Ask HN: I finally ditched Windows for Ubuntu - How do I keep things secure?

https://news.ycombinator.com/item?id=5501191

by wikiburner • 13 years ago

13 12 13 years ago

news.ycombinator.com

I'm a Python programmer who finally got fed up enough with Windows to take the plunge.

The thing is I'm totally new to Linux, and am pretty paranoid about security (former Win user, remember.) I really feel like I'm flying blind here.

I know the standard, glib line is that you don't have to worry about security once you leave Microsoft, but I have a hard time accepting that. It seems like I should be installing Anti-virus, anti-malware, and firewall software.

Does anyone know of any basic intros to Linux/Ubuntu security, or have any tips?

Thanks in advance.

t0• 13 years ago

Iptables to block most ports. In general you don't have anything to worry about. Malware makers simply aren't targeting linux.

Glyptodon• 13 years ago

Ubuntu also has an 'easy' tool called UFW (uncomplicated firewall?) to configure basic firewall rules and such. It's probably a lot easier to use than Iptables if you just want to make some basic rules.

Unless you're hosting an SSH server or something I don't think there's much to do out of the box for desktop Ubuntu.

sherril8• 13 years ago

I found this article to be of some help: http://www.andrewault.net/2010/05/17/securing-an-ubuntu-serv...

To start, you will just need to set up IPTables and Fail2Ban.

caw• 13 years ago

That sort of stuff is really only necessary if on your home network you're doing port passthroughs or if this machine is directly connected to the internet with a public IP. For most users behind a router, you don't really need fail2ban and iptables.

pasbesoin• 13 years ago

Caveat: I haven't read the article linked in the GP, yet. (I will.) But the comments here immediately elicit this thought:

How many users have a laptop that they are connecting to one or another undefined (to them) form of "public" wifi? (And/or to someone else's internal network that may be compromised.)

desas• 13 years ago

Even then, out of the box, the only services listening to ports are dhcp and mdns.

notaddicted• 13 years ago

I am not sophisticated enough to critically assess these documents, but here are two sources:

For a basic overview of Linux security: Red Hat Enterprise Linux 6 Security Guide

https://access.redhat.com/site/documentation/en-US/Red_Hat_E...

Here is a blog post by someone who is protecting his laptop, for each security measure he says what and why:

https://grepular.com/Protecting_a_Laptop_from_Simple_and_Sop...

HN Discussion:

https://news.ycombinator.com/item?id=4018426

jerrac• 13 years ago

https://help.ubuntu.com/community/Security

lifeisstillgood• 13 years ago

This is a pretty good question - mostly because the heart of good security, good airline safety and good surgery is a checklist.

And I don't think I have a checklist thats uptodate, even the one in my head.

ShowHN: using HN as my personal todo list cos I actually look at my threads list daily...

https://grepular.com/Protecting_a_Laptop_from_Simple_and_Sop...

https://help.ubuntu.com/community/Security

https://news.ycombinator.com/item?id=4018426

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/fi...

http://www.freebsd.org/doc/handbook/security.html

That site on secondary GPGkeys I keep failing to find

bdunbar• 13 years ago

My 02 cents, you need to worry about security, but it's more like wearing seatbelts on a sunny day. The odds you'll need them are remote, as long as you exercise care and diligence.

When you're running an MS system, I guess the analogy would be you're driving in a demolition derby. It's not 'if' you'll get hit but when ...

- Turn services off you don't need or use.

- Delete services you will never use.

- Firewall with iptables.

- Setup SSH to disallow login for root. Or turn SSH off if you won't login into it from another host. You can always _start_ SSH again if you need it.

GaryGapinski• 13 years ago

Start with (as root)

    apt-get install openssh-server
    apt-get install fail2ban
    ufw allow OpenSSH
    ufw enable

I use the following suffix to the /etc/ssh/sshd_config file:

    …
    72	#
    73	# local tweaks
    74	#
    75	Protocol 2
    76	PermitRootLogin no
    77	Banner /etc/ssh/banner
    78	UseDNS yes
    79	MaxStartups 1
    80	LoginGraceTime 15
    81	PubkeyAuthentication yes
    82	PasswordAuthentication no
    83	ChallengeResponseAuthentication no
    84	X11Forwarding yes
    85	AllowTcpForwarding yes
    86	DebianBanner no

    87	Match Address 192.168.0.0/24,127.0.0.1,192.168.1.0/24
    88	PasswordAuthentication yes

Line 82 should be commented out until you have generated an SSH key pair and placed the public key in ~/.ssh/authorized_keys, as it prevents logins using just a password. Lines 87-88 remove this restriction for local nets. Line 77 references a banner that you can provide which is presented upon SSH connection.

fail2ban with its default configuration will essentially just block objectionable SSH traffic. If you decide to extend it, create a /etc/fail2ban/jail.local file to supplement the default /etc/fail2ban/jail.conf file (the former augments the latter).

As others have mentioned, there are a number of resources available. Do not make all suggestions blindly: some are of questionable efficacy and complexity.

ufw will allow precise tuning of iptables. Watch /var/log/ufw.log for entries indicating traffic being dropped, either appropriately or not. Once more services are added (and secured), introduce related rules into ufw one by one. If your system is exposed to the general Internet, be particularly careful with such services' configurations.

The above minimal ufw commands will prevent many commonly used network services on the local network, such as CIFS. Some packages install custom ufw application definitions which can be listed with the ufw app list command (e.g., Postfix, Apache). Such applications usually open the services to all, as opposed to the just the local network.

proto• 13 years ago

Linux is, unfortunately just as vulnerable to cross-site scripting and other browser-based attacks. The browser is also the biggest vector for Windows, and Linux has no better immunity, unfortunately.

I would recommend using NoScript or eqiv. plugin for your browser.

In my opinion, Windows' biggest security flaw, is teaching users to install software via the browser. But for non-open-source software ecosystems, it's quite difficult to create a white-list of safe programs.

My second recommendation is to, as much as possible, only use software from your repository.

In regards to the other recommendations about firewalls, while definitely not bad advice, if you are behind a NAT router, and on a small, trusted LAN, I wouldn't worry too much about it personally.

Ask HN: I finally ditched Windows for Ubuntu - How do I keep things secure?

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