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

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0answers
23 views

Security of JBOD vs RAID while there is no backup

I have some large amount of data (~40 TB) consisting of small files. The data is currently stored on JBOD. Because the data is not super important and I cannot afford the needed disks there is no ...
2
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1answer
23 views

i3wm screen locking security issue

I am using i3-wm on Ubuntu 16.04. I am locking the screen using dm-tool lock, and it looks good, but I noticed you can circumvent the lock screen by switching a TTY (Ctrl+Alt+F1) and then switching ...
0
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1answer
2k views

Help connecting to my schools wireless network

My school´s hates everybody that dosen´t run Windows 7/8. Therefor, they will not give me support in connecting to my School´s wifi, which i need badly. I have a guide for Windows 7 and I hope that ...
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0answers
21 views

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 ...
0
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0answers
12 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? [duplicate]

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 ...
7
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2answers
75 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 ...
5
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5answers
1k views

How to ensure Wine does not auto run .exe files?

I want to install Wine only for running a program, but I don't want to open any other Windows file (for security). Is it possible to ensure Wine does not execute .exe files automatically? Thank you.
4
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3answers
520 views

Is the lock screen secure enough to prevent “Mallory” from accessing the encrypted drive?

I use truecrypt to encrypt one of my drives and I would want to leave the computer running processes that use information of that drive while I'm not home, I've tried suspending it but everything ...
0
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1answer
34 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 ...
3
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0answers
50 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 ...
1
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2answers
119 views

LXD,LXC containers security

I just want to know dose the Linux containers (LXD) provide security? Such that if on container get infected with a virus will that effect the entire system (kernel+other containers) Or it will ...
0
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1answer
41 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 ...
5
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1answer
318 views

Is there a security risk if a password can be reset easily?

was just reading up on changing password complexity and I stumbled upon this: https://help.ubuntu.com/stable/ubuntu-help/user-forgottenpassword.html Isn't that a big security risk? Assuming ...
11
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2answers
4k views

Yubikey Two-factor Authentication Full-disk Encryption via LUKS

I recently acquired a Yubikey Neo - a nifty little hardware second factor authentication device. It's primarily intended for use with One Time Passwords, and the emerging U2F protocol - but since ...
6
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1answer
68 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 ...
1
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1answer
19 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.
0
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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 ...
0
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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 ...
0
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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 ...
0
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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 ...
0
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1answer
26 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 ...
0
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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 ...
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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. ...
5
votes
3answers
7k views

Disable interactive SSH at user-level

I connect to a server I don't control via SSH. I use public key access and don't need to be able to connect with a keyboard-interactive password. I would like to disable keyboard-interactive access ...
4
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1answer
33 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 ...
20
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2answers
25k 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, ...
0
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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 ...
1
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1answer
67 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 ...
1
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0answers
65 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 ...
1
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1answer
59 views

Remove string “please enter passpharase for disk…”

I traveled to Australia it seems they didn't like my face or I looked suspicious since they made me turn on my laptop and when ubuntu encryption password popped up they asked me for it, nothing to ...
2
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1answer
81 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 ...
6
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2answers
155 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 ...
25
votes
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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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 ...
3
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2answers
49 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 ...
2
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3answers
531 views

Is it possible to configure Ubuntu as a software firewall?

I have some systems running on Ubuntu in the private IP range 192.168.2.0-255 . These systems are connected to a switch and the switch is connected to the ISP's modem. Neither the switch nor the ...
4
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4answers
96 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 ...
0
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0answers
8 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 ...
0
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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 ...
9
votes
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 ...
78
votes
11answers
79k views

How to harden an SSH server?

What measures can/should I take to make sure that security around my SSH server is absolutely impermeable? This will be community wiki from the start, so lets see what people do to secure their ...
2
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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 ...
14
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1answer
35k views

What are ICMP redirects and should they be blocked?

After enabling ufw and the Tiger security auditor, I see warnings saying: The system accepts ICMP redirection messages What are ICMP redirection messages? Should they be disabled for security ...
1
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1answer
32 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 ...
1
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3answers
282 views

Should the root / have 777 permission?

Most of the contents is 755 though. Is this a problem?
3
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1answer
655 views

ClamTK Anti Virus will not run on Ubuntu 15.10

I have a laptop running Ubuntu 15.10. To protect myself, I have tried downloading and installing ClamTK. It does this without giving any error messages but it doesn't open. I tried on a second ...
2
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4answers
153 views

Is there any way to verify a Ubuntu iso or hashsum?

Neither the iso nor the hashsum is available via https. Is there any way to verify you're not getting man-in-the-middled?
1
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0answers
22 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 ...
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votes
1answer
189 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 ...