Security covers a wide-ranging set of topics including Users, Permissions, Authentication, Authorisation, Upgrades, Firewalling, Hardening, etc.

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28
votes
2answers
766 views

What precautions should I take with .debs I find on the internet?

So I was browsing the web the other day, and I came across a few places that wanted me to download .deb files - and since those are installed by root (and as such have the "powers" and capabilities of ...
26
votes
8answers
3k views

What do I have to do before giving away my Ubuntu machine?

I have an old laptop that is running Ubuntu. Now I want to give away this laptop, but I want to remove all private data. So what should I remove? I don't want to format the whole system, because the ...
13
votes
2answers
1k views

Is it a bad idea to run SELinux and AppArmor at the same time?

My corporate policy says that Linux boxes must be secured with SELinux (so that a security auditor can check the 'yes, we're extremely secure!' checkbox for each server). I had hoped to take ...
12
votes
6answers
10k views

How can I audit users and access attempts to SSH on my server?

I've had a few security problems with a server of mine, a few SSH users have been setting up fires aka giving problems. I would like to: Track user logins and logouts Track activity of these SSH, ...
13
votes
3answers
6k views

Untrusted application launcher?

Some time ago, Ubuntu introduced a Security "feature", that would only allow trusted .desktop apps to be run, on other apps it would pop up a message. Nothing new so far, However, said Message used ...
9
votes
2answers
1k views

What is the least insecure way to store a password that is used by a script?

I have a Bash script that automatically authenticates with a service using my username and password. The credentials are currently stored as plain text within the script. What precautions should I ...
9
votes
2answers
5k views

What does “pts/” in the output of w mean?

When I run w - to see who is logged on and what they are doing, i see this: USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT user tty7 :0 08:14 10:32m ...
3
votes
2answers
2k views

How to make a partition truly secure?

When I boot from an USB stick into my laptop I am able to mount and connect through chroot to the my hard drive and browse my files without a problem, while this has been something very very useful in ...
8
votes
2answers
330 views

How do I get security updates for restricted/partner packages?

I want to perform just security updates on Ubuntu 12.04 LTS, keeping the rest of the system unchanged. I need to do this from the command line, no the GUI update manager. I have implemented the ...
8
votes
1answer
2k views

Why should I use gksudo for Gtk apps instead of sudo? [duplicate]

I read somewhere that people should use gksudo for applications that use the Gtk GUI instead of sudo? What's the reasoning for this?
3
votes
2answers
7k views

How do I check if someone accessed my computer?

I need to check the list of files accessed in my computer (ex: yesterday on particular time). Is it possible? Or I need to check whether anybody accessed my computer (when I left it unlocked) or ...
6
votes
1answer
3k views

Does Ubuntu One effected by NSA according what Edward Snowden published? [closed]

It is very important for me to keep my files in a safe Host. I use ubuntu one because of ease of using in Ubuntu. You think is it safe enough of spying ?
2
votes
2answers
347 views

No user name/password required when exploring from live USB?

A few months back when I buggered up my netbook and then booted into it to get information from it using a live USB. (Thinking that was 10.10) When I was copy/pasting this to another USB at no time ...
50
votes
1answer
5k views

How to protect Ubuntu from fork bomb

I heard someone talking about a fork bomb, I did some research and found some dreadful information about some strange looking characters people can have you type at the command line and as a result do ...
27
votes
8answers
9k views

How to set up a headless server?

I have a ubuntu development server at work. It is an old rack server that is located somewhere in the company's dungeon, where nobody ever goes. The only way it can work is as a so-called headless ...
14
votes
2answers
7k views

What is the 'ptrace_scope' workaround for Wine programs and are there any risks?

To run certain Windows programs in WINE you need to this workaround: echo 0|sudo tee /proc/sys/kernel/yama/ptrace_scope According to the support websites, this is due to a bug in the Ubuntu kernel ...
20
votes
3answers
1k views

What automated intrusion notification/detection setup is good for home desktop use?

I've been using Linux for quite a while now and I always feel the need to have a passive software / script setup which can alert me of any suspicious network activities like scans, failed login ...
16
votes
4answers
5k views

Package denyhosts in Ubuntu Trusty Tahr is deleted: temporary or forever?

While doing a test-upgrade of our Ubuntu server to 14.04, I found that the package DenyHosts is no longer available. Installing it gives following error: apt-get install denyhosts Reading package ...
15
votes
2answers
19k views

How can I allow SSH password authentication from only certain IP addresses?

I'd like to allow SSH password authentication from only a certain subnet. I see the option to disallow it globally in /etc/ssh/sshd_config: # Change to no to disable tunnelled clear text passwords ...
13
votes
2answers
871 views

How can I tell that apparmor is working?

Some questions I want answered in the answer: How do I know if apparmor is running? How can I tell if it's working well?
10
votes
2answers
10k views

Patch OpenSSL CVE-2014-0160 on ubuntu 12.04?

NO, this is not a duplicate of How to patch the Heartbleed bug (CVE-2014-0160) in OpenSSL?. So, read on. I am seeing conflicting information with respect to Ubuntu 12.04: The Heartbleed page claims ...
5
votes
2answers
1k views

Is Chromium in Ubuntu's repository safe to use since it's so out of date?

Is Ubuntu Chromium still safe to use since its so out of date?
5
votes
2answers
775 views

Precautions during SSH [duplicate]

Possible Duplicate: How can I audit users and access attempts to SSH on my server? I recently had to give away my Ubuntu 12.10 root password to one of my friends so that he could SSH into ...
12
votes
3answers
1k views

How do I call a dialog for authentication?

I am writing a gui program using wx module in python. In program whenever I am accessing a folder which requires root privilege then it asks password at terminal but I want to display the dialog to ...
10
votes
2answers
6k views

How do you set requirements (such as minimum length) on passwords?

Is there any way to set up minimum passcode requirements, such as a minimum length, requirement of mixed case alphanumerics and at least 1 symbol in the passcode, and enforce that at passcode changes? ...
9
votes
3answers
3k views

How do I safely use a virus infected USB drive in Ubuntu?

I have an USB drive which I know is virus infected (an anti-virus on my friend's machine detected it). Unfortunately neither of us know the virus name and I don't want to take the risk of plugging it ...
13
votes
4answers
2k views

What is default password?

What is the difference between default and login? And what does Default Keyring mean? When I run some applications(Emphaty etc), Unlock Keyring window launched first, then it requires me password. ...
13
votes
3answers
2k views

Ubuntu vulnerable to malware sites?

I just browsed a site a while ago that was flagged as an "attack site" or has malware, but Firefox didn't warn before I went into it. Only when I opened a new tab with another page from the site did ...
6
votes
1answer
4k views

How to either configure, or completely remove policykit? [closed]

Where can someone get policykit related tools? gnome-policykit-authorizations polkit-config-file-validate polkit-policy-file-validate And if getting them is not an option: Where can I get a full ...
5
votes
4answers
4k views

Is installing wine in Ubuntu safe? [duplicate]

Possible Duplicate: Risks/Disadvantages associated with Wine According to many articles like this one, it says that windows is more vulnerable to virus. I recently installed wine on my ...
3
votes
3answers
2k views

Disable usb mass storage

I want to disable usb mass storage on Ubuntu desktop 10.04, 11.04 and 11.10. As security policy to avoid data leakage. But in case of emergency there easy way getting usb mass storage back.
2
votes
0answers
7k views

Automatic unlocking of keyring? [duplicate]

Possible Duplicate: How can I stop being prompted to unlock the 'default' keyring on boot? I like the idea of gnome-keyring, but having it ask for the unlock password after every ...
19
votes
3answers
1k views

What is the “Free software only” option when installing Ubuntu?

When installing Ubuntu, you get a Free software only option. Does that Free software only option mean Free as in beer or Free as in freedom? When I say free as in freedom, I mean FSF type of ...
7
votes
4answers
14k views

What rules to use for UFW?

I've decided to enable the UFW that comes with Ubuntu just to make my system even more secure (especially after watching a video of a person whose computer actually got infected!), and I've enabled ...
3
votes
1answer
222 views

Is there a security risk if a password can be reset easily?

was just reading up on changing password complexity and I stumbled upon this: https://help.ubuntu.com/11.04/ubuntu-help/user-forgottenpassword.html Isn't that a big security risk? Assuming someone ...
2
votes
6answers
5k views

How do I encrypt/decrypt file within gedit?

In the previous version of Ubuntu (eg: maverick, natty), I used to do a: sudo apt-get install gedit-plugins seahorse to have the ability to encrypt/decrypt file within Gedit after enabling the ...
1
vote
2answers
567 views

verifiying ubuntu iso with repository gpg-keys

I want to verify that a downloaded iso is not being poisend by the NSA or any other immoral agent. To do this I would very much use a signing-checking way. I am aware of VerifyIsoHowto. Still I am ...
0
votes
1answer
556 views

Can I prevent/restrict standard users from installing/uninstalling software?

Can i prevent/restrict standard user from installing/uninstalling software in Ubuntu 12.04 desktop?
19
votes
3answers
9k views

How to block internet access for wine applications?

Is it possible to prevent specific wine applications or any wine application from accessing the internet? When using certain apps under Windows, they were trying to access the internet from time to ...
49
votes
8answers
3k views

What are the risks of NOT using a firewall (home computer)?

Since a password is required to be a superuser (to install and modify programs), what are the risks to not use a firewall under Ubuntu ? More particularly if I am using a NAT router ?
28
votes
7answers
1k views

What precautions should I take when exposing my desktop directly to the internet?

I've always used my Ubuntu desktop behind the security of a router with NAT, but there have been a few times when I've had to plug it directly into an active cable modem. In general, what precautions ...
12
votes
5answers
19k views

How to secure ubuntu server from bruteforce ssh attacks?

I have my passwords secure, but I heard people complaining about perfomance of a server going down drastically when a bruteforce attack is taking place. How can I secure my ubuntu 10.10 server from ...
27
votes
5answers
10k views

How to sandbox applications?

I want to run small untrusted programs, but restrict them from accessing any files outside of their folder, network access, and everything else that they don't really need. What is the simplest way to ...
26
votes
1answer
1k views

How to know if a authenticate box is real or fake?

For example, someone creates a fake Authenticate dialog to get my root password. How to know if it is real or fake?
17
votes
4answers
16k views

Which free VPN providers support Ubuntu?

Can't find any free VPN provider for Ubuntu. I tried looking into old questions but they seem to be outdated.
9
votes
3answers
12k views

Security camera system server

I'd like to setup a Security Camera system which is captures and stores video streams into Ubuntu Server From 2 wireless Cameras. Which type of motion-detecting wireless camera you suggested? Are ...
18
votes
3answers
5k views

Is this command to remove old kernels safe to use?

While browsing the internet for Ubuntu articles, I came across this command: sudo dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ...
17
votes
2answers
5k views

What is the apt equivalent to “rpm -V” (Verify installed packages)

On a RedHat/CentOS system, I can verify the installed RPMs on my system using rpm -V. What is the Ubuntu or apt equivalent of this command?
30
votes
4answers
1k views

Does Ubuntu generally post timely security updates?

Concrete issue: The Oneiric nginx package is at version 1.0.5-1, released in July 2011 according to the changelog. The recent memory-disclosure vulnerability (advisory page, CVE-2012-1180, ...
12
votes
3answers
28k views

How to disable IPv6 permanently?

How can we disable IPv6 system wide via terminal commands? I've read editing /etc/modprobe.d/aliases and replacing: alias net-pf-10 ipv6 with: alias net-pf-10 off alias ipv6 off Is this safe ...