Destiny Sisters Royale

Tuesday, April 14, 2020

Linux Command Line Hackery Series - Part 6

Welcome back to Linux Command Line Hackery series, I hope you've enjoyed this series so far and would have learned something (at least a bit). Today we're going to get into user management, that is we are going to learn commands that will help us add and remove users and groups. So bring it on...

Before we get into adding new users to our system lets first talk about a command that will be useful if you are a non-root user.

Command: sudo
Syntax: sudo [options] command
Description: sudo allows a permitted user to execute a command as a superuser or another user.

Since the commands to follow need root privileges, if you are not root then don't forget to prefix these commands with sudo command. And yes you'll need to enter the root password in order to execute any command with sudo as root.

Command: useradd
Syntax: useradd [options] username
Description: this command is used for creating new user but is kinda old school.
Lets try to add a new user to our box.
[Note: I'm performing these commands as root user, you'll need root privileges to add a new user to your box. If you aren't root then you can try these commands by prefixing the sudo command at the very beginning of these command like this sudo useradd joe. You'll be prompted for your root password, enter it and you're good to go]

useradd joe

To verify that this command has really added a user to our box we can look at three files that store a users data on a Linux box, which are:

/etc/passwd -> this file stores information about a user separated by colons in this manner, first is login name, then in past there used to be an encrypted password hash at the second place however since the password hashes were moved to shadow file now it has a cross (x) there, then there is user id, after it is the user's group id, following it is a comment field, then the next field contains users home directory, and at last is the login shell of the user.

/etc/group -> this file stores information about groups, that is id of the group and to which group an user belongs.

/etc/shadow -> this file stores the encrypted password of users.

Using our command line techniques we learned so far lets check out these files and verify if our user has been created:

cat /etc/passwd /etc/group /etc/shadow | grep joe

In the above screenshot you can notice an ! in the /etc/shadow, this means the password of this user has not been set yet. That means we have to set the password of user joe manually, lets do just that.

Command: passwd
Syntax: passwd [options] [username]
Description: this command is used to change the password of user accounts.
Note that this command needs root privileges. So if you are not root then prefix this command with sudo.

passwd joe

After typing this command, you'll be prompted password and then for verifying your password. The password won't show up on the terminal.
Now joe's account is up and running with a password.

The useradd command is a old school command, lets create a new user with a different command which is kinda interactive.

Command: adduser
Syntax: adduser [options] user
Description: adduser command adds a user to the system. It is more friendly front-end to the useradd command.

So lets create a new user with adduser.

adduser jane

as seen in the image it prompts for password, full name and many other things and thus is easy to use.

OK now we know how to create a user its time to create a group which is very easy.

Command: addgroup
Syntax: addgroup [options] groupname
Description: This command is used to create a new group or add an existing user to an existing group.

We create a new group like this

addgroup grownups

So now we have a group called grownups, you can verify it by looking at /etc/group file.
Since joe is not a grownup user yet but jane is we'll add jane to grownups group like this:

addgroup jane grownups

Now jane is the member of grownups.

Its time to learn how to remove a user from our system and how to remove a group from the system, lets get straight to that.

Command: deluser
Syntax: deluser [options] username
Description: remove a user from system.

Lets remove joe from our system

deluser joe

Yes its as easy as that. But remember by default deluser will remove the user without removing the home directory or any other files owned by the user. Removing the home directory can be achieved by using the --remove-home option.

deluser jane --remove-home

Also the --remove-all-files option removes all the files from the system owned by the user (better watch-out). And to create a backup of all the files before deleting use the --backup option.

We don't need grownups group so lets remove it.

Command: delgroup
Syntax: delgroup [options] groupname
Description: remove a group from the system.

To remove grownups group just type:

delgroup grownups

That's it for today hope you got something in your head.

Related word

How To Start | How To Become An Ethical Hacker

Are you tired of reading endless news stories about ethical hacking and not really knowing what that means? Let's change that!

This Post is for the people that:

Have No Experience With Cybersecurity (Ethical Hacking)
Have Limited Experience.
Those That Just Can't Get A Break

OK, let's dive into the post and suggest some ways that you can get ahead in Cybersecurity.

I receive many messages on how to become a hacker. "I'm a beginner in hacking, how should I start?" or "I want to be able to hack my friend's Facebook account" are some of the more frequent queries. Hacking is a skill. And you must remember that if you want to learn hacking solely for the fun of hacking into your friend's Facebook account or email, things will not work out for you. You should decide to learn hacking because of your fascination for technology and your desire to be an expert in computer systems. Its time to change the color of your hat 😀

I've had my good share of Hats. Black, white or sometimes a blackish shade of grey. The darker it gets, the more fun you have.

If you have no experience don't worry. We ALL had to start somewhere, and we ALL needed help to get where we are today. No one is an island and no one is born with all the necessary skills. Period.OK, so you have zero experience and limited skills…my advice in this instance is that you teach yourself some absolute fundamentals.

Let's get this party started.

What is hacking?

Hacking is identifying weakness and vulnerabilities of some system and gaining access with it.

Hacker gets unauthorized access by targeting system while ethical hacker have an official permission in a lawful and legitimate manner to assess the security posture of a target system(s)

There's some types of hackers, a bit of "terminology".
White hat — ethical hacker.
Black hat — classical hacker, get unauthorized access.
Grey hat — person who gets unauthorized access but reveals the weaknesses to the company.
Script kiddie — person with no technical skills just used pre-made tools.
Hacktivist — person who hacks for some idea and leaves some messages. For example strike against copyright.

Skills required to become ethical hacker.

Curosity anf exploration
Operating System
Fundamentals of Networking

*Note this sites

LEGALITY OF ETHICAL HACKING

Why ethical hacking?

Legality of Ehical Hacking

Ethical hacking is legal if the hacker abides by the rules stipulated in above section on the definition of ethical hacking.

Ethical hacking is not legal for black hat hackers.They gain unauthorized access over a computer system or networks for money extortion.

Related links

Hacktronian: All In One Hacking Tools Installer For Linux And Android

Hacktronian Installation
Termux users must install Python and Git first: pkg install git python
Then enter these commands: You can watch the full installation tutorial here:

Hacktronian Menu:

Information Gathering

Password Attacks

Wireless Testing

Exploitation Tools

Sniffing & Spoofing

Web Hacking

Private Web Hacking

Post Exploitation

Install The HACKTRONIAN

Information Gathering menu:

Nmap

SEToolkit

Port Scanning

Host To IP

wordpress user

CMS scanner

XSStrike Dork - Google Dorks Passive Vulnerability Auditor

Scan A server's Users Crips

Password Attacks menu:

Cupp

Ncrack

Wireless Testing menu:

Reaver

PixieWPS

Fluxion

Exploitation Tools menu:

ATSCAN

SQLMap

Shellnoob

commix

FTP Auto Bypass

jboss-autopwn

Sniffing and Spoofing menu:

SEToolkit

SSLtrip

pyPISHER

SMTP Mailer

Web Hacking menu:

Drupal Hacking

Inurlbr

Wordpress & Joomla Scanner

Gravity Form Scanner

File Upload Checker

Wordpress Exploit Scanner

Wordpress Plugins Scanner

Shell and Directory Finder

Joomla! 1.5 - 3.4.5 remote code execution

Vbulletin 5.X remote code execution

BruteX - Automatically brute force all services running on a target

Arachni - Web Application Security Scanner Framework

Private Web Hacking:

Get all websites

Get joomla websites

Get wordpress websites

Control Panel Finder

Zip Files Finder

Upload File Finder

Get server users

SQli Scanner

Ports Scan (range of ports)

ports Scan (common ports)

Get server Info

Bypass Cloudflare

Post Exploitation:

Shell Checker

POET

Weeman

Hacktronian's License: MIT Licence

That's It... If You Like This Repo. Please Share This With Your Friends. And Don't Forget To Follow The Author At Twitter, Instagram, Github & SUBSCRIBE His YouTube Channel!!!

Thank you. Keep Visiting.. Enjoy.!!! :)

Download Hacktronian

More info

$$$ Bug Bounty $$$

What is Bug Bounty ?

A bug bounty program, also called a vulnerability rewards program (VRP), is a crowdsourcing initiative that rewards individuals for discovering and reporting software bugs. Bug bounty programs are often initiated to supplement internal code audits and penetration tests as part of an organization's vulnerability management strategy.

Many software vendors and websites run bug bounty programs, paying out cash rewards to software security researchers and white hat hackers who report software vulnerabilities that have the potential to be exploited. Bug reports must document enough information for for the organization offering the bounty to be able to reproduce the vulnerability. Typically, payment amounts are commensurate with the size of the organization, the difficulty in hacking the system and how much impact on users a bug might have.

Mozilla paid out a $3,000 flat rate bounty for bugs that fit its criteria, while Facebook has given out as much as $20,000 for a single bug report. Google paid Chrome operating system bug reporters a combined $700,000 in 2012 and Microsoft paid UK researcher James Forshaw $100,000 for an attack vulnerability in Windows 8.1. In 2016, Apple announced rewards that max out at $200,000 for a flaw in the iOS secure boot firmware components and up to $50,000 for execution of arbitrary code with kernel privileges or unauthorized iCloud access.

While the use of ethical hackers to find bugs can be very effective, such programs can also be controversial. To limit potential risk, some organizations are offering closed bug bounty programs that require an invitation. Apple, for example, has limited bug bounty participation to few dozen researchers.

More info

Parrot Security OS 4.7 Released With New Linux Kernel, Menu Structure, Tools Improvements And Many Changes

In Sep 18 2019, Parrot Security OS 4.7 has released, with many new following changes below.

Latest Linux 5.2.x series
The new ISO files of Parrot 4.7 are being released only now, but we were the first Debian derivative distribution to introduce Linux 5.1 and 5.2 to all our users, and now ParrotSec team is ready to offer it also with our ISO files rebild cycle to support more devices and integrate all the latest linux features from the beginning.

New sandbox behavior (opt-in rather than opt-out)
Sandboxing is a great thing, and ParrotSec team was in the first line when they introduced our custom Firejail and AppArmor solution for the first time many years ago. We still want to improve such feature and ParrotSec team has a whole team dedicated to improve sandboxing and hardening of the Parrot Security OS system, but ParrotSec team had to face the many users with issues caused by the restrictions of our sandbox.

In Parrot Security OS 4.7 the sandbox is disabled by default, and users can decide wether to start an application sandboxed or not. You can easily start the sandboxed version of an installed program from the /sandbox/ folder or from a dedicated menu that ParrotSec team plans to improve in the future (meanwhile the search feature of the bottom menu will fit all your needs), or you can re-enable it by default by using the firecfg tool.

New menu structure and tools improvements
The pentesting menu structure was refactored and re-designed to make tools easier to access in a more logical hierarchical structure. New tools were also added to the project, and ParrotSec team plans to add even more in the future. Not all of them are going to be pre-installed, but a good set of tools in our repository enables pentesters to build up the perfect pentest system for their specific needs, regardless the default package selection picked by ParrotSec team.

Domain changes
To reflect the neutrality of a distro that started as a pentest-only system and became more general purpose later with Parro Home, the community voted through a democratic process to switch to parrotlinux.org as the new default domain of the project.

ParrotSec team will still use ParrotSec.org for other things (included the old email addresses), and they introduced other project domains to handle specific parts of the infrastructure.

Repository changes
ParrotSec team is preparing to integrate a future LTS branch, so they decided to rename the current repository from stable to rolling. Nothing changes for the end user, and the current Parrot Security OS branch will continue to behave the same as before, but now with a different name to better reflect the rolling release nature of the system, waiting for the LTS edition to join the Parrot Security OS family along side the rolling branch in a similar way OpenSUSE does.

New MATE 1.22 release: Parrot Security OS 4.7 ships with the latest MATE 1.22 desktop environment.

Miscellaneous: New Firefox Browser 69, the latest Radare2 and cutter versions and many other important upgrades are all aboard as expected in a properly developed rolling release distro.

How to upgrade to the lastest Parrot Security OS version
You can update your existing Parrot Security OS system with this command:
sudo parrot-upgrade

Or use the raw apt command

sudo apt update
sudo apt full-upgrade

Don't forget to use this command regularly (at least once a week) to receive the latest security updates and bugfixes from the Parrot Security OS repository.

Or you can download the latest release from official download page.

From Parrot Project Blog

goGetBucket - A Penetration Testing Tool To Enumerate And Analyse Amazon S3 Buckets Owned By A Domain

When performing a recon on a domain - understanding assets they own is very important. AWS S3 bucket permissions have been confused time and time again, and have allowed for the exposure of sensitive material.

What this tool does, is enumerate S3 bucket names using common patterns I have identified during my time bug hunting and pentesting. Permutations are supported on a root domain name using a custom wordlist. I highly recommend the one packaged within AltDNS.

The following information about every bucket found to exist will be returned:

List Permission
Write Permission
Region the Bucket exists in
If the bucket has all access disabled

Installation

go get -u github.com/glen-mac/goGetBucket

Usage
goGetBucket -m ~/tools/altdns/words.txt -d <domain> -o <output> -i <wordlist>

Usage of ./goGetBucket:
  -d string
        Supplied domain name (used with mutation flag)
  -f string
        Path to a testfile (default "/tmp/test.file")
  -i string
        Path to input wordlist to enumerate
  -k string
        Keyword list (used with mutation flag)
  -m string
        Path to mutation wordlist (requires domain flag)
  -o string
        Path to output file to store log
  -t int
        Number of concurrent threads (default 100)

Throughout my use of the tool, I have produced the best results when I feed in a list (-i) of subdomains for a root domain I am interested in. E.G:

www.domain.com
mail.domain.com
dev.domain.com

The test file (-f) is a file that the script will attempt to store in the bucket to test write permissions. So maybe store your contact information and a warning message if this is performed during a bounty?
The keyword list (-k) is concatenated with the root domain name (-d) and the domain without the TLD to permutate using the supplied permuation wordlist (-m).
Be sure not to increase the threads too high (-t) - as the AWS has API rate limiting that will kick in and start giving an undesired return code.

Download goGetBucket

Parrot Security OS 4.7 Released With New Linux Kernel, Menu Structure, Tools Improvements And Many Changes

sudo apt update
sudo apt full-upgrade

From Parrot Project Blog

Related word

Vsftpd Backdoor - Ekoparty Prectf - Amn3S1A Team

It's a 32bits elf binary of some version of vsftpd, where it have been added a backdoor, they don't specify is an authentication backdoor, a special command or other stuff.

I started looking for something weird on the authentication routines, but I didn't found anything significant in a brief period of time, so I decided to do a bindiff, that was the key for locating the backdoor quickly. I do a quick diff of the strings with the command "strings bin | sort -u" and "vimdiff" and noticed that the backdoored binary has the symbol "execl" which is weird because is a call for executing elfs, don't needed for a ftp service, and weird that the compiled binary doesn't has that symbol.

Looking the xrefs of "execl" on IDA I found that code that is a clear backdoor, it create a socket, bind a port and duplicate the stdin, stdout and stderr to the socket and use the execl:

There are one xrefs to this function, the function that decides when trigger that is that kind of systems equations decision:

The backdoor was not on the authentication, it was a special command to trigger the backdoor, which is obfuscated on that systems equation, it was no needed to use a z3 equation solver because is a simple one and I did it by hand.

The equation:

cmd[0] = 69

cmd[1] = 78

cmd[1] + cmd[2] = 154

cmd[2] + cmd[3] = 202

cmd[3] + cmd[4] = 241

cmd[4] + cmd[5] = 233

cmd[5] + cmd[6] = 217

cmd[6] + cmd[7] = 218

cmd[7] + cmd[8] = 228

cmd[8] + cmd[9] = 212

cmd[9] + cmd[10] = 195

cmd[10] + cmd[11] = 195

cmd[11] + cmd[12] = 201

cmd[12] + cmd[13] = 207

cmd[13] + cmd[14] = 203

cmd[14] + cmd[15] = 215

cmd[15] + cmd[16] = 235

cmd[16] + cmd[17] = 242

The solution:

cmd[0] = 69

cmd[1] = 75

cmd[2] = 79

cmd[3] = 123

cmd[4] = 118

cmd[5] = 115

cmd[6] = 102

cmd[7] = 116

cmd[8] = 112

cmd[9] = 100

cmd[10] = 95

cmd[11] = 100

cmd[12] = 101

cmd[13] = 106

cmd[14] = 97

cmd[15] = 118

cmd[16] = 117

cmd[17] = 125

The flag:

EKO{vsftpd_dejavu}

The binary:
https://ctf.ekoparty.org/static/pre-ekoparty/backdoor

More articles

Destiny Sisters Royale

Tuesday, April 14, 2020

Linux Command Line Hackery Series - Part 6

Related word

How To Start | How To Become An Ethical Hacker

Related articles

LEGALITY OF ETHICAL HACKING

Related links

Hacktronian: All In One Hacking Tools Installer For Linux And Android

$$$ Bug Bounty $$$

Parrot Security OS 4.7 Released With New Linux Kernel, Menu Structure, Tools Improvements And Many Changes

Read more

goGetBucket - A Penetration Testing Tool To Enumerate And Analyse Amazon S3 Buckets Owned By A Domain

Related links

Parrot Security OS 4.7 Released With New Linux Kernel, Menu Structure, Tools Improvements And Many Changes

Related word

Vsftpd Backdoor - Ekoparty Prectf - Amn3S1A Team

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