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

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28
votes
2answers
1k views

Should security updates always be installed?

We are a small shop, with no real sysadmin. So developers (Java EE) also try to maintain Ubuntu server 12.04. When I login a terminal and I see messages like: 6 packages can be updated. 6 updates ...
12
votes
2answers
10k 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
2answers
7k 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 ...
6
votes
2answers
1k views

How to secure grub recovery mode

When I boot system in to recovery mode from GRUB menu, I can get in to all powerful root without entering any password, thus insecure. How I can secure this and ensure that a password is asked every ...
5
votes
1answer
241 views

What security policies exist in place for packages and scripts?

I did have used Microsoft Windows since Windows 98 to Windows 7. I have found lots of security vulnerabilities by myself about how viruses, worms, spyware etc. compromises the system. Microsoft ...
0
votes
2answers
1k views

Best Practice for Installing Java on Ubuntu / is it secure?

Much has been said about the security risks associated with Java. However the burp suite (pen test) depends on Java. Is it secure to install Java? if so, how to properly do it? My Ubuntu is a web ...
7
votes
2answers
1k views

What is a security update?

Why are some updates called Important security updates? How are they different from other updates? Is my system insecure, If I don't install them? How can there be very frequent security updates? ...
4
votes
1answer
2k views

Where do I get the AppArmor 2.4 compatibility patch?

I just compiled the 2.6.39-rc1 kernel and AppArmor complains about a missing /sys interface (plus, it slows down the boot). Where do I get the AppArmor 2.4 compatibility patch AppArmor asks for?
-10
votes
2answers
720 views

I think my PC is being hacked. What should I do? [closed]

I'm afraid I'm being hacked: My Ubuntu is receiving inbound traffic while my PC is disconnected from Ethernet and WIFI, so my question is, how am I receiving inbound traffic? I even have a firewall ...
20
votes
7answers
1k views

How should a server be secured? [closed]

Talking towards Ubuntu 10.04, server edition, what tools/practices would you recommend to secure the server?
28
votes
2answers
789 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 ...
17
votes
2answers
9k 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 ...
14
votes
5answers
23k 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 ...
15
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 ...
51
votes
3answers
27k views

Difference between PGP and GPG

What are the main differences between PGP (Pretty Good Privacy) and GPG (GNU Privacy Guard) in relationship with security in Ubuntu and Launchpad?
15
votes
6answers
15k 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, ...
15
votes
3answers
8k 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
2k 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 ...
5
votes
2answers
1k views

How to truly secure a hard-drive?

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
354 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 ...
3
votes
1answer
760 views

Security and Ubuntu [closed]

I have used Linux before (Ubuntu 13.04), but I have moved back to Windows after having compatibility issues with Windows programs ex. AutoCAD and ProEngineer Wildfire. However, I tried using Linux ...
8
votes
1answer
1k 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
1answer
599 views

What is the 'libc gethostbyname buffer overflow' and how can I protect myself from it

Apparently there is a bug in the GNU C Library, that can cause a buffer overflow? What exactly is it, and how can i protect myself from it?! Reference: oss-security - Qualys Security Advisory ...
3
votes
2answers
8k 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 ?
53
votes
1answer
6k 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 ...
28
votes
8answers
10k 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 ...
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 ...
23
votes
2answers
32k 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 ...
30
votes
5answers
5k views

What's wrong with using sudo?

In a comment here I've been told that unnecessarily using sudo should be avoided. While it wasn't needed in that particular case, I don't see any harm in using it. I think that when executing trivial ...
5
votes
1answer
9k views

Fingerprint reader driver for Validity Sensors Fingerprint scanner

prakhar@pr3d4tOr:~$ lsusb -s 001:003 -v Bus 001 Device 003: ID 138a:0018 Validity Sensors, Inc. Fingerprint scanner Couldn't open device, some information will be missing Device Descriptor: bLength ...
31
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, ...
16
votes
2answers
15k 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, ...
14
votes
2answers
1k 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?
12
votes
4answers
17k views

How can I block ping requests with IPTables?

and stealth specific ports?
6
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 ...
5
votes
2answers
831 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 ...
3
votes
3answers
2k views

Packet Sniffer found, what next?

After a download yesterday my computer crashed. I updated today and checked for rootkits. I found a packet sniffer eth0: PACKET SNIFFER(/sbin/dhclient[3966]) How can I remove this?
13
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 ...
9
votes
3answers
4k 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 ...
20
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 ...
14
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
4answers
1k 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. ...
6
votes
1answer
5k 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 ...
3
votes
3answers
3k 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
6k 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 ...
12
votes
1answer
952 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: ...