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Questions tagged [security]

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

2,617 questions
Newest Active Bountied Unanswered
413 votes
10 answers
486k views

sudo apt-get upgrade installs all updates, not just security updates. I know that I can use Update Manager to select only important security updates, but is there a way to do this from the command ...
crenshaw-dev's user avatar
  • 33.1k
348 votes
9 answers
183k views

I see a lot of interesting programs out there that can only be obtained by adding a "PPA" to the system but, if I'm understanding correctly, we should stay within the official "repositories" for ...
Rob's user avatar
  • 13k
245 votes
11 answers
227k views

Is there a way to make sure that a deleted file can not be recovered? As you know, deleting a file by pressing shift-del or using trash doesn't mean that file is gone forever. It resides somewhere ...
user avatar
228 votes
2 answers
616k views

I installed ClamAV via Terminal (Ctrl+Alt+T) with: sudo apt-get install clamav but how can I scan for viruses?
BuZZ-dEE's user avatar
  • 14.7k
226 votes
22 answers
179k views

I've often come across posts on forums or other websites where you see people joking in such a manner about running/logging in as root as if it's something awful and everyone ought to know about it. ...
Mussnoon's user avatar
  • 5,236
185 votes
2 answers
202k views

I want to install Python 3.9 on my Ubuntu 20.04, and all tutorials I can find include a step as follows: sudo add-apt-repository ppa:deadsnakes/ppa I am concerned about security. I've looked into ...
Pedro A's user avatar
  • 2,063
177 votes
3 answers
171k views

What are the main differences between PGP (Pretty Good Privacy) and GPG (GNU Privacy Guard) in relationship with security in Ubuntu and Launchpad?
Luis Alvarado's user avatar
  • 218k
158 votes
4 answers
210k views

After the BEAST attack and Heartbleed bug, now I've heard about a new vulnerability in SSL/TLS called POODLE. How do I protect myself against being exploited? Are only servers or also clients affected?...
gertvdijk's user avatar
  • 69.8k
153 votes
6 answers
127k views

As of today, a bug in OpenSSL has been found affecting versions 1.0.1 through 1.0.1f (inclusive) and 1.0.2-beta. Since Ubuntu 12.04, we are all vulnerable to this bug. In order to patch this ...
Lucio's user avatar
  • 19.3k
147 votes
3 answers
177k views

ændrük suggested a reverse connection for getting an easy SSH connection with someone else (for remote help). For that to work, an additional user is needed to accept the connection. This user needs ...
Lekensteyn's user avatar
  • 180k
142 votes
3 answers
294k views

I'd like to see if somebody has been trying to log-in by brute-force into my Ubuntu 12.04 server over SSH. How can I see if such activities have been taking place?
Ivan's user avatar
  • 59.1k
142 votes
5 answers
103k views

Recently, there have been news going around regarding "CVE-2014-6271" (See USN-2362-1), which is a vulnerability in Bash. How do I know if I am affected by this, how can I fix it, and why should I ...
nanofarad's user avatar
  • 21k
135 votes
13 answers
158k views

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 ...
Community wiki
2 revs, 2 users 80%
LassePoulsen
133 votes
2 answers
249k views

I'd like to allow SSH password authentication from only a certain subnet. I see the option to disallow it globally in /etc/ssh/sshd_config: # Change to no to disable tunnelled clear text passwords #...
ændrük's user avatar
  • 79.1k
110 votes
7 answers
62k views

I've been using gksudo nautilus and sudo nautilus through Alt+F2. What's the difference? They look very similar!
DrKenobi's user avatar
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