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

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Skip sign verification at module loading

With secure boot enabled, is there a way to load a custom kernel module not signed, or signed with an auto-generated private key? Trying to load my custom module, insmod exits with the error Required ...
4
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1answer
40 views

Using binfmt-misc in conjunction with xattrs

I currently use a piece of sandboxing software on my 14.04 machine that isolates Linux binaries from one another (Using a special type of namespace isolation different than AppArmor) Currently, the ...
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1answer
196 views

Apparmor Init Failed, Exit Code 123

Apparmor fails boot and command line start with same result as below x@x-NICEPUTER:~$ systemctl --failed UNIT LOAD ACTIVE SUB DESCRIPTION ● apparmor.service loaded failed failed ...
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1answer
2k views

Why hasn't Trusty received the updates for OpenSSL's CVE-2016-2108 and CVE-2016-2107? [duplicate]

OpenSSL released a security advisory, warning users of two recently discovered vulnerabilities: Memory corruption in the ASN.1 encoder (CVE-2016-2108) Padding oracle in AES-NI CBC MAC check (CVE-...
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1answer
44 views

Start firefox using apparmor (for extra security)

I'm having some trouble starting firefox with apparmor. Here's what I've run: $ sudo aa-enforce /etc/apparmor.d/usr.bin.firefox $ firefox /usr/lib/firefox/firefox: error while loading shared ...
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2answers
55 views

How to check for executable files in a given directory and its sub-directories?

I understand that it is a bad practice to keep files owned by oneself in one's home area which are executable, so I am in need of a script/tool which checks recursively through a given directory (in ...
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0answers
11 views

gnome-session-Unity logs - VNC connection messages

I recently realized that my 'Desktop Sharing' was turned on and as a result there were numerous Brute Force attacks on my system. Going through the gnome-session-Unity logs I have searched to see if ...
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2answers
48 views

Is there anything that should be done to increase security on a new system? [closed]

Let's assume I just installed Ubuntu on a laptop. This laptop may be used in different networks with different security measurements (at home, university, work place). Is there anything that should ...
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6answers
4k views

Personal computer hacked: How do I block this user from logging in again? How do I find out how they are logging in?

I am 99.9% sure that my system on my personal computer has been infiltrated. Allow me to first give my reasoning so the situation will be clear: Rough timeline of suspicious activity and subsequent ...
4
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4answers
178 views

How does FDE (Full Disk Encryption) work so quickly?

I'm curious about how does Ubuntu's full disk encryption works under the hood. Here's an example: Considering the following string as all the disk's content: hello world After applying some kind ...
9
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1answer
87 views

How to ensure user separation on an old school shell server

I want to run an old school shell server for a couple of people, ie. one where users get ssh access so they can run software (their own or provided). My concern is appropriate separation between users....
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1answer
58 views

How can I encrypt my pendrive with password? [duplicate]

In windows 7 or windows 8, I can use BitLocker Drive Encryption to encrypt and set a password in my pendrive but i am unable to access files of my pendrive in Ubuntu. Is there is any method to ...
3
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1answer
142 views

How to use SSL and SASL with irssi under Xenial Xerus?

I would like to connect to Freenode with irssi using both SSL and SASL. Instructions for using the script cap_sasl.pl that worked for older versions of irssi now show the following error under Xenial ...
3
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3answers
317 views

Should the root / have 777 permission?

Most of the contents is 755 though. Is this a problem?
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0answers
25 views

shutdown or reboot after entering wrong password x times

My laptop is configured with a bios password to unlock the encrypted ssd. Most times I don't shut it down and use just suspend/resume - this of course leaves the ssd accessible. To increase security ...
0
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1answer
32 views

Does posting my computer name publicly make my system vulnerable?

I am wondering if it is paranoia and/or privacy overkill to block out one's computer name when posting terminal output in public forums? I don't know enough about networking to know if it's possible ...
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1answer
106 views

Is Ubuntu 16.04's Snap format secure?

A recent leak claims that Ubuntu's new Snap Format is not secure - http://news.softpedia.com/news/developer-claims-that-canonical-s-new-snap-format-isn-t-secure-on-ubuntu-desktop-503287.shtml. Since ...
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0answers
46 views

How to trigger lock-screen on visiting a website?

The website in question is my Google Drive. I have many confidential data in my Google Drive. And my google account is signed in on my laptop. Also I tend to leave it unattended at times. I want to ...
4
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1answer
39 views

How can i find that which file was copied from my pendrive last time?

I forget my pendrive in my office. I have doubt that someone copies my important documents and files from my pendrive. Is there any method to find that which file is copied from my pen-drive? Please ...
0
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1answer
28 views

How to detect screenshots in Ubuntu?

Apart from monitoring keystrokes for Print Screen, is there a way for a tool or software running in Ubuntu (whatever the desktop) to detect that a screenshot or video recording of the whole or a part ...
0
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1answer
27 views

Secure way of geting checksum

I was just wondering, is there any way of how to securely get checksum from major branches of ubuntu? As a general rule I do not trust anything that can be easily manipulated for that I do not believe ...
2
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1answer
49 views

Is choosing 'Security Updates Only' on installation of Ubuntu Server enough?

I want necessary security updates on my Ubuntu servers, without my interference. In general, do I need to do anything else after selecting the 'Security updates only' option in the automatic updates ...
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3answers
408 views

What does this “find” command do?

I am so beginner on Linux and I have run the following command while I am on /root: find . -type d -exec chmod 770 {} \; && find . -type f -exec chmod 660 {} \ I meant to run that on a ...
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1answer
42 views

Ubuntu Touch - Screen locking fade issue

On my Ubuntu phone, I have set my screen lock to come on after a minute of none use. This is in the Settings > Security & Privacy > Locking & Unlocking. The lock does come on as requested ...
0
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2answers
22 views

Regular security checks on server [closed]

I am administrating a server and obviously i am slightly paranoid if its security is compromised. Hence i regularly try to check if the security is still intact. Here are the things that i do roughly ...
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0answers
12 views

Evaluating URL Whitelists for Security Threats

I have a very long list of URLs to whitelist on my Ubuntu Squid proxy. I have looked through this list that was provided by another group and there are sites in the list that seem to range from "...
0
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0answers
21 views

lxcbr0 stop container communication

I'm creating LXC containers to be used by different users but required each container to connect to lxcbr0 to provide remote access. How can I restrict with LXC that containers on a default bridge ...
2
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1answer
533 views

What do I do about Badlock on Ubuntu 14? [duplicate]

So, the Badlock bug (www.badlock.org) that was revealed yesterday, was not as terrible as feared. And yet, it seems prudent to patch samba ASAP. However, just prior to releasing the bug, the samba ...
13
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2answers
4k views

What is the name of the security concept that explains why Linux asks for root password?

Whenever I'm installing new software or making changes to the system, Linux asks for the root password. What is the name of this security concept and where can I research more information about it?
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2answers
3k views

What is the 'Badlock Bug'?

A user on the Ask Ubuntu General Room posted a link to Badlock. After some googling around, all I can find is that it is a mysterious security bug, that uses the same website template as Heartbleed. ...
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0answers
34 views

Restrict user to run only one program with Wine

I want install Wine and Picasa for an user. I want prevent the user from running *.exe-Files basically for security reasons. In the past (bevor 3-4 years, another Ubuntu-Installation) I discovered, ...
8
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2answers
103 views

Is the lock screen secure?

I have a fully encrypted drive so I know when my laptop is turned off that nobody can access my data but what about when the screen is locked with my root password? It is often impractical to turn ...
0
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1answer
53 views

File/folder protection that even government cannot break [closed]

If I have some intellectual property file that under no circumstances my competition can view, what is the best and most secure way to protect them? I know that there are many encryption apps for ...
3
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1answer
76 views

is the current Adobe Flash 'ransomware vulnerability' affecting Ubuntu users?

Currently there is an important release from Adobe telling users to update their Flash after learning of certain vulnerabilities where users computer are infected with ransomware. One of the many news ...
8
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1answer
368 views

How to prevent users from changing their password to one of the last X passwords?

I have an Ubuntu GNOME 15.10 with GNOME 3.18 system which I would like to set up so that the users using it cannot set a new password as one of the previous X passwords, how can this be achieved? ...
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0answers
26 views

Ubuntu Vulnerabilities Filtered By Severity

It there a page that provides a list of Ubuntu security vulnerabilities by priority? The CVE Tracker seems to be colour coded by priority but I'm looking for something that I can easily filter based ...
0
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1answer
45 views

Permission denied for ubuntu shell user to list home directories of users

When I use shell I can't list the directories of local home users created by useradd or through virtual min ls -ls /home/someuser/ permission denied but I can list directories created by root. ...
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1answer
60 views

Fix duplicate error sudo apt-get update .Help me!

I trying update security ... sudo apt-get update And faiel... Reading package lists ... Done W: Duplicate sources.list http://archive.canonical.com/ubuntu/ precise entry / i386 partner Packages (...
5
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2answers
162 views

Can someone determine my previous sudo password was if they have access to my machine and my new one?

I have found a bug and the developers to whom I reported this bug to want me to send them the VM with the bug. They want me to send them the password and the VM in its current state (a snapshot). I ...
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0answers
51 views

Is it possible to make HASP4 key working in 14.04 x64?

I'm trying to install HASP4 service on Ubuntu 14.04 and for now I don't know why key is not accessible over network. What I have: root@zentyal:/etc/init.d# /etc/init.d/haspd restart Stopping hasplmd....
3
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2answers
499 views

Postfix Mail Server. Someone is sending Mails from my server

I am receiving Mails from my own mail server, from a user that belongs to my domain, but is not listed in my mail user db. Here are the logs: 4679 Mar 28 15:54:13 Bumblebee postfix/smtpd[29350]: ...
1
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1answer
27 views

How to check logs for all connections Linux made to servers and/or downloads

I downloaded Sophos a few days eariler, but now I'm worried I might've got it from a bad source. Is there a way to check to see where I've got it from without using the download list of Chromium (It ...
0
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1answer
23 views

Switching back to an older version having high period of security and maintenance [duplicate]

I am presently using ubuntu 15.10. Just want to know if I can switch back to an older version which has more security and maintenance as 15.10 has only a 9 month one.
3
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1answer
83 views

Do malicious web sites ever exploit vulnerabilities in Linux clients? [closed]

Do malicious web sites ever exploit vulnerabilities in Linux clients? Are there any documented instances of this happening in the wild? I am talking about actually taking over the client's machine ...
21
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3answers
1k views

How do I run a sudo command needing password input in the background?

I have recently disabled sudo's authentication caching ability so that it now prompts me for a password every time. And though this is good for security, it has caused one slight problem which I ...
0
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0answers
20 views

want to change password on ubuntu entirely in a single line with no prompt

echo somepassword | passwd --stdin someaccount does not work. Why not? I don't care that it appears in the process table for an instant or is recorded by process accounting.
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0answers
89 views

Can an Ubuntu system get infected by a Macro Virus for MS Office / LibreOffice / OpenOffice?

We are running Ubuntu on several office machines, which are used to handle administrative tasks on a daily basis, e.g. to receive applications via e-mail. We now had the situation that we received "...
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0answers
110 views

How to Set-Up WOL with Intel 82574L?

I am setting up a Ubuntu PC which I only need to do Matlab computation efficiently through VPN connection. My network card should be ok (Intel 9301CT where processor Intel 82574L) which Ubuntu ...
0
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2answers
254 views

linux-image-generic vs linux-image-x.x.x-xx-generic security updates

I have an Ubuntu 12.04 32 bit server running with unattended-upgrades set up to only install security upgrades. I have the linux-image-generic and linux-headers-generic packages installed and am ...
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1answer
62 views

Preventing from DDOS attack

I think I am under a DDOS attack, I found these lines on my access.log: 41.214.156.122 - - [21/Mar/2016:06:01:40 +0300] "POST / HTTP/1.1" 200 41765 "-" "Dalvik/2.1.0 (Linux; U; Android 5.1.1; SM-...