kubelogin is a client-go credential (exec) plugin implementing azure authentication. This plugin provides features that are not available in kubectl. It is supported on kubectl v1.11+ and you can bypass interactive authentication with it. This means that you do not have to enter a device code login when interacting with AKS.
I had to use the tool for managed identity authentication with Kubernetes service. In the documentation you can find instructions on how to use it for cases like user login, service principal, managed identity.
DevSecOps practices are important for organizations especially when it comes to code repositories. Your code should avoid hard coded passwords and secrets for many reasons as a leak may occur. In this guide I will examine how you can massively scan Azure DevOps repositories for security leaks as passwords and secrets with gitleaks utility.
It was a nice morning when I woke up and started surfing before going to work. Little did I know for what will happen that day. Outlook sent me a notification email, the one you can see below. At first I got shocked. I understood immediately that it was a spam email asking for money through crypto payments, but how did the sent it from my email address? The sender was me and the recipient was also me.
If you check carefully the email originator is the same email as the recipient. Did I got hacked? I instantly went to change my passwords and enable MFA option (yes you should do that before you get p0wned).
After contacting my host provider for logs (I wanted to make sure that the mail server was not affected) I started investigating the email. At first it seems like a normal one. By investigating further, I checked the headers.
Oups something seems strange here. The received from headers point an unknown host, the one that tried to trick me. Mister I could send you back the same email from your own address.
Return-Path: <support@brightdirectories.com>
X-Original-To: webmaster@geralexgr.com
Delivered-To: webmaster@geralexgr.com
Received: from cloudvpsserver.host.brightdirectories.com (unknown [64.91.244.139])
spf=pass (sender IP is 64.91.244.139) smtp.mailfrom=support@brightdirectories.com smtp.helo=cloudvpsserver.host.brightdirectories.com
This method of attack is called spoofing and you can read more details from the below article.
Lets try to implement the same attack now, to understand how difficult this could be. The only thing that you will need is a linux machine running postfix and sendmail package. As simple as that and you become a spoofing hacker.
First things first, install and start postfix service.
The attempt failed. What happened though? By checking the logs, I could find that mail server blocks some incoming messages based on spamhaus service.
Is that hard to bypass? Totally not. You have to go on spamhaus link and whitelist your IP address. The next time the service is updated, your email will be received from the mail server. I have to say that more advanced mail services like google, outlook provide much more sophisticated services to block spam than spamhaus.
By trying to send again my email, I successfully spammed my own mailbox. Lets try a google account this time. I will try to send an email from my personal domain account email to my gmail account. However this would be a spam email as the origin will be a local postfix service that tries to impersonate the real owner.
sendmail -v my_Gmail < mail.txt
You can find my mail.txt contents below.
From: webmaster@blablabla.com
Subject: spoofing email attack this email was sent from an unknown sender using postfix
Voila. I received a spam email from a sender that is not the original one.
If you check more carefully, google adds a question mark and informs you that it could not verify the owner of the email. However the spam went directly to my mailbox and did not arrive on spam.
If you check the headers again, you will verify that the originator is fake
Original Message
Message ID <202111202159.1AKLxI8x016745@geralexgr.com>
Created at: Sat, Nov 20, 2021 at 11:59 PM (Delivered after 2 seconds)
From: webmaster@blablabla.com
To:
Subject: spoofing email attack this email was sent from an unknown sender using postfix
SPF: FAIL with IP 2.84.53.88 Learn more
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Delivered-To:
Received: by 2
Received: from geralexgr.com (IP_address.
Received-SPF: fail (google.com: domain of root@geralexgr.com does not designate IP as permitted sender) client-ip=xxxxxx;
Authentication-Results: mx.google.com;
spf=fail (google.com: domain of root@geralexgr.com does not designate 2.84.53.88 as permitted sender) smtp.mailfrom=root@geralexgr.com
Received: from geralexgr.com (localhost [127.0.0.1]) by geralexgr.com (Postfix) with ESMTPS id 88E031099F6B for <xxxxxx>; Sat, 20 Nov 2021 23:59:18 +0200 (EET)
Received: (from root@localhost) by geralexgr.com (8.15.2/8.15.2/Submit) Sat, 20 Nov 2021 23:59:18 +0200
Date: Sat, 20 Nov 2021 23:59:18 +0200
Message-Id: <202111202159.1AKLxI8x016745@geralexgr.com>
From: webmaster@geralexgr.com
Subject: spoofing email attack this email was sent from an unknown sender using postfix
As you can see from headers, the real sender is root@localhost and not the sender that is shown on gmail. You can also locate the incoming IP address.
To conclude we examined how one could spoof your email account and impersonate your self. Be very careful on the emails you receive and double check the originator. It is very easy to get hacked with this technique.
Sudo and su are two powerful utilities on linux operating system that enables one to manipulate who is performing actions on the filesystem and with which privileges .
The main difference between those two tools is that if administrator uses su - username then he should provide the user password in order to switch to the end user rights. On the other hand with sudo command the administrator should use its own password in order to validate with the system that he wants to run as a superuser the command su - .
As a result by using sudo su - x you dont have to specify the end user password but your own password.
Another way you can authorize your self as superuser is with sudo -i so you do not have to provide the password of root in the system.
The sudo command is very powerful and useful in the linux systems because for security purposes many times you could find root user deactivated and each user has its own credentials and rights. Also actions performed with sudo commands are logged in the operating system.
The most important prerequisite in order to use sudo command in Red Hat or Centos Linux is to be a member of the wheel group. You can give a specific user sudo rights with the following:
Create a new file under /etc/sudoers.d/USERNAME
touch /etc/sudoers.d/operator
and then vi the operator file and add the following line:
operator ALL=(ALL) ALL
using sudo with a user that does not have admin rights.using sudo after creating the necessary file under sudoers.d
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