users in shadow file explanation

this article explain the /etc/shadow

this file content the users information

example of the user data

username -> n1x
password -> $6$UoDmVdoW$tYQQm5uHgOpeEKPygIaQ1GM/0IBbdYVrLHu8ZYF5pT17D3VM.FFKa2wS8J6gqbGKC2IpgImXy7SYVJK9r/fdw.
last date password update since 1970-1-1 -> 16631

you can calculate it simply in python

minmum password age -> 7
maximum password age -> 15
warning days -> 2
inactive days -> 14
expiration date -> 16819

we can list or modify a user by a chage command
example

for setting default config for all users you can use /etc/login.defs

# Password aging controls:
#
# PASS_MAX_DAYS Maximum number of days a password may be used.
# PASS_MIN_DAYS Minimum number of days allowed between password changes.
# PASS_MIN_LEN Minimum acceptable password length.
# PASS_WARN_AGE Number of days warning given before a password expires.
#
PASS_MAX_DAYS 30
PASS_MIN_DAYS 10
PASS_MIN_LEN 10
PASS_WARN_AGE 1

AIDE : Intrusion Detection Environment

this article about Intrusion Detection for file system changes like modification changing owner extra , for critical files or directories in our environment

we using a software called AIDE

Advanced Intrusion Detections Environment
this software base on library called mhash this lib used to calculate file hashes
and AIDE save the file info inside db with base64 formate
the information that will be saved depends on the aide configuration file

example of default info for the linux image file

lets decode this Continue reading AIDE : Intrusion Detection Environment

umask permissions explanation

what is umask ?
umask is the default permissions for writing file in system

where the settings for umask ?
1 – /etc/profile
2 – /etc/bashrc

Continue reading umask permissions explanation

removable disk could lead to privilege escalation

privilege escalation linux with flash disk

removable media with setUID , setGID files could gives privilege escalation
example copy nice command to ur flash storage and ask ur friend to print files in his system then run the command
nice like

it will say root

problem occurs from mounted partition without noexec,nosuid parameter

enjoy ur automount

and

happy hacking 😉

Persistent mount for luks with unlock Key

creating a encrypted disk with luks

our  lil problem here to mount a encrypted disk  automatically  on boot

so no need to enter the pass for mounting but this risky if the machine theft happen because we will use a key inside the system and it will be leaked if our machine stolen

so lets do it first we have to create a key and add it  our partition

to create a key

don’t forget it to set key permission to be 600

Continue reading Persistent mount for luks with unlock Key

Linux Disk Encryption with luks

today we going to make a encrypted disk partition

list prepare our partition

i have a new disk in  /dev/sdb

i will create a partition 100 on it with fdisk

Continue reading Linux Disk Encryption with luks