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

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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: https://bugs.launchpad....
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2answers
166 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= rhost=188....
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2answers
73 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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2answers
528 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
33 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
383 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
2k 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 ...
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1answer
167 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 ...
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1answer
597 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 ...
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1answer
73 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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52 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 ...
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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
107 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
52 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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1answer
79 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?
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1answer
43 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
81 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
37 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 ...
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1answer
122 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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19 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 ...
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0answers
100 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 ...
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1answer
224 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 ...
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3answers
564 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 ...
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1answer
51 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 ...
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0answers
37 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 ...
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2answers
126 views

How to automate the process of checking an Ubuntu ISO SHA256sum

I know that I can get the SHA256sums (and MD5sums) from http://releases.ubuntu.com/ as they are provided now within the folders, but is there any way of automating the checking process so that the ...
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1answer
198 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 ...
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1answer
152 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 ...
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1answer
324 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 ...
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1answer
213 views

Why ntpd needs an open port?

On my Ubuntu system I have activated the 'Time Synchronization via Internet'. Because of that the ntp daemon gets started. What I don't understand: Why needs ntpd an open UDP port 123? Actually, I ...
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1answer
153 views

What does these logs means? (DHCPREQUEST)

I'm using Ubuntu 14.04 LTS as my OS. For safety purposes, I'm always checking the logs to see any strange thing. Today, I have found something that (probably) never happened to me: Jun 11 23:33:59 ...
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1answer
89 views

Suspected rootkit, what should I do?

I inherited ubuntu 12.4 server and I want to check it for possible rootkits/modifications. Is there a way to test all executable/library files for modification (test if currently installed files are ...
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1answer
40 views

How to deal with this untrusted program

The program is IPFS. I do not fully trust the program, how should I keep it from making changes to my system outside of its designated folders?
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1answer
302 views

What are the features in Snappy Ubuntu that make it more secure than the normal Ubuntu?

I am thinking of using Snappy Ubuntu for IoT application. Security is important in IoT. What is the difference between Snappy Ubuntu and the normal Ubuntu that makes Snappy more secure compared to ...
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1answer
159 views

How to exclude a specific folder from search in Synapse?

I added excluded folder to Security & Privacy settings and I followed this instructions but all of them seem to be working only when using Unity Dash search. Inside System and Home Dir. I could ...
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2answers
45 views

When would my application need to run with privileges?

One way of making sure an application is less prone to attack is to make sure it runs with the least privileges required (user mode preferred). I've only usually programmed for Windows using the .NET ...
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1answer
957 views

can windows virus affect Linux machine through wine? [duplicate]

When we use wine on Linux PC windows Virus can affect folders of wine? I think may be not; But I still Confuse about that. What is accurate answer? Wine is emulator of windows then some question ...
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1answer
114 views

Ubuntu Phone prevent text messages from lock screen

On my Aquaris Ubuntu Phone, text messages quickly pop up on the lock screen. As I consider this a serious security issue, is it possible to hide any messages from the lock screen? Thanks for any ...
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1answer
26 views

Unresolvable problem [duplicate]

An unresolvable problem occurred while initialising the package information. Please report this bug for the 'update-manager' package and try to include the following error message: 'E:Malformed line ...
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1answer
4k views

Could not load host key: /etc/ssh/ssh_host_ed25519_key in /var/log/auth.log

I have an Ubuntu 14.04 instance running on AWS. I was browsing the auth logs (/var/log/auth.log*), and noticed the following line appearing: Could not load host key: /etc/ssh/ssh_host_ed25519_key ...
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1answer
2k views

How to show all files created on a specific date?

On 16/05/2015 at 17:18 I visited a malicious website. And I suspect a drive-by-download, so I want to check my machine to see since that time in order of creation which files have been created or ...
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2answers
98 views

What is this and how can this happen? Is this a security issue or can it be a virus?

From the last 3-4 days, my laptop has started becoming much laggy when I'm working on Android Studio or if it is just running in the background. So, today again I was working in Android Studio. My ...
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1answer
174 views

How to enable unhide in rkhunter

I have installed rkhunter with: sudo apt-get install rkhunter And even though I have enabled all test, when I run: sudo rkhunter --check --sk If I check in the log file, I see this about the ...
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1answer
70 views

Upgrade hardware enablement stack but retain kernel

Ubuntu 14.04.01 According to official documentation, upgrading the hardware enablement stack in Ubuntu to utopic-lts upgrades the kernel and xorg. I only want to upgrade xorg to correct a display ...
2
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1answer
297 views

Installing Tripwire

I just installed a fresh version of Ubuntu 15 and while I installed it I did not connect to the Internet. I have read you should install tripwire first thing after a fresh install and before you even ...
2
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1answer
417 views

Mumblehard Malware on my Server?

this morning, I watched a monthly webinar about IT-Security. One of the actual topics was the malware "mumblehard". This malware makes your server to a part of a botnet and sends spam via email. The ...
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0answers
89 views

Cannot download security updates in Lubuntu 14.04 LTS

Software Updater offers Security Updates--Ubuntu Base--61.9MB. I click Install now and authenticate. Screen shows "Failed to download package, check your internet connection'. There is no problem with ...
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1answer
81 views

Is running packages from Ubuntu universe more risky than running the same packages on Debian? [closed]

I am running Ubuntu LTS Server. Are there any concerns with security patching of universe packages? I mean am I in risk of running vulnerable system if having universe packages when compared to the ...
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1answer
3k views

.android Folder and adbkey Files

Today I discovered a folder in my home directory with the name ".android". Inside the folder are just two files, "adbkey" and "adbkey.pub". I have searched around and have found out that adbkey.pub ...
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1answer
130 views

Set password security with pam.d (urgent homework)

I am trying to change the password security check. I would like to set rules for the password when adding a new user. Here is the content of my /etc/pam.d/common-password file: password ...