0
votes
1answer
23 views

OpenSSH: hacked before set up?

Today I tried setting up OpenSSH on my computer with the hope of being able to connect to it from a different computer at work. This was my first time attempting to use open-ssh. I did the following ...
1
vote
0answers
71 views

SSH connection failing since I changed server port number

Yesterday I changed the default ports on the server from 22 to 1993 then restarted but now I can't connect at all. I used ssh -i keyname.pem ubuntu@remotehost to connect then sudo vi ...
0
votes
0answers
19 views

Want to know how how secure my system is with current settings

My system is at kernel 3.15.2 Mainline. I have Enabled the firewall with all ports closed. I have very strong passwords set for BIOS, Drive Encryption, and login SSH is Disabled. I have installed ...
0
votes
1answer
67 views

changed permitrootlogin to no, but I can still login as root

I just created a new server (VM) and I setup SSH, I can login fine. I created another user account, added it to the admin group and sudo works fine. Now I want tried to disable the root login, so I ...
1
vote
2answers
34 views

Enable to connect to remote server using ssh but i can connect one remote server

When I am connecting to remote server using ip address, I can connect to 192.168.12.141, but I cannot connect to any another remote server. Example: 192.168.12.12, 13, 18 etc... How can I get ...
6
votes
1answer
779 views

How did this exploit allow write access to root owned files?

For a computer security assignment at my university I need to find and understand an exploit that works on ubuntu 10.04. I have already found and tested one on an Ubuntu 10.04 machine (that I own) ...
3
votes
2answers
92 views

Will an upgrade of Ubuntu to a new LTS change SSH host key

I have recently upgraded my computer from ubuntu 12.04 to 14.04 LTS (in one step). After the upgrade, however, I got well-known warnings like ...
3
votes
1answer
5k views

Ubuntu - saying your security settings have blocked an application from running with an out-of-date version of java

I have this new problem since 2014 begin. I cant remotely login to this enterprise network for giving them support. Its keep showing this new error. How to fix it please? EDIT:
3
votes
2answers
6k views

Help! My server has been hacked - .IptabLes and .IptabLex in /boot [closed]

I'm running a Ubuntu 6.06 dapper server and it has been hacked. I'll admit up front here that I'm a programmer and not a system administrator so even though I've worked with Unix/Linux for years my ...
0
votes
1answer
445 views

SSH: Dynamic DNS vs Port Forwarding

I recently set up SSH on my newly installed ubuntu, and already set up public key authentication and know that it works properly remotely on my local network. Now I decided that I would make it ...
3
votes
1answer
119 views

What can a user do without sudo?

I'm setting up a server and want a user to only have access to his own files. I do a regular adduser command: sudo adduser username And give the user a password. Then I log in to it via ssh and see ...
0
votes
1answer
143 views

Can the admin of a SSH server monitor internet traffic?

I use SSH Tunnelling + socks4/5 to browse securely, but a certain question came up in my mind, can the administrator of that SSH server monitor my traffic? like see which websites I am visiting, ...
1
vote
0answers
364 views

fail2ban block retry count always changes

As title mentions clearly, fail2ban block retry count always changes. I set all retry counts to 3; but sometimes it blocks me after 6 or 7 retries. How can set its behavior a constant value? I added ...
2
votes
1answer
3k views

How to use rsync via ssh with rsa key passphrases?

How can I use rsync with passphrases? All googled "solutions" i found use passphrase-less keys which seems no real option. i am runnning 2 ubuntu servers 12.04.2 LTS.
0
votes
1answer
5k views

Restrict SSH Access to Specific IP for User

My /etc/ssh/sshd_config file has a line like: AllowUsers jim@11.22.33.456 If I want to allow jim to use another IP addresses, how do I specify it? Does it take the form of a comma separated list? ...
6
votes
1answer
546 views

How to set up an rsync backup to Ubuntu securely?

I have been following various other tutorials and blog posts on setting up a Ubuntu machine as a backup "server" (I'll call it a server, but it's just running Ubuntu desktop) that I push new files to ...
-1
votes
2answers
340 views

Secure your private gpg and ssh keys from other people accessing ssh

There is a person A and person B, other of them has each other ssh public key, so that means they can access each others shell. now they can access each others private ssh and gpg private keys. and ...
3
votes
3answers
385 views

SSH key plus password

I see there are continuous attempts to login into my computer via ssh using usernames, like joan florin root from 60.169.22.118, -how can I forbid ssh access and only allow it to users with specific ...
5
votes
2answers
771 views

Precautions during SSH [duplicate]

Possible Duplicate: How can I audit users and access attempts to SSH on my server? I recently had to give away my Ubuntu 12.10 root password to one of my friends so that he could SSH into ...
47
votes
2answers
44k views

How do I keep track of failed SSH log-in attempts?

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?
2
votes
1answer
206 views

How do I create one user without key authentication?

I've completed the following steps: I have configured Ubuntu server with Key authentication and it is working fine. I have disabled password authentication for key authentication to work. The server ...
1
vote
1answer
209 views

Having an Issue in restricting length of password

I am trying to place a restriction on my ssh box to require a password of a min. length of 16 character and a max. of 30. I was following the Password policy section, in the official user ...
48
votes
2answers
5k views

How can I use a passcode generator for authentication for remote logins?

I would like to strengthen the authentication of my SSH logins by adding another factor: a passcode generator device, or a passcode generation application on my mobile phone. The only obvious options ...
0
votes
1answer
230 views

Is there any mechanism that blocks connections by IP address in a default 11.04 installation?

On a default installation of 11.04 desktop (running inside a VM), I'm getting a strange phenomena in which occasionally some people can't ssh into their account in the regular way (they simply get a ...
15
votes
2answers
18k views

How can I allow SSH password authentication from only certain IP addresses?

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 ...
4
votes
2answers
1k views

What is the best way to secure my EC2 server in regards to the SSH?

I have a Amazon ec2 instance, and was curious on if I should change the username (the default is ubuntu) or not? Since you need a public SSH key in order to access the server, I don't think you do, ...
4
votes
2answers
3k 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 ...
8
votes
1answer
2k views

How can one unlock a fully encrypted Ubuntu 11.10 system over SSH at boot?

In previous versions of Ubuntu, and current versions of Debian, you can unlock a fully encrypted system (using dmcrypt and LUKS) at boot time over SSH. It was as easy as: Installing the encrypted ...
25
votes
2answers
29k views

How to create a restricted SSH user for port forwarding?

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 ...
1
vote
1answer
240 views

Certificate logins to servers

I have some ubuntu cloud servers running and has the iptable rules applied on them to allow only few ip addresses to connect via ssh. I know how to generate SSH-key for connecting to server ...
1
vote
2answers
854 views

How to prevent seahorse from asking for a passphrase?

I've created one password-protected RSA key to access my remote server via ssh using key-based authentication and added it to seahorse using ssh-add. I would like to prevent seahorse from asking me ...
12
votes
5answers
19k views

How to secure ubuntu server from bruteforce ssh attacks?

I have my passwords secure, but I heard people complaining about perfomance of a server going down drastically when a bruteforce attack is taking place. How can I secure my ubuntu 10.10 server from ...
8
votes
2answers
5k views

What does “pts/” in the output of w mean?

When I run w - to see who is logged on and what they are doing, i see this: USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT user tty7 :0 08:14 10:32m ...
17
votes
2answers
656 views

Accidentally typed password in username input, any logs to clear?

I have accidentally typed my password in SSH's interactive username prompt. Are there any log files that I should clear?
10
votes
1answer
2k views

How to give ssh access to trusted friend?

I've got a friend that I trust enough to give ssh access to one of my servers. To this end, I've created a user account for him. The box is accessible by key authentication only, not passwords. ...
4
votes
4answers
460 views

I've setup SSH Key login, but want to avoid a passphrase

I've set up a passwordless login to a friend's computer and everything works very well. I've even edited my ~/.ssh/config to add his hostname and my username. So I just type ssh friend and it ...
1
vote
1answer
267 views

DenyHosts SERVER_SYNC option, call for anecdotal reports

I'm securing my ssh server with DenyHosts, and decided to dig into DenyHosts' configuration to make sure things looked good. There's an option called SERVER_SYNC, that makes an xmlrpc call and seems ...
12
votes
6answers
10k views

How can I audit users and access attempts to SSH on my server?

I've had a few security problems with a server of mine, a few SSH users have been setting up fires aka giving problems. I would like to: Track user logins and logouts Track activity of these SSH, ...
39
votes
9answers
24k 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 does to secure their ...
8
votes
2answers
5k views

How to set up an Ubuntu 10.04 machine to accept ssh requests only from within the local network?

I am about to install 10.04 (from bare metal to replace 9.04) and I want to set it up so that I can shh into the machine, but only from other machines on my local network. (I.e., I want to reject all ...
12
votes
2answers
3k views

Disable password access through SSH?

I'm setting up a server for backing up my desktop box remotely. I want to prevent remote password access to the server, permitting only users with private keys (AKA my desktop box) to access it. How ...
27
votes
8answers
9k views

How to set up a headless server?

I have a ubuntu development server at work. It is an old rack server that is located somewhere in the company's dungeon, where nobody ever goes. The only way it can work is as a so-called headless ...