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

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Which Ubuntu releases have fixes for CVE-2015-7547 (“Extremely Severe Bug” with libc getaddrinfo())? [duplicate]

Ars Technica posted an article describing the getaddrinfo() bug and how it is widespread in the Linux world. The vulnerability was introduced in 2008 in GNU C Library, a collection of open ...
4
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5answers
5k views

How can I lock down ubuntu?

I am working on a small project. I have about 20 computers with Ubuntu 10.04 on them, which will be used in a computer lab for elementary, middle, high school and college kids. Some seniors and new ...
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2answers
1k 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 ...
19
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2answers
2k 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 ...
4
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3answers
1k views

How can I tell if a CVE has been fixed in Ubuntu's repositories?

Today a couple of buffer overflows in NTP were announced 1, 2. It looks like updating my system to fix these issues is in order. How can I find out if they have been fixed in the Ubuntu ...
4
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1answer
2k views

Wireless with WEP extremely slow on an Acer Timeline 4810T with a Centrino Wireless-N 1000

I've upgraded an Acer Timeline 4810T to Ubuntu 11.10. Everything works fine except for the darn wireless interface (network manager). I just tested the wireless interface over a non-encrypted signal ...
56
votes
1answer
9k views

Can I make the webcam take a picture when an incorrect password is entered?

I am using a laptop . I was thinking to have a support in my Ubuntu machine. When an incorrect password is entered, a picture is taken later revealing who has been trying to gain access. I have ...
21
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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?
9
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2answers
20k views

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 ...
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 ...
28
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2answers
2k 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 ...
13
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2answers
20k 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? ...
8
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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?
10
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2answers
2k 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? ...
5
votes
1answer
270 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
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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 ...
5
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3answers
6k views

ClamAV: PUA.Win.Exploit.CVE_2012_0110 FOUND (/usr/share/mime/mime.cache)

I recently scanned my system with (I am running the latest version of ClamAV and my definitions are up-to-date): sudo clamscan -r --detect-pua --infected --bell / And this one was of the results: ...
4
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1answer
3k 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?
2
votes
2answers
1k views

verifiying ubuntu iso with repository gpg-keys

I want to verify that a downloaded ISO is not being poisoned 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 ...
61
votes
6answers
8k views

How to secure my laptop so that hacking by physical access is not possible?

I messed up my system earlier, I was greeted with a black screen, when booting in to Ubuntu. When I started up my laptop, I selected the recovery option from the grub menu, and chose fallback at root ...
68
votes
3answers
45k 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?
29
votes
2answers
803 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 ...
29
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8answers
6k 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 ...
50
votes
2answers
57k 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 ...
16
votes
6answers
29k 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 ...
18
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2answers
2k 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 ...
31
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2answers
4k views

Why is everybody so concerned about etc/passwd?

Here is the content of my vagrant machine of this particular file: root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin bin:x:2:2:bin:/bin:/usr/sbin/nologin ...
17
votes
6answers
26k 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, ...
20
votes
2answers
24k 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, ...
20
votes
2answers
15k 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 ...
11
votes
2answers
4k 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
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2answers
2k 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
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2answers
381 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 ...
4
votes
2answers
11k 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 ...
3
votes
1answer
929 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 ...
3
votes
1answer
755 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, how can I protect myself from it?! Reference: oss-security - Qualys Security Advisory CVE-2015-0235 - GHOST: glibc ...
7
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4answers
5k views

Why is X11 a security risk in servers?

I remember reading that servers do not have a GUI because X11 is a security risk. Why?
6
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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 ?
3
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1answer
2k views

Sudo is also user login password - why? how to change?

When installing Ubuntu I can create a user with an encrypted folder, what I always do. Now after the installation the login password for this user is also the sudo password. Is that how it should be? ...
60
votes
2answers
9k 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 ...
31
votes
8answers
12k 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 ...
24
votes
3answers
2k 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 ...
50
votes
7answers
4k 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 ?
33
votes
6answers
6k 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 ...
21
votes
4answers
66k 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 ...
19
votes
3answers
7k 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/^[^ ]* [^ ]* \([^ ...
15
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2answers
3k 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
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5answers
79k views

Get root access for copying files to /usr/share/…?

To be short, I want to copy a folder to a location /usr/share/screenlets/.... in Ubuntu 10.04 system. I tried by logging in as root from terminal giving su. I even changed my user account type to ...
32
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
4answers
24k views

How can I block ping requests with IPTables?

and stealth specific ports?