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

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How to find malicious packages?

According to one of this question's answers, dpkg --get-selections | grep -v deinstall will give me the list of installed packages. I ran it but the output was almost 3000 lines long. How to audit it ...
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1answer
8 views

Ubuntu Mozilla Security, do I need this? General questions

I was searching for info on enabling/disabling javascript in firefox, some pages I need to have it function and without the java they're broke. I came across this and was wondering is this something ...
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1answer
17 views

Interpreting results from rkhunter

I'm making some scans on my computer because I have a suspect of being hacked. All of this started because I was getting occasionally this message at start-up. When it showed up, my internet didn't ...
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2answers
19 views

How to edit /etc/default/ntpdate and prevent ntpdate from ever running without uninstalling

Since both ntpd and ntpdate rely on ntp servers, and since the Ubuntu repos have yet to complete an update of ntp to 4.2.8p4 (the version recommended by ntp researchers), I expect this means that both ...
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0answers
8 views

Restricting the Number of IP/TCP Connection Request Per Second Using Ubuntu Sever

I know what type internet connection my machines have and how much CPU/RAM they are using. So Is it possible to restrict the accepting number of IP/TCP connections per second at the OS level, before ...
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14 views

Run file when USB device inserted

I want to implement a strict policy of nobody being able to insert any USB device into my laptop. If someone inserts a memory stick, keyboard, light etc... into any USB PORT (while the computer is ...
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0answers
12 views

Securing a port in ubuntu with username and password

I have Elasticsearch running on 9200 port.I want to secure it and I dont want others to access the data stored in the index in ElasticSearch. How do I secure the port and limit its access using ...
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1answer
31 views

With secure boot disabled, is there long term vulnerability to malicious code (on 14.10 and 15.04/Win multiboot setups)?

In a nutshell: is it really a good safe idea to leave Secure Boot disabled? I have two laptops with LinuxMint,Xuntu, Ubuntu 14&5 Win 10 and Win 8.1 between them. Grub 2 works fine with /,/boot ...
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2answers
110 views

Email on failed login attempt?

I was wondering if it is possible to set it up in such a way that on a failed login Ubuntu will send me an email? And of course if the computer is not connected to the internet when the attempt ...
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0answers
10 views

encfs reset settings to standard

I do not correctly identify the customizations when it first installs. Encrypted data is now not displayed. How to reset the settings to standard?
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2answers
416 views

How can I further secure my system using 2 factor authentication?

The title pretty much says it. I have been hearing more about 2 factor authentication, one-time passwords, hard-tokens, and other improved security features. With the decreasing security of using just ...
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4answers
52 views

What is the reasoning behind hiding characters when entering the sudo password?

When entering the sudo password, the • characters are hidden. Apparently the • are omitted for better security. They seem secure enough to me, and I don't see why they're not used. I think I'm ...
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2answers
39 views

Is firefox safe to use on Ubuntu/Linux? [closed]

While using Firefox on Ubuntu, I frequently run into warnings from various sites (recent examples: when checking gmail, www.hitrecord.org), that inform me that I am using an outdated/unsupported ...
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33 views

UFW ACCEPT Problem

I'm having problem with UFW. If i block like whole /24 network becouse lots of bruteforcing etc. coming from China / Korea or somewhere. They still get to open ports. If i have, lets say port 443 ...
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1answer
36 views

Of what help is SE linux to me?

i am new to Linux. I have heard about SE linux ... how does it work with Ubuntu and what can i do with it?
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3answers
1k views

Unsupported Ubuntus - is it safe to continue with them?

I'll try to be as clear as I can about this, hoping to get clear answers. I have Ubuntu Studio 15.10, which is not an LTS version, and will only be supported till July 2016. Does that mean there ...
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0answers
15 views

Whats the diffrents between chkrootkit and rkhunter? [on hold]

I've heard about the famous linux anti-rootkits called chkrootkit and rkhunter I use rkhunter with clamav but do I need to use chkrootkit also or is that a different story?
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17 views

Does ubuntu comes with any encryptions programs by default [duplicate]

Is there any preinstalled encryption program in linux that I can use to encypt my data or do I need to install a third party program
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2answers
27 views

Auto unlock keyring on auto login without leaving password unencrypted

So I keep getting this unlock keyring popup when I login to Ubuntu automatically. There is a fix here: How can I stop being prompted to unlock the 'default' keyring on boot? I have been googling ...
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1answer
43 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 ...
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0answers
13 views

How to only allow a file to be opened or executed by certain application(s)?

Let's say that I've got a security application (or something which I just don't want any old application or user to have access to because it is very important and if the wrong guys had access to it ...
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1answer
36 views

Automatic kernel security updates no long being installed

A while back my /boot partition filled up on my Ubuntu server 14.04 install. This caused an automatic kernel security update to fail and be in a partially installed state. To fix the problem I removed ...
15
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2answers
4k views

New Zero-day exploit reportedly found affecting Linux/Android (CVE-2016-0728)

Russia Today reports (20 January 2016) that there is a new zero-day exploit that has been discovered affecting Linux and all Linux-based OSes for computers and phones. What is the deal; how does it ...
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0answers
7 views

cureent Kerberos password specifications

Current kerberos password, there must a certain number of used charecters or length...I keep getting, that doesn't work please try again from my welcome screen, does anyone know the specifications?
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1answer
37 views

Secure browsing

I would like to hear from you suggestions, how to improve security during browsing. Let's say that I am going to use Chromium. With this extensions: Web of Thrust (to be noticed, if i visit bad ...
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0answers
18 views

NTP question on ntpdc -c peers

I just started learning networking. I recently installed ntp on Ubuntu 14.04 running in Virtualbox on OS X. I was just trying to understand how it works. so when I executed ntpdc -c peers command in ...
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14 views

Everything in syslog has been removed! Security risk?

I am new to Ubuntu. I've only been using it for a few weeks. I was wondering; does Ubuntu delete the logs after a while? My syslog was full of logged events this morning, but when I checked it now, ...
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1answer
62 views

Linux overwriting RAM with zeroes on free()

I was just wondering if it is possible to tell Linux/Ubuntu to overwrite freed memory with zeroes before letting the next application allocate it? If not, why isn't this possible? I know that ...
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1answer
32 views

Ubuntu : Disable access to file-manager, keyboard,mouse(Touch screen available) for guest account

I am looking to configure Ubuntu(Any version, new installation) for presentation in which I would like to do the following things : Automatic guest-login at startup. Completely disable ...
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2answers
10 views

Are ssh keys generated individually by Ubuntu Server LTS 14.04 setup?

Let's assume freshly installed and updated&upgraded Ubuntu Server 14.04 LTS with ssh server. Does installation scripts generate new ssh keys for each installation (so I am safe having unique ...
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0answers
10 views

Maintenance/Security of installed Apache Tomcat 7.0 on Ubuntu (14.04 LTS) “Trusty Tahr”

I recently installed Apache Tomcat 7.0 on my "Trusty Tahr" linux machine. I wanted to know if I should be preforming any type of maintenance or adding any type of security measures to my system? I'm ...
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1answer
32 views

What to do about a false positive in clamtk

I am getting a message from clamtk antivirus after running a scan on the download folder the result said 10 viruses found how can 10 viruses be found if nothing in the download folder but some files ...
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3answers
66 views

Help I can't update clamav!

I was updating the clamav antivirus defenitons with the sudo freshclam command and the output was ERROR: /var/log/clamav/freshclam.log is locked by another process ERROR: Problem with internal ...
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1answer
57 views

What are the alternative to clamtk

I installed the antivirus clamtk/clamav, the installion went well, but I can't run the program. I tried a terminal, but that did not work. The result was if I typed sudo clamtk nothing happen, but if ...
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1answer
37 views

How to know that my ubuntu system is clear from bad file? [closed]

How to know that my system have been accessed through by backdoor and how to know there is rootkit, malware or trojan in my ubuntu system.
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1answer
64 views

Redirection to ad pages in browsers

I have a serious problem when visiting web pages, with anything in any moment, as you can see in the screenshots. photo1 - ubuntu-es | photo 2 - ask ubuntu | i.imgsafe.org/373b693.png | ...
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3answers
859 views

How can I force sudo to always ask for a password after waking from suspend?

Say I execute a command with sudo, then if I use sudo within the next 15/5 minutes (not sure how long it remembers me for) it won't prompt me for a password. It will only prompt me again if I haven't ...
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2answers
21 views

Run service with previledges of another user?

I want to host a CouchDB but heard that it might be wise not to run it as a root but create an own user for that with little privileges as possible. How can I achieve that? When I just install ...
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1answer
25 views

Protect Ubuntu system from MSFvenom attacks

I have been reading about MSFvenom and its usage as a tool to attack devices connected to a common network (for example, see here and here). Kali is a well-known Linux distribution that implements ...
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0answers
25 views

Security risk of shared folder outside home folder

I recently set up a shared folder over my network sharing files that are located on hard drives attached to my Ubuntu machine with an Android home theatre system. Since I am NOT the owner of the ...
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1answer
28 views

Any CA Cert trusted by default on ubuntu?

I understand I can copy the CA cert to certain location and run script update-ca-certificate to import CA cert to the system. But I'm curious is there a list of CAs that are trusted by default on ...
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2answers
36 views

Why does Ubuntu comes with two firewalls by default?

I just realised Ubuntu comes with two firewalls by default iptables and ufw. But why? I mean running more than one software firewall on one computer can be insecure, that's what they say. I don't ...
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1answer
31 views

How to make a computer running on runlevel 3 ask for password when waking up from suspend in X?

I have recently set runlevel 3 as a kernel parameter instead of runlevel 5, though this has caused a little bit of a problem... Because when I execute startx and then once the GUI has loaded, if I ...
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0answers
27 views

Secure Mode Ubuntu 15.04 [duplicate]

I'm running 15.04 ("live version" from an external SSD on a Mac Pro). When Ubuntu boots, I get a warning that it's in "insecure mode." What does this mean?
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How to insert digital signature in LibreOffice documents [duplicate]

I was trying to insert digital signature in LibreOffice writer documents. I went to file section then to digital signature. After that, I couldn't insert my sign because the option was blank. How to ...
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1answer
35 views

Problem with determining “security updates”

My test machine is running Ubuntu 14.04.1. /usr/lib/update-notifier/apt-check --human-readable says that 157 packages can be updated and 81 are security updates. apt-get -s dist-upgrade | grep ...
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2answers
567 views

Is Ubuntu vulnerable to a Grub2 authentication bug?

Does this security bug affect Ubuntu? It involves pressing backspace 28 times to break into a machine. From Lifehacker: The researchers, Hector Marco and Ismael Ripoll from the Cybersecurity ...
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3answers
711 views

How to fix Secure Boot error “Image failed to verify with *ACCESS DENIED*” on startup?

When I started up my machine this morning (I have Secure Boot and UEFI only enabled) I got this error (sorry for low quality image): What does it mean by Image failed to verify with *ACCESS ...
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1answer
48 views

Which is the most secure way to connect to the office network from outside? [closed]

For working remotely, I am looking for the most secure way of logging-in to office network from outside. Being a data center, the minute chance of vulnerability issues cannot accepted. Is open VPN ...
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1answer
196 views

Chkrootkit says “Searching for Linux/Ebury - Operation Windigo ssh… Possible Linux/Ebury - Operation Windigo installetd”, should I be worried?

I recently ran sudo chkrootkit and this was one of the results: Searching for Linux/Ebury - Operation Windigo ssh... Possible Linux/Ebury - Operation Windigo installetd In my research on ...