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Attacks by ZmEu or w00tw00t robots

Who is ZmEu?

An image showing ZmeuThe name Zmeu (no capital E) is the name of a fantastic creature of Romania. There are so many stories that there isn't a clear understanding of what it is... but it is human like, can spit fire and wants to marry young women.

If you're wondering, it is generally a bad guy.

ZmEu Attack

Today, I noticed a lot of traffic on one of my servers. Looking into what was happening, I immediately found out that an attacker was looking for a loophole in that system. That attack was being performed from China.

Why are hotmail.com emails blocked by postgrey even though it is whitelisted?

Lately, I received emails from a customer something like 12 hours later...

So I checked closer and could see that the email was from hotmail.com.

Great.

On the server, I edited my whitelist to see what was going on:

vim /etc/postgrey/whitelist_clients.local

Searching the list I could see hotmail.com, so why is it that it gets bounced with a 450 by Postgrey if it is whitelisted?

Looking closer at the logs left behind by Postgrey, I found this line:

Apr 23 06:33:34 m2osw postgrey[1742]: action=greylist,
      reason=new,
      client_name=<secret>.outlook.com,
      ...

SugarCRM Community Edition for Ubuntu 16.04 with PHP 7

As I wanted to use SugarCRM on my new server, I looked into the Community Edition and apparently the company is not willing to convert their code so it works under PHP 7.

So that would not work on a newer system because the code uses quite a few forbidden mechanism (wrong class definitions, old defunct functions...) and that prevents to even instal the system on your machine.

Now, I have looked closer into it and I am getting a version that works pretty darn well already. I still have some issues here and there, but I think you can already make use of that version. Except for one thing which ...

Boot into the command line console in Ubuntu 16.04

As I just upgraded my 14.04 installation to 16.04, it booted right up to lightdm.

I had it properly setup to boot in a console before, but somehow it changed the behavior on me.

This is because the computer is now using systemd to boot.

I already had the GRUB variables setup as expected:

GRUB_CMDLINE_LINUX_DEFAULT="text"
GRUB_CMDLINE_LINUX="text"
GRUB_TERMINAL=console

But this is not enough if you want to start in the console when running systemd (which is running since 15.04).

systemd has a list of variables you can tweak using the systemctl command. To boot in ...

Apache2 error: client denied by server configuration

I installed a website on a brand install installation of Ubuntu 14.04 (opposed to an upgrade from earlier versions) and the same website would not start...

Apache2 would give me the following error:

client denied by server configuration

which did not seem to tell me anything... I search for the error and the first page that popped up was a page by Apache2 and they said to add the deny/allow trick. I tried that and it did not help.

    <Directory /my/special/directory>
        Order allow,deny
        Allow from all
    </Directory>

Search further, I found an answer on ...

How to setup a Linux firewall

Introduction

If you setup a Linux box, you want to setup a firewall before you connect your computer to the Internet. If you are setting up a remote server, it should only have the SSH port open. Connect to it, setup the fire, then only install the other servers and open ports as required (and only ports that need to be connected from the outside.)

Any port that you open without the firewall already setup is at risk. You may want to install PHP and along will come a database which may open a port to the Internet. Something that you just don't want to happen.

Setup Firewall

To ...

Turning sites and modules on and off in Apache2

I always have to looks for the command line option to turn sites and modules on and off (really it is said to be enabled or disabled.)

The commands are as follow:

  • a2ensite -- enable one site
  • a2dissite -- disable one site
  • a2enmod -- enable one module
  • a2dismod -- disable one module

When you use one of the commands in the command line terminal without specifying which site or module to enable, then you are given a list of the sites or modules you can enable or disable. Note that the configuration files have to end with .conf for this mechanism to work as expected.

Lost SSH key graphical prompt and auto-add to SSH agent

At some point in the past, my system somehow lost the ability to avoid asking me for my key every time I connect to one of my servers. It generally okay, I don't do so much work on that server that I'd have to connect all the time...

However, it is annoying when, once in while, I end up doing a lot of work, back and forth.

The ssh-agent was installed and working. I could add the key manually:

ssh-add ~/.ssh/my-secret-key
ssh-add -l

The ssh-add command allows you to add and remove keys from the ssh-agent. The -l command line option lists the keys currently held by the agent.

...

Cannot connect my Host system to Cassandra running on my Guest VM

I found a different way which is to use the:
Local Network or Host-only Network on your Virtual Machine

Today I did my first full install of Snap on a VM in my Ubuntu development system that runs VirtualBox.

This took me about 1h between getting all the files ready from our own APT repository, and then finding out all the setups needed (we have a few working installations, but we added all the necessary magic with time and did not clearly document all the steps yet... argh! so much to do!)

At some point, I wanted to setup the "domains" and "websites" tables on the VM. ...

[ODBC Driver Manager] Data source name not found and no default driver specified

As I was working on a MS-Windows installation, I ran in this weird error: Data source not found and no default driver specified...

This was output when I was running the following in a command line prompt:

osql -E

The result should have been an MSSQL prompt instead!

The problem on the computer was that I uninstalled MSSQL 2005 that was automatically installed by Visual Studio C++ and was not compatible with our application, so I first uninstalled that but that uninstallation is really not proper. It leaves a LOT of things behind.

After that I installed MSSQL 2014 which was reported as ...

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