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

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Harden Ubuntu Server 14.04

I have a personal server I primarily use for downloading media. Besides hardening ssh, I was wondering if there are any other preferred means to securing the rest of the server, virus', so forth and ...
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0answers
10 views

Ubuntu 14.04.4 LTS: Firewall - block countries

I'm having trouble with my VPS. IPs from both China and Russia is trying to brute-force my VPS (not like there's anything interesting), and it's annoying. I'd like to ask, if there's any way I can ...
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0answers
13 views

How to blacklist certain commands from aliasing?

There are certain important commands I use a lot such as sudo, cd and ls which if malicious aliases were created of could cause some major problems, especially with the first listed. And I know that ...
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1answer
31 views

Could I have gotten a virus from this?

So I was browsing a thread in 4chan that had dirty pictures. Yeah haha pervy whatever. There was a link to a page that the user said I could use to download a dirty video. I didn't think it was ...
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0answers
46 views

Is my Ubuntu Desktop under attack?

I am currently facing random freeze of my Ubuntu(16.04) desktop and screen fills up with the garbage pixels. I even cannot start command line using Ctrl-Shift-F1. Every time I have to manually do the ...
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1answer
40 views

Unable to clear recent files from history

I run a 64 bit version of Ubuntu 15.04. Often when I delete recent history using the Security and Privacy application, I can still see the files in the Unity lens when I press the Windows key (both ...
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1answer
17 views

How to audit file created under a specific path?

I would like to know if there is an audit tool I can use to monitor the file created under a specified folder? I would like to know the user and program used (ftp, ssh , php) to create the file.
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0answers
11 views

Vulnerability ( CVE-2014-4608) recurs in Linux 3.17.2-4.5? [closed]

Recently, I have done some tests with Linux-kernel bug commits. And I found that the patch codes ( fixing CVE-2014-4608, click here to the code) didn't appear in the version 3.17.2 to 4.5. I'm just ...
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0answers
10 views

Can I configure unattended-upgrades to reboot only for urgent issues?

This is how to configure unattended-upgrades to reboot the machine if needed: Unattended-Upgrade::Automatic-Reboot "true"; (in /etc/apt/apt.conf.d/50unattended-upgrades ) But is there no way to ...
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0answers
27 views

PHP5: upload_max_filesize/post_max_size security concerns [closed]

The default values of those settings are very low: < 10M (my guess is: they stem from ancient times and are not up-to-date). Hence I massively increased them to make them fit my needs. But the ...
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1answer
23 views

Mosquitto Configuration on 16.04

I installed the MQTT mosquitto package from the standard repos on a fresh 16.04. I'm confused about where to place/edit the conf file for MQTT to work with a username and password. There is a conf ...
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1answer
22 views

virus threat detected in /usr/lib/shim

I recently ran a virus scan with clamtk and was pleased that not much came up except for one system folder: /usr/lib/shim with the following files being flagged: fallback.efi.signed ...
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1answer
66 views

Torrents blocked by ISP in Ubuntu but on Windows works fine

I have a dual boot system: Ubuntu and Windows. When I use Transmission for torrents, it doesn't download anything and in the browser torrents sites are blocked, But if I do same thing on Windows in ...
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2answers
31 views

Replace Windows 7 Entirely W/ Ubuntu & Security Feature Allows Wildows Files? [duplicate]

If Ubuntu supports files from windows, doesn't this defeat the "security" of Ubuntu? Obviously not a technie How to install and "replace" Windows 7 entirely, and get Microsoft out of my desktop. ...
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0answers
15 views

x11vnc configuration with SSH

I have followed after those steps of setting up the x11vnc, Run the following to install: sudo apt-get install x11vnc sudo x11vnc -storepasswd **yourVNCpasswordHERE** /etc/x11vnc.pass sudo nano ...
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0answers
61 views

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
32 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
62 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 ...
4
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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 ...
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1answer
30 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 ...
3
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2answers
47 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
7 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
39 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 ...
25
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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 ...
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4answers
94 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
78 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 ...
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1answer
31 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 ...
2
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1answer
79 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 ...
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3answers
282 views

Should the root / have 777 permission?

Most of the contents is 755 though. Is this a problem?
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0answers
21 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 ...
-5
votes
1answer
187 views

Ubuntu LTS 16.04 – Security – Code-Review [closed]

Just installed the new Longterm Version. Since I'm new in the Ubuntu world, I was a bit shocked what is going on "in the year 3 after Snowden". So here are my questions: How can I delete (realy ...
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1answer
31 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
88 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
40 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
26 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
27 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
26 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
28 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 ...
0
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3answers
386 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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0answers
24 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 ...
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2answers
21 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
11 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 ...
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0answers
16 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
496 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 ...
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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?
9
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2answers
2k 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
22 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, ...
7
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2answers
74 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
70 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 ...