Thursday, 19 December 2024

Foundations of Cyber Security.

/ work in progress /.


Introduction.

Each year brings more and more of software and devices connected to the Internet. As more of such are connected, system vulnerabilities increase in numbers as well.

There's deficit in numbers of cybersecurity professionals (in Poland alone, there's need for over 15 000 cybersecurity experts), and it seems that this deficit will increase in numbers as years pass.


Red Team vs. Blue Team.

'Red Team Hackers', 'Ethical Hackers', also called: 'Pentesters' focus on finding vulnerabilities in organization's systems, then report and help Blue Team to 'patch the holes'.

Blue Team are Administrators who are installing, configuring, and monitoring antivirus software, intrusion detection systems, and other protective mechanisms on these devices.

This article concerns more about theory and is mostly of interrest for future Blue Team members. It touches only basics, however. Blue Team aspirants should deepen the knowledge using other means as well.

Red Team members are meant to cooperate & communicate with Blue Team, hence why this article should be useful for them as well.


CIA Triad.

C - Confidentiality
    - Ensuring that informations are available only for authorized personnel
I - Integrity
    - Protecting data from unauthorized modification or deletion
A - Availability
    - Ensuring that informations are available for authorized personnel

Methods for Ensuring Confidentiality:
- Security Policy (Categorizing Data as either Confidential or Public,
  and ensuring that only authorized personnel has access to Confidential Data)
- Encryption
- Access Control (Physical and Multifactored Access Control)

Securing a device often comes at the cost of convenience of use. Protected laptop computer, for example, should be still useful and use-conveniet for authorized personnel. So, in practice, security means should not be too excessive. We should not request, for example, 128-characters-long random passwords from users.

Meaning of Integrity:
- Data should be protected from unauthorized modification
- Example attacks on Data Integrity:
  - Modifying company's payments lists
  - Modifying company's webpage conent files
- Might lead to disastrous consequences for a company

Meaning of Availability & Methods for Ensuring Availability:
- Ensuring continuity of work of systems and applications
- Redundancy (extra resources for case of malfunctions)
- Keeping backups (for swift restoration of data and systems in case of malfunction)

Examples & Solutions for Availability Violations:
- DDoS attacks (Resources Overload might cause troubles in accessibility)
- Viral Marketing (Sudden increase in Web Traffic might lead to overloading of
  server resources)
- Solutions:
  - Scalability
  - Load Balancing
  - Firewalls
  - Monitoring

Additional characteristics of CIA model:
- Authentication & Authorization (verifying user's identity and privileges)
- Non-repudiation (provides proof of the origin, authenticity and integrity of data.
  It provides assurance to the sender that its message was delivered, as well as proof
  of the sender's identity to the recipient)
  This way, neither party can deny that a message was sent, received and processed)
- Robustness (ability of a computer system to cope with errors during execution
  and cope with erroneous input)
- Compliance (fulfilling legal and regulatory requirements)
- Privacy (protecting user privacy and personal data)


Cybersecurity as Process - CSF2.0

Overview:
- Cybersecurity should be treated as continuous process, not as single, one-time,
  100% complete solution
- Every day new attacks & hacking techniques appear. Hacking tools are under constant
  development, with time more advanced and more sophisticated hacking tools appear
- There's need for constant updating of security strategies
- Organizations keep deploying new technological solutions. New technologies might
  introduce new vulnerabilities, new security holes

Being ready for incidents:
- Preparation (developing incident reaction plans)
- Detection (swift identification of potential threats)
- Reaction (immediate reaction to appearing incidents)

Process approach to cybersecurity can ensure readiness for action at any moment.

Process approach to cybersecurity can make compliance with legal and industry requirements easier.

Process approach in practice:
- Planning (developing strategies and objectives of cybersecurity)
- Deployment (implementing planned actions & controls)
- Assesment (efficiency analysis of deployed solutions)
- Perfection (constant refinement of security practices)
- Continuity & cyclicity (keep repeating above solutions in cycles)

Elasticity & Adaptation:
- Fast adaptation to appearing threats
- Adaptation to changing technologies & IT architecture
- Adaptation to changing business requirments, to changing organization needs

Integration with business processes (cybersecurity should not be treated as a
separate concern, should a part of business processes):
- Risk Management (integrating cybersecurity with overall risk management)
- Products Development (take cybersecurity into consideration with products'
  lifecycles)
- Customer Service (integrating cybersecurity with customer support practices)

Cyber Security Framework 2.0 (CSF2.0):
- Created & Developed by NIST (National Institute of Standards & Technology in USA)
- Objective: helps with Risk Management in Cybersecurity
- Universality: can be tailored for small or large companies & organizations

CSF Elasticity:
- Elastic: CSF is an elastic tool, not stiff regulation or standard
- Adjustment: can be tailored for specific organization needs
- Pointers: generic approach, with possibility of custom implementation

CSF2.0 Components:
- Core (center of framework, with key functionalities)
- Profile (description of current and target cybersecurity approach)
- Tiers (characteristics of rigors of actions related with risk management)

CSF2.0 Core:
Govern:
- Describes strategy of Risk Management in organization
- 'Surrounds' and manages five other CSF2.0 components
- Includes determining roles & responsibilites, who is responsible for what
- Manages supply chain(s)
- Sets policies related with cybersecurity

Identify (understanding of what we want to protect):
- Understanding (increasing understanding of current risks in cybersecurity)
- Resources Management (identification & management of organization's resources)
- Risk Assesment (analysis & evaluation of potential threats)

Protect:
- Security Tools (deploying proper security tools for risk management)
- Access Control (managing authentication & authorization, and raising
  users' cybersecurity awareness)
- Data Security (protecting organization's sensitive informations)

Detect:
- Monitoring (constant monitoring of systems and networks)
- Analysis (analysis of incidents & anomalies in realtime)
- Alerts (generating alerts of potential security incidents)

Respond:
- Reaction Plan (preparation and deployment of incidents reaction plans)
- Incident Analysis (detailed analysis of detected cybersecurity incident)
- Softening Effects (actions meant for minimizing effects of security incident)
- also: Reporting & Communication

Recover:
- Recovery Plan (executing plan meant for restoring normal functioning)
- Communication (informing interrested parties about recovery processes)
- Post-Incident Analysis (drawing conclusions & refining processes)

CSF2.0 Profiles:
- Current Profile (description of current organization's cybersecurity state)
- Target Profile (description of desired cybersecurity state to achieve)

CSF2.0 Tiers:
Tiers determine how organization approaches and manages risks on the whole, how much of resources are spent for which risks.

Organization should consider how dangerous which risks are, resources available, and possibility of certain solution deployments.

Choice of Tiers for risks depends on organization. Not always higher tiers mean better security. Organization should choose which tiers to assign for what risks, depending on organization's resources and current needs.

Integrating CSF2.0 with overall risk management:
- Balance (treating cybersecurity risks as equal with other risks)
- Integration (including cybersecurity in overall risk management)
- Development (constant development of risk management processes)


Vulnerabilities and Metrics - CVSS.

/ to be done /.


Threat and Threats Modelling.

/ to be done /.


Risk Management.

/ to be done /.


Risk Metrics.

/ to be done /.


Attack & Incident Reaction Plans.

/ to be done /.


Who is Attacker & Attack Types.

/ to be done /.


Sunday, 15 December 2024

Kali Linux Reference for Pentesters.

Pentesters.

Pentesters are ethical hackers who look for vulnerabilities in target system, and report results to company that hired them, and help to patch (fix) found vulnerabilities before criminals use these vulnerabilities earlier.

Pentesters are also called: 'Red Team Hackers'.


Operating Systems for Pentesters.

Beside Kali Linux (successor of the BackTrack Linux), there's Parrot OS, BlackArch Linux, BackBox, probably more as well. All of these are Operating Systems made for Pentesters.

But Kali Linux is industry's standard, widely used OS for Pentesters.


Directory Structure in Kali Linux:

/bin
(binaries)
This directory contains Linux binaries like the cd and ls commands.
/sbin
(system binaries)
This directory holds system binary files that serve as administrative commands (like fdisk).
/bootThis directory contains the Linux bootloader files.
/dev
(devices)
This directory contains the device configuration files (like /dev/null ).
/sysThis is similar to /dev, which contains configurations about devices and drivers.
/etc
(etcetera)
This directory contains all the administration system files (like /etc/passwd shows all the system users in Kali Linux).
/lib
(libraries)
This directory hods the shared libraries for the binaries inside /bin and /sbin.
/proc
(processes)
This directory contains the processes and kernel information files.
/lost+foundAs in the name, this directory contains the files that have been recovered.
/mnt
(mount)
This directory contains the mounted directories (example, a remote file share).
/mediaThis directory holds the removable media mounted directories (like DVD).
/opt
(option)
This directory is used for add‐on software package installation. It is also used when installing software by users (example, hacking tools that you download from GitHub).
/tmp
(temporary)
This is a temporary folder used temporarily, the holdings are wiped after each reboot. The tmp folder is a good place to download our tools for privilege escalation once we got a limited shell.
/usr
(user)
This directory contains many sub-directories. In fact, /usr/share/ is a folder that we need to memorize because most of the tools that we use in Kali Linux (like Nmap, Metasploit, etc.) are stored there, and it also contains the wordlist dictionary files (/usr/share/wordlists).
/homeThis is the home for Kali Linux users (example /home/kali/).
/rootHome directory for root user.
/srv
(serve)
This folder contains some data related to system server functionalities (like data for FTP servers).
/var
(variable)
This folder contains variable data for databases, logs, and websites. For an example, /var/www/html/ contains the files for the Apache2 web server.
/run
(runtime)
This directory holds runtime system data (like currently logged‐in users).


Commands & Important ideas.

Basic Commands:

- pwd: print working directory
- cd: change directory
- sudo: executing commands with root privileges
- ls: listing directory contents
- ls -l: as ls, but more details provided
- ls -a: as ls, but listing all files, not ignoring hidden ones
- man: displaying manual for commands
- man -f: short explaination of a command
- apropos: searching for commands using keywords
- history: displaying used commands history

Search Commands:

- find: detailed search
- locate: fast search using informations stored in database
- which : searching for executable files locations
- whereis: searching for executable files and related files locations

also, updating database for use of 'locate' command can be done using: 'sudo updatedb' command.

File & directory operations:

- touch: creating empty files
- mkdir: creating directories
- rm: removing files and/or directories
- tree: displaying directory tree structure
- cp: copying files and/or directories
- mv: moving files and/or directories
- echo: printing text
- cat: displaying file's contents
- wc -l: counting lines
- sort: sorting content

Streams:

- stdin: standard input (0)
- stdout: standard output (1)
- stderr: standard error (2)

Redirect operators:

- redirecting stdout (overwriting file): 1>
- redirecting stdout (adding to file): 1>>
- passing stdout to another (next) command (pipe): |
- redirecting stdin: <
- redirecting stderr (overwriting file): 2>
- redirecting stderr (adding to file): 2>>

Collecting System Info:

Informations about users:

- whoami: displays current user's name
- id: detailed information about current user & groups
- who: list of logged in users

Informations about system:

- hostname: name of the host
- uname (-a): (detailed) information about operating system
- env: displays all environment variables
- ps (aux): displays list of processes of all users
- top: monitoring processes in realtime

Network informations:

- ifconfig: displays network interfaces & their configurations
- ip addr: displays ip addresses
- netstat: displays network connections
- ss: socket statistics

Informations about devices:

- df -h: disk space usage, printed in 'human-readable' form
- lsblk: block devices list
- lsusb: USB devices list
- lspci: PCI devices list

Linux Text Editors:

Nano:

nano [file_name]: open/create file
Ctrl + G: help
Ctrl + X: exit
Ctrl + /n: move to line n
Ctrl + K: delete line
Ctrl + F: searching

Vim:

vim [file_name]: open file
i: insert text mode
ESC: return to command mode
dd: delete line
yy: copy line
p: paste
/text: search for text
:w: save
:q: exit
:wq or :x: save & exit
:q!: exit without saving
:set number: display lines numbers
vimtutor: interactive tutorial

Privileges:

Basic Privileges:

- r: read
- w: write
- x: execute

Categories:

- user
- group
- others

Main commands:

- chmod: change privileges
- chmod u+w: adding write privileges for file's owner (user)
- chmod g-w: remove write privileges for file's owner's group
- chmod o+x: adding execute privileges for other users
- chmod 644: privileges in octal notation
- chmod 755: standard privileges for directories

Special ('sticky') bits:

- SUID: execute with owner's privileges
- SGID: execute with group's privileges

System files:

- /etc/passwd: informations about users
- /etc/shadow: encrypted passwords
- /etc/group: informations about groups

Users management:

Managing users:

- useradd: creating user
- useradd -m: creating with home directory
- useradd -s: defining default shell
- useradd -g: setting primary group
- usermod: modifying user
- usermod -g: changing primary group
- usermod -aG: adding additional groups
- deluser: deleting user
- deluser --remove-home: removing with home directory

Managing groups:

- addgroup: creating group
- groups: displaying user's groups
- deluser user group: removing user from group

Managing sudo:

- sudo -l: checking sudo privileges
- visudo: safe editing of sudoers
- su: switching user
- passwd: changing password

Configuration files:

- /etc/sudoers: sudo configuration
- /etc/sudoers.d/: additional configuration files

Installing software:

APT (Advanced Package Tool):

- sudo apt update: refreshing packets list
- sudo apt upgrade: upgrades all packages to newest versions
- apt list --upgradable: shows list of available package upgrades
- apt list --installed: shows list of installed packages
- apt search [name]: searching for package
- apt show [name]: details about package
- sudo apt install [name]: installing package
- sudo apt remove [nazwa]: remove package

DPKG:

- dpkg -l: list of installed dpkg packages
- dpkg -l | grep [name]: search within packages

Additional tools:

- git clone [url] - cloning git repository
- pip install [name] - installing python packages

Useful options:

- --only-upgrade: upgrading only specified package
- -y: automatic install confirmation

Processes & services:

Managing processes:

- ps aux: processes list
- ps auxf: processes list displayed in form of tree
- kill [PID]: termination of a process
- kill -9 [PID]: forced termination of a process
- killall [name]: terminating all processes with given name
- jobs: listing background tasks
- fg %[numer]: moving task to foreground
- ctrl + Z: sending process into background
- &: executing process in background

Managing services:

- systemctl list-units --type=service --all: shows services list
- service --status-all: shows status of all services
- systemctl status [service]: detailed status
- systemctl start/stop/restart [service]: service management
- service [service] start/stop/restart: alternative service management
- journalctl -u [service]: service's logs

Monitoring:

- top - monitoring processes in realtime
- ps auxf | grep [name] - searching for processes


Wordlists.

Wordlists can be used, for example:
- for executing dictionary attacks that find passwords,
- for finding file names when we can't just list the containing directory's contents
  (webpage server's directories sometimes deny listing files in these directories).

One of the most popular wordlist is named 'rockyou.txt'.

In Kali Linux it's available in compressed form, in following path:

/usr/share/wordlists/rockyou.txt.gz