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

learn more… | top users | synonyms

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 ...
19
votes
2answers
4k views

How safe is Ubuntu?

Last week I started desktop sharing using krfb. Continuing from my last session, it appears that the process restarts itself. Two days ago I noticed messages popping up saying something like ...
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 ...
19
votes
2answers
1k views

Why should I trust the “System program problem detected” dialog?

This always shows up a few minutes after I log in: I have no idea what it is. If I click Report problem, it asks for my password: This is exactly what I would do if I wanted to steal someone's ...
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?
17
votes
1answer
3k views

Update Manager does not ask for password anymore [duplicate]

I have realized this behaviour recently. Before that each time the update manager poped up to tell me there are updates and I tell it to install them it will ask me for a password. But since recently ...
17
votes
2answers
664 views

Accidentally typed password in username input, any logs to clear?

I have accidentally typed my password in SSH's interactive username prompt. Are there any log files that I should clear?
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 I tried looking into old questions but they seem to be outdated.
16
votes
5answers
5k views

Is there a preinstalled or automatic firewall?

Does Ubuntu come with a preinstalled or automatic firewall? If not, do I need one? I've read some articles about the advantages of linux over other operating systems about security (no need to have ...
16
votes
3answers
2k views

What's the difference if I use Windows 7 as a Standard User vs if I use ubuntu?

Ubuntu is secure for various reasons, one of them, a major one I believe, is that when you try to install a software/app via terminal/store an authentication box pops up asking you for your password. ...
16
votes
1answer
51k views

How do I scan for viruses with ClamAV?

I installed ClamAV via Terminal (Ctrl+Alt+T) with: sudo apt-get install clamav but how can I scan for viruses?
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 ...
16
votes
5answers
11k views

How to detect and remove a Linux trojan?

I recently (re)stumbled upon this: Linux Trojan Goes Unnoticed For Almost A Year (Unreal IRCd) Yes, I know that adding some random PPA/software from an untrusted source is asking for trouble (or ...
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 ...
15
votes
7answers
8k views

Access Prompt keeps asking for GMail password

A pop up keeping appearing in Ubuntu (running 12.10), asking for the password to my gmail account. The icon has a silver shield, and it is labeled Access Prompt. The actual window has an image of ...
15
votes
3answers
2k views

Risks/Disadvantages associated with Wine

Can wine as a whole or the windows applications installed via wine pose some kind of risk to an Ubuntu installation? This question arose in my mind when I read this answer to my earlier question ...
14
votes
6answers
4k views

Does spyware exist for ubuntu?

Someone I know said he had put spyware on my computer. Is he talking crap? I've been using Ubuntu 12.04 for nearly 3 years now and I've never seen any type of spyware, remote keyloggers or RATS ...
14
votes
6answers
11k views

Ubuntu One behind a proxy, how to make it work?

I am behind a web proxy server at work (no authentication) and I have set it up in Gnome (configuration applied system-wide). It works fine for accessing internet with a browser, but numerous ...
14
votes
4answers
18k views

GUI for iptables?

I would like to secure my server and it seems that IPtables is one of the first steps. Unfortunately editing the rules in a terminal is a bit complicated and dangerous (those who ever did an iptables ...
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 ...
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 ...
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 ...
13
votes
2answers
366 views

Does linux have a signature system for executables?

Windows has a signature system which allows you to make sure that an executable hasn't been modified after it has been signed. I used to use this as a security measure in Windows. Does linux have ...
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 ...
13
votes
1answer
697 views

In which country(s) is our Ubuntu One data stored?

In view of the UK government's new internet snooping proposals can anyone answer this question about the physical location of our data?
13
votes
2answers
255 views

Should I include logs that contain “sensitive information”?

Sometimes, when info is being collected by ubuntu-bug (either automatically following a program crash or by manually calling it) the following dialog pops up: Should I include these files or not? ...
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?
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
4answers
6k views

Web Server Best Practices: Directory Structure & Security

I would like to utilize Ubuntu server as web server, but I want to make sure I follow best practices for setting things up. I want to ensure I set the directory up in the best location and understand ...
12
votes
2answers
3k views

Disable password access through SSH?

I'm setting up a server for backing up my desktop box remotely. I want to prevent remote password access to the server, permitting only users with private keys (AKA my desktop box) to access it. How ...
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 ...
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 ...
12
votes
8answers
3k views

Is a Firewall really necessary these days? [closed]

should I install something like gufw?
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, ...
12
votes
2answers
9k views

chkrootkit says /sbin/init is infected, what does that mean?

I recently ran chkrootkit and got the following line: Searching for Suckit rootkit... Warning: /sbin/init INFECTED What does this mean exactly? I heard this was a false positive, ...
12
votes
1answer
658 views

Why is the automatic login disabled for users with encrypted home?

I've tried to setup an autologin, but that isn't possible, because my home is encrypted. What are the reasons for this? PS. Here I have described my problem: ...
12
votes
1answer
522 views

How to deal with malware on my laptop?

I am fairly certain that my Ubuntu 13.10 laptop is infected with some sort of malware. Every once in a while, I find a process /lib/sshd (owned by root) running and consuming lots of cpu. It is not ...
12
votes
4answers
442 views

Where are release notes from security updates that were installed in the background?

My Update Manager is set up to download and release security updates silently in the background. Therefore release notes are no longer displayed. I wonder if there is a way to read the release notes ...
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 ...
12
votes
2answers
510 views

How do I require Two Factor Authentication to log in?

Running 12.04. I am trying to separate my wrapped-passphrase for my encrypted home folder to require a USB drive be present to login. I followed the instructions here and added the drive to my ...
11
votes
4answers
21k views

What antivirus programs are available?

What antivirus programs are available for Ubuntu? We previously used Symantec Endpoint Protection but it does not work in Ubuntu.
11
votes
3answers
41k views

What are the Major Differences between Ubuntu 12.04 and 12.10 in terms of Security? [closed]

I use Ubuntu 12.04. Recently, 12.10 was released. I'd like to upgrade but I want know what the benefits are in using Ubuntu 12.10 over Ubuntu 12.04 first. My requirement is here Security , is there ...
11
votes
1answer
728 views

Why doesn't Chromium get quicker updates?

I'm running 10.04 and i'm still only on v12 even though we've just had v14 pushed out by Google and on 3 Sept a big update to v13 that revoked the Diginotar certificates. I was running a ppa at one ...
11
votes
1answer
288 views

Strange POST requests to my Ubuntu server - am I in trouble?

I have an Ubuntu Server 12.04 installed on a VM. This server has apache2-mpm-prefork and libapache2-mod-php5 installed. I was looking through the logs and recently came across these rather ...
11
votes
3answers
3k views

Is AES-NI fully supported?

Has support for the Intel AES-NI hardware crypto acceleration been added to Ubuntu (LUKS, kernel, OpenSSL libs, etc)? If so, starting with which version? Here is a list of Intel processors supporting ...
11
votes
4answers
15k views

How can I block ping requests with IPTables?

and stealth specific ports?
10
votes
9answers
666 views

What's the best way to store a passphrase?

I've recently enabled Ubuntu's encrypted /home/ directory features and I was asked to remember a passphrase in case I would need to recover the data manually. What is the best way to store this ...
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 ...
10
votes
3answers
793 views

How can I make everything just assume I'm running as the superuser?

Is there a way I can make things just assume that when I run them I am running them as a privileged administrator (AKA root)? I know it could be dangerous and all, but its a risk I'm willing to take ...