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

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21 views

heavy write to disk activity as soon as I turn on computer

Can someone tell me if something nefarious is going on? I recently had to wipe my drive (losing all my data) and do a reinstall. So, I've been using the new 15.04 for 3 weeks without incident. But I ...
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0answers
4 views

LUKS encryption, switch from passphrase to keyfile

Using LUKS encryption, I set it during the Ubuntu installation. I entered a passphrase. But now I want to use a keyfile and I dont manage to find the right process to. How can I make the switch ...
4
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1answer
32 views

Which unattended-upgrades system takes precedence and how?

I've just run into an answer that has made me question how the unattended upgrade system works. There seem to be at least two systems on my computer: unattended-upgrades with ...
2
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1answer
41 views

Security: Automatic updates - automatic or not?

I am using kubuntu 14.04.2 I have updates set to download and update automatically for where there are security updates - yet the security update for Adobe Flash was not automatically installed when ...
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0answers
12 views

hot to get the strict and targeted policy for selinux

I am learning how to use selinux as a step to develop in the security subsystem but the book I am using requires targeted and strict policy I have ubuntu 14.04 and I am not willing to use any other ...
2
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1answer
48 views

Ubuntu 14.04 LTS Security?

[Ubuntu 14.04 on 2014 Retina MacBook Pro 15" using rEFInd] (ThomasW's Why is everybody so concerned about etc/passwd? link addresses my initial comments about accessibility to passwd and other files, ...
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2answers
17 views

Recovery ubuntu encrypted home

If someone gets physical access to my pc, mounts my ubuntu and changes my user password (e.g. in the shadow file). Will he be able to log into my account and decrypt my (encrypted) /home partition? ...
3
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1answer
29 views

LUKS encryption, header on a dongle USBdrive?

I am going to install Linux the LUKS/LVM way, in order to have an encrypted disk. In addition, I would like to put the header and passphrase in a USB Key. Thus, instead of entering the passphrase, I ...
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2answers
3k 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 ...
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0answers
24 views

Strange ping result?

I'm new here. I just would like how this is done? Here's the scenario of events: I was pinging randomly some no-ip adresses(i just imagine an adress and ping it) Every thing is fine, most of ...
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0answers
14 views

Is X11 on Mac dangerous, harmful in anyway? [closed]

Is there a security risk. With downloading X11 to use wireshark on a Mac. Can an attacker Exploits any vulnerability's to hijack. Or can I get a virus with X11? Or is it safe. People who believe a ...
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0answers
40 views

Security issues and Privacy [closed]

How can a linux user safeguard or harden their system against firmware vulnerabilities and how does Gnu/Linux handle such?
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8 views

Setting up firewall for my hosting

I am having an Ubuntu 14 instance installed in Amazon Cloud. In there, I have setup apache2,tomcat7, and phpmyadmin. Any request to port 80 will be forwarded to the tomcat based java application. ...
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1answer
69 views

Does Canonical collect data about how I use Ubuntu?

Does Canonical collect any user data about me or my habits during my use of Ubuntu? And if so, how can I stop this data collection?
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2answers
31 views

Is sharing a mounted USB drive on Samba without a password a security risk?

At my low level of expertise, the only way I can share a mounted external drive from Ubuntu 14.04 to Windows computers in my house is to use the Samba GUI to share it, then edit smb.conf to add "force ...
1
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1answer
38 views

Ubuntu Server minimal package

What is the best why to install an Ubuntu Server image with the minimum possible of package ( no default, no extrat ) that can only allow ssh connection to it and nothing else.
4
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3answers
290 views

How to stop firefox from downloading files in public computer to its Home/Download folder?

I work in IT-department and we have a situation. We have public computers installed in city library and they are using Ubuntu 12 kind off kiosk operating system. People are opening and downloading ...
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0answers
73 views

How to permanently block adult content on Lubuntu? [duplicate]

How to block adult and nudity content in Lubuntu? I block 18+ adult content on my home PC using K9 web protection when I use Windows XP. I simply download the file .exe. Get license number via ...
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2answers
81 views

Ubuntu 12.04, PCI, and CVE-2015-5352

PCI compliance will fail when the CVE-2015-5352 vulnerability is present. OpenSSH 6.9 fixes this vulnerability, but Ubuntu 12.04 has not been patched. What is the best way to address this ...
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0answers
101 views

virus in ubuntu 14.04 adware malware spyware…?

I am using Ubuntu 64 14.04. I have used Ubuntu for many many years, and today I got malware or spyware, although I don't really know what it is. I use chrome Version 44.0.2403.89 (64-bit) the latest ...
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0answers
25 views

Ubuntu Touch: How to view own error reports

in March I reported a bug here on ask ubuntu that the setting not to send error reports to Canonical in the system settings is useless so far as it doesn't safe what you choose: ...
3
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2answers
17 views

system log question- auth.log

I'm pretty new here. I was looking at my system logs and noticed this: Jul 21 00:57:47 htpc sshd[13001]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= ...
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1answer
27 views

How to get Firefox to only load images from trusted origins

As you can see by the name, I am paranoid, and I realise that I can get something malicious on my machine through looking at an image. I have disabled my browser's cache, but this still only limits ...
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0answers
31 views

Not sure if I should report a potential secuirty problem

I have been seeing potential suspicious activities on my computer that I think may be linked to what they call clickjacking. I noticed some suspicious activities from apparmor reporting stuff like ...
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vote
2answers
48 views

How do I restrict a specified SSH user to connect only from one IP or hostname?

I have a monitoring server that requires the SSH connection details of a non-sudo user account of each box it monitors. Is there a way that I can configure a specific user account such that it can ...
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0answers
30 views

Is it possible to maintain server from account without admin rights?

I am wondering how should I proceed if I want to hire someone to maintain my Ubuntu server. If I give admin rights to his account he may do a lot of damage if he decides to, but if I don't give him ...
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2answers
29 views

Nmap Logs Question

I recently did an Nmap scan of my network with the ZenMap GUI tool on my Ubuntu install and I got a weird scan result; well in my opinion anyways.. Even though I am using Ubuntu 15.04, for my host, I ...
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4answers
1k views

If I follow instruction from blog/web, is that always safe? [closed]

I am new with Linux especially Ubuntu. When I don't know how to do something with this OS I search on web and AskUbuntu and always have the answer. But sometimes it's not a great answer nor complete ...
0
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1answer
124 views

How can I circumvent MitM attacks on hostile networks? [closed]

I suspect my local network is not as secure as one might like; I believe its administrator may be trying to intercept and sniff my traffic. Are there any ways to prevent Man-in-the-Middle attacks ...
0
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1answer
75 views

How to configure UFW for a basic desktop / laptop? [closed]

Reading this answer about enabling UFW, I understand that a computer without firewall can be safe in my local network, but this same safe configuration on a laptop used outside of my local network ...
0
votes
1answer
28 views

Why is su disabled from guest sessions?

From guest you can't sudo or ssh. Why I can't sudo is simple. But why can't I su? What is it that su provides that ssh to the user@localhost wont? The reason for this question being my other ...
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0answers
30 views

How to prevent ssh on local host?

I came to know that on ubuntu, sudo and su is not available in a guest session because of security concerns. But all I need to do, if I have the login credentials of a user in the sudoers list is too ...
2
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2answers
1k views

What is CVE-2015-1793? Does it affect me?

Apparently a new bug has been discovered in OpenSSL, it is being called as Alternative chains certificate forgery (CVE-2015-1793). Canonical already declared the versions of openssl that are not ...
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2answers
41 views

Apparmor is not functioning

When I check the status of Apparmor, I get this: xubuntu@xubuntu:~$ sudo apparmor_status apparmor module is loaded. 0 profiles are loaded. 0 profiles are in enforce mode. 0 profiles are in complain ...
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1answer
43 views

How to file a bug report against Ubuntu in general?

I am wanting to file a bug report against Ubuntu in general, because I have noticed that the Ubuntu security hashes provided, are only MD5sums, and as for security reasons MD5 is being phased out, it ...
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0answers
16 views

dpkg-sig produces no output

Installed dpkg-sig to verify a package - it produces no meaningful output, just "processing" and then no result either way (signed or not signed correctly). Example: $ dpkg-sig -c ...
5
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0answers
35 views

Kernel security levels in ubuntu

Is there any ubuntu equivalent of BSD Kernel Security Level? If yes, how can one change the security level?
2
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1answer
22 views

What is a (reasonably) secure and automated way to backup my mysql database using (any) free cloud/online services?

I have a mysql database that I use for personal devlopment. I would like to back-it up online using any free (in cost) online storage. (dropbox, google-drive etc...) I am assuming a shell script ...
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0answers
14 views

xubuntu suddenly asked me for my password to mount an USB flash disk. Is this normal?

It never asked for it before or after and this one time was after the flash disk was inserted in an untrusted computer. I don't remember the message exactly. Is it possible malware got on the flash ...
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0answers
24 views

Can i run apache 1 / 2 as root?

I am hoping someone can confirm if apache 1 and / or 2 could be run as root if the user wishes it? There are previous questions around this, where people say "no you don't want to do that" and don't ...
2
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1answer
62 views

Can malware enter Ubuntu?

I have a desktop computer with Window 7 system and Ubuntu (installed by my boyfriend). Last week when I shopped online on Win7, I accidentally caught Eye Perform ads in Firefox. I Google and found ...
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0answers
12 views

How do I add an existing ubuntu user to a new domain?

Our organization is making some changes in their security model and they have created a domain server with which each machine would be linked. For this, they have created a new user on my laptop which ...
0
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0answers
33 views

Does Ubuntu store passwords from failed login attempts?

This is probably a stupid question, but if I type in an incorrect password while attempting to log into my account, does that password get stored anywhere? Assuming that I don't have any third-party ...
1
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1answer
29 views

Locking down an apache server - Prevent '/' page from being visible to all

I first installed Apache as part of a ZoneMinder setup. I then added to the server with an ownCloud setup. All this is only accessible to LAN or to WAN-through-ssh and that part works great. I now ...
9
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3answers
475 views

sudo permission doesn't time out durring apt-get upgrade

Consider this: You type $sudo apt-get upgrade and get a list of things that need upgrading with a "Y\n" confirmation. before you can read the list, and type "Y" or "n", the phone rings, or your boss ...
0
votes
1answer
21 views

Can I make the Windows folder require a password to access it? [Edit/change or add flder and data]

Recently, I was thinking that while running wine an application that contains a virus can inject into the windows folder. I don't know if this is possible, but it would be nice to make the Windows ...
0
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0answers
27 views

How would I securely connect to a smartphone?

I have got Ubuntu 14.04 LTS and a smartphone with no brand name of any kind. How do I connect the smartphone to my computer securely? The OS is unspecified. it looks like android. I am worried ...
1
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1answer
48 views

launch ipython but not like root

ipython is launched like root (UID); ok, but I need that after ipython cann't run and don't allow, script/code that can gain root privilegies. eg I launch ipython, ok the UID is root. And in my ...
0
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1answer
25 views

Stateful Packet Inspection on Ubuntu?

By default Ubuntu doesn't have open ports (exceptions: Avahi and dhcp). Assuming that my system is connected to the internet by direct way (no hardware firewall used): If I am sending a UDP packet to ...
0
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1answer
31 views

Block all but one ip address

I need to allow access to only one IP address and block the rest, so I wrote the following: sudo iptables -F sudo iptables -A INPUT -s ipaddress -j ACCEPT sudo iptables -A INPUT -j DROP sudo iptables ...