x -k power
-w /sbin/reboot -p x -k power
-w /sbin/halt -p x -k power

## Make the configuration immutable
-e 2

P.S After a reboot, total crash with auditd, IP internal Conflict ! and total CSF block! Good luck with this one!

How to find Hardware information on Live (running) Servers & Systems

dmidecode is a tool for dumping a computer DMI (some say SMBIOS) table contents in a human-readable format. This table contains a description of the system hardware components, as well as other useful pieces of information such as serial numbers  and  BIOS  revision.  You can retrieve this information without having to probe for the actual hardware.  While this is a good point in terms of report speed and safeness, this also makes the presented information possibly unreliable.

The  DMI  table  does not  only describe what the system is currently made of, it also can report the possible evolutions (such as the fastest supported CPU or the maximal amount of memory supported).

SMBIOS stands for System Management BIOS, while DMI stands for Desktop Management Interface. Both standards are  tightly related and developed by the DMTF (Desktop Management Task Force).

# yum install dmidecode

# dmidecode –type bios [About BIOS Details]

# dmidecode –type system [About System Information]

# dmidecode –type baseboard [About NIC & Storage Card]

# dmidecode –type chassis [About Chassis Information]

# dmidecode –type processor [About Processor Information]

# dmidecode –type memory [About Memory Information]

# dmidecode –type cache [About Cache Information]

# dmidecode –type connector [About USB Information]

# dmidecode –type slot [About Slot Information]

How to read or view utmp, wtmp and btmp files in Linux

In Linux operating systems everything is logged some where. Most of the system logs are logged in to /var/log folder. This folder contains logs related to different services and applications. In this folder we have some files such as utmp, wtmp and btmp. These files contains all the details about login’s and logout’s which are from local as well as from remote systems and system status such as uptime etc.

utmp will give you complete picture of users logins at which terminals, logouts, system events and current status of the system, system boot time (used by uptime) etc.

wtmp gives historical data of utmp.

btmp records only failed login attempts.

Provide how logged in, when they logged in and when they logged out
# last

To open wtmp file and view its content use blow command
# last -f /var/log/wtmp

To see still logged in users view utmp file use last command
# last -f /var/run/utmp

To view btmp file use same command
# last -f /var/log/btmp

Disable USB Devices Hardening Centos 7

We would like to disable all USB devices connected to our HP Red Hat Linux based workstations. I would like to disable USB flash or hard drives, which users can use with physical access to a system to quickly copy sensitive data from it. How do I disable USB device support under CentOS Linux, RHEL version 5.x/6.x/7.x and Fedora latest version?

The USB storage drive automatically detects USB flash or hard drives. You can quickly force and disable USB storage devices under any Linux distribution. The modprobe program used for automatic kernel module loading. It can be configured not load the USB storage driver upon demand. This will prevent the modprobe program from loading the usb-storage module, but will not prevent root (or another privileged program) from using the insmod/modprobe program to load the module manually. USB sticks containing harmful malware may be used to steal your personal data. It is not uncommon for USB sticks to be used to carry and transmit destructive malware and viruses to computers. The attacker can target MS-Windows, macOS (OS X), Android and Linux based system.

usb-storage driver

The usb-storage.ko is the USB Mass Storage driver for Linux operating system. You can see the file by typing the following command:
# ls -l /lib/modules/$(uname -r)/kernel/drivers/usb/storage/usb-storage.ko

All you have to do is disable or remove the usb-storage.ko driver to restrict to use USB devices on Linux such as:

  1. USB keyboards
  2. USB mice
  3. USB pen drive
  4. USB hard disk
  5. Other USB block storage

BIOS option

You can also disable USB from system BIOS configuration option. Make sure BIOS is password protected. This is recommended option so that nobody can boot it from USB.


In linux it’s even more easily done, by unloading the usb_storage module: for disable :-

# modprobe -r usb_storage

for enable :-

# modprobe -i usb_storage

The easiest way to disable usb storage device in linux is create following file And add following line inside the file

# touch /etc/modprobe.d/no-usb

install usb-storage /bin/true