Feed your firewalls

So as a few of you know I’m this crusty old Sys Admin dude. I have a number of machines that I look after, and they are nearly all Linux machines. They are on pretty much twenty four seven, this site is an example of such an endeavor.

But the internet has a problem – it’s the continual attack on any machine (Mac, Windows Linux, Unix or something else) and any service that said machine might be running.

It’s not uncommon for someone to attempt to attack this machine every day. Probably the worst I’ve seen is about 30 thousand attempts in one day. Typically it’s about 1- 3 K,  and I have been whittling this number down …  there is a way to manage this.

1 Record what the offensive ip address are (auth log is your friend in this instance)
2 Add these offensive address to the firewall “or better” so that they will not ever have any access, even if it to just rattle the locks on the doors of your computers.

Typically the command, to block an ip address is something like this, it’s not a complex thing .

sudo iptables -A INPUT -s 10.1.1.1/32 -j DROP

People are concerned that one may block out legitimate traffic (and admittedly this is important, especially if you do accidentally add your own ip address!…. do you have physical access to the machine? a plan B?).  But don’t let me scare you, what I’m talking about is not complex (just take care!).

When you think about it there are 4,294,967,296 usable version 4 ip address. My current block list on this small machine is about 880 of these…. that is about 0.0000204891% of all available ip v4 address. It’s not much and my machine is rather low tech.

But the problem is routers. My own network is based on a router that is controlled by my isp. I don’t really have total control over this machine, but it would be good if I could manage that process a bit. But the isp says no – you can have 3 settings!

The up shot is, if I’m serious about security and running may own server from home … I have to manage the abuse from a machine level or add an additional router! ?

It would be better to manage it from a router level because then every machine behind that router / firewall would be protected. But we haven’t really made this jump. I also understand that segmenting the internet is not a good thing but I’m happy with my 0.0000204891 % reduction. I don’t feel bad about this.

 

 

Long pass phrases!

Yarn bike

Don’t use a pass word! Use a pass phrase . Twelve or more letters, the odd number and lower and upper case letters, make it something you can remember but long and easy for you to remember is the most important thing.

For example I like dogs, bentley cars and pingpong I might write a sticky note that says
*_*
Fave animal
Fave car
Fave sport

and the pass phrase might look like

Dog*_*bentley*_*pingpong

This is a good pass phrase
But think of it like this

To quote From the TheGreatContini who posts on stackoverflow.
While discusing “How long to brute force 16 character secret key

There are 62 possibilities for each character, and 16 characters. This translates to 62^16 (47672401706823533450263330816) trials worse case, or half of that on average. If the attacker can do a billion trials per second, that means 47672401706823533450 seconds, which is about 1511681941489 years. I think that’s pretty good protection. You could even chop off a few characters and still feel pretty safe.

Probably best not to put your exact pass phrase in this (just in case some one nasty sniffs if across the net work or the interweb) but have a play with this site it’s fun and gets the point home.

The other thing is don’t use the same pass phrase for all accounts!
What you might say do I have to remember lots of pass phrases? Well the next thing to do is start using the keychain, but I’ll talk more about this in another exciting episode!

Have fun and be safe on the interwebs

Quick shout out dumpNotificationDB.py

Had a quick look at this today and it’s a doozy! Patrick Wardle has created a small python script that dumps the data from the macOS, notifications database. This is a whole lot of information that you may not want anyone to see, let alone audit. Be interesting if and how the Mac os X dev team may manage this issue.

More info hear…

https://www.patreon.com/posts/18714633