SSH (Secure shell) is a protocol for secure communication between computers to execute remote commands, transfer data and tunnel TCP connections.

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Tunneling SSH traffic through tor [on hold]

I have encountered a somewhat bizarre issue while playing around with tor and SSH. After a connection to the server has been established the source address of the client(in this case the tor exit ...
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chroot ssh users [on hold]

I am using CentOS 7. I need to give shell access to ssh users but restrict them in a jail. I have used jailkit to set up the jail. I have copied all necessary libraries, binaries that are needed for ...
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SSH Key: Ed25519 vs RSA

A lot of people recommend using Ed25519 instead of RSA keys for SSH. The introduction page of Ed25519 (http://ed25519.cr.yp.to/) says: [..] breaking it has similar difficulty to breaking [..] RSA ...
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What stops an SSH server from MITMing logins?

When I read this question about what gets signed with the private key by the client I wondered: What stops the following scenario from happening: A client connects to an SSH server. The SSH server ...
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Is it possible to add a cipher for an sftp client? [migrated]

I'm running into an issue where a server was upgraded to RHEL 6.5, and we have automated scripts on an RHEL 5.9 install that connects through sftp and ssh commands. Now, the new server only supports ...
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113 views

Break in attempts from secureserver.net

Over the last few weeks I have seen dozens if not hundreds of break-in attempts from ip addresses which map back to secureserver.net. I know these are GoDaddy machines from the who is look up. ...
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1answer
327 views

Are there any security implications in creating an SSH key for the root user?

I've written an install script on a server to quickly set up new sites in the /srv directory. It needs to do a git clone, and has to be run via sudo in order to have the permissions to do all the ...
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1answer
90 views

Analyzing log files for forensics homework?

Suppose two users have done a murder at 6pm at Dunkin Donuts, I have got the hard disks on site, disk1 and disk2. How do I identify the time and order of each user's activities on the hard disks? ...
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38 views

Logging all traffic crossing SSH proxy

Is there a way to log SSH sessions proxied through a machine (User-> SSH Proxy -> Server (with SSH)) without modifying the SSH daemon on the proxy? I need to log all the commands as well as responses ...
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Managing multiple SSH private keys for a team

I have a medium-sized team (~10 people, but we expect to grow) that manages a set of EC2 servers on AWS (currently a few dozens, but this is also expected to grow). As EC2 requires you to have an ...
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1answer
20 views

How is composed “public host key and certificates (K_S)” in SSH_MSG_KEX_DH_GEX_REPLY message? (SSH2 key exchange)

I'm trying to implement SSH2 key exchange in Java, and having some difficulties. The RFC4419 states, that: The server responds with: byte SSH_MSG_KEX_DH_GEX_REPLY string server public host ...
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44 views

SSH: What's the difference or interplay between /etc/ssh/[host files] and ~/.ssh/[public key]

I'm new to SSH after a decade of dabbling with Ubuntu and other Linux builds. Today I successfully setup SSH, but I had a few hangups and headaches along the way. Although the system is now running ...
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1answer
102 views

someone may be doing something nasty

I have an ssh server. earlier toady, I was about to login to my server, when I got a message that said something along the lines of "Someone may be trying to do something nasty" and indicating a man ...
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95 views

Sharing a common public and private SSH keys for a cluster of machines

I guess this is way to settle an internal debate I am having with myself. In my provisioning process, I am wanting to share a common public and private ssh keys for each machine in a clusters, ...
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1answer
29 views

How to handle disk encryption for remote connection?

I have at my workstation, an ubuntu 14.04 installation with full disk encryption. I now have to travel frequently for days and am planning to ssh into this machine from my chromebook to work remotely. ...
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1answer
37 views

Things to do to ensure that data is secured on my virtual server [closed]

I'm not much of a server administrator but I'm maintaining a virtual server with Ubuntu OS where my website is hosted. I often use ssh, ftp and MySQL. As my website gets popular, I want to make sure ...
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1answer
38 views

Using Google Authenticator for SSH sessions

So I have an SSH tunnel which I use with dynamic port forwarding to the alternate http port on the client. For initializing this connection, I'd like to implement an additional verification step, ...
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1answer
54 views

How to view all SSH authorized_keys for a unix server

How would I view all the authorised SSH clients from a unix server? I know that cat ~/.ssh/authorized_keys shows authorised keys if logged in from root. Can other users set their own authorised keys ...
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Metasploit ssh_enumusers stops instantly [closed]

When I try to run the : http://www.rapid7.com/db/modules/auxiliary/scanner/ssh/ssh_enumusers using the given options besides proxies I get the output: msf auxiliary(ssh_enumusers) > run [*] ...
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30 views

Custom publickey authentication

I'm working on a REST account management system over https that should support both username/password and username/publickey authentication schemes. I.e. when a user registers an account, they may ...
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1answer
60 views

Relationship between HTTPS and SSH Public Keys

I can use my private key to generate a public key for use with ssh. I can use the same private key to generate a CSR, to generate a CLIENT certificate for HTTPS. Specifically, my SSH public key is: ...
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37 views

Is it worth it to use sshguard when only allowing ssh login from specific IP?

I'm running a VPS (under ArchLinux) and was wondering if sshguard was useful in the following case. My iptables rule for SSH in looks like this : iptables -A INPUT -p tcp --source $Trusted --dport ...
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I accidentally published my SSH key passphrase, what to do?

So I mistook input fields and now my SSH key passphrase is visible to the world, and I can't even remove it. Now as far as I understand, this is not an immediate security concern, since the ...
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1answer
70 views

Do I have an SSH password?

I have an Ubuntu server hosted on DigitalOcean, I have been using SSH keys since the very beginning. (You can chose for it to be setup before the server instance has even been created). So I have ...
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131 views

Lots of SSH tries on my log. Is it normal?

I have a Raspberry Pi connected to my home and at day 2 of this month I've opened the port 22 of my router so I could SSH it from anywhere. Today by curiosity, I decided to see the raspberry pi log, ...
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Would the authorities in my college be able to see what websites I accessed through tunneling(SSH)?

I study at a college where most social networking sites are banned(Including this one) and if someone is found using them somehow is heavily fined.I just want to know what all can the network admin ...
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107 views

difference between public key and host key and security of host key

In SSH, what is the difference between host key and public key. Public key I believe that is part of private/public key pair, so, that anything sent by server(encrypted using private) can be ...
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68 views

Security of access to local network via VNC over SSH tunnel

I've just set up a Raspberry Pi 2 with the latest raspbian and installed some services. For remote access I've installed tightvnc server which I set up to only allow connections from localhost. I can ...
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Do GPG and OpenSSH use key stretching on their keypairs?

Both OpenSSH and GPG can generate key pairs which are stored as files in well-known paths inside the user directory. A passphrase is always asked for during the generation process, which is then used ...
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51 views

Choosing a cipher and MAC for an SSH connection

The cipher and mac selection according to this are in some sort of order in a config file. How do the client and server know that they are using the same ones though? Is this information exchanged in ...
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136 views

Is port forwarding inherently unsafe?

I had an argument with a person a few months ago when I proposed we forward port 12xyz to an internal SSH server. The target server was tied down in a manner similar to the one recommended by ...
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non-https winscp website

The whole point of WinSCP is to provide a secure channel between a computer and a server. "Secure" means that there is a possibility of an attacker that can view or modify bytes sent both ways. Let's ...
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94 views

How to deal with SSH keys in insecure environment

I am trying to find out a "safe" solution for the following situation. tl;dr how to keep things secure in an environment that is absolutely not? I work in a company where workstations are not safe ...
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128 views

RSA key generation: gpg vs openssh

When I generate RSA key for ssh (both server-side and client-side): dpkg-reconfigure openssh-server ssh-keygen the key generation is completed instantly. However, when I generate RSA key for gpg, ...
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393 views

SSH Public Key Authentication vs Username/password for API Access

I have a linux device that will be making periodic call to an API server, say everytime the system boots up. Everytime then it should authenticate itself and then do its thing. I can either store the ...
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Is there a risk in opening port 22 for ssh access with a network? [duplicate]

Background We have our own datacenter which houses platform specific environments and each environment is isolated. Eeach environment is also has 3 tiers (Web Servers, Application Servers & ...
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1answer
61 views

How secure is Visual host key, and how is SHA2 converted into that representation?

SHA2 has 256 bits of possibilities. Visual host key seems to have the following upper and lowercase = 26*2 numbers and symbols = 20 Additional symbols = 22 Total 94 characters represented in ...
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656 views

Is it always better to put authorized_keys in one's own .ssh directory rather than in root's .ssh directory? [duplicate]

I connect via ssh to multiple Linux servers during the day from my Mac's Terminal window. On my Mac I have the public and private keys in my .ssh directory. On the Linux servers I always use "sudo ...
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Determining a version of SSH from penetration testing?

I am a software developer -- but not a security specialist. A (legitimate) company that does security scans sent my company a notice that we are running an older version of SSH on our hosting server. ...
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113 views

Share root access without sharing password

I am looking for a way to share admin privileges on some hosts without providing the admin password. From his link, I was thinking of using a primary host from which every user can sudo -u user to ...
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1answer
224 views

Does OpenSSH use export ciphers?

With all of this talk of 'FREAK', no one has mentioned OpenSSH. It implements libraries from OpenSSL (until recently, anyway). Why aren't people talking about this? is there even a way to configure ...
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159 views

End-to-end encryption with a reverse proxy and an application server

Lets say that I have an nginx reverse proxy that proxies the traffic to a Tomcat on the same server. I think the most common way to configure this setup is to enable SSL on nginx and then proxy the ...
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1answer
113 views

Linux/ssh - Forensic question

In a Linux terminal, I made a ssh connection from A to B and I used commands to read some files stored in B. Then I disconnected and I closed the terminal. Is it possible to find on A, informations ...
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72 views

Same RSA key pair for all users

Let's say in my computer running Debian i have an RSA key pair generated by user foo and copied the public key to server_A for allowing key based authentication in ssh for foo. Now my question is can ...
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1answer
50 views

Can a compromised OpenSSHD server be used to upload a malicious payload to a client?

Since I'm fairly unfamiliar with the specific details of the SSH protocol, I was wondering if it was possible for a compromised SSHd server to upload a malicious payload (like a Trojan or some other ...
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2answers
68 views

What are the real-world implications of duplicate SSH fingerprints across many devices?

There was a recent post on the Shodan blog showing that certain SSH fingerprints are common across thousands of devices. For example, this fingerprint is common across over 250,000 devices worldwide: ...
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Realistically, how much added security does having a passphrase on a ssh key have?

Let's assume ssh key brute force is unrealistic. It seems to me your greatest vulnerability would be someone gaining access to a client filesystem. If that's the case then key loggers and a host of ...
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PCI DSS and ssh keys for root

Referring to this PCI DSS 2.0 and ssh keys I want to ask Is this PCI section 8.2 only for individual users or also valid if a user connects via ssh to a root account? I prefer to ssh root@localhost ...
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139 views

Has the security of PuTTY been examined?

I am wondering how PuTTY stacks up against other SSH implementations with respect to scrutiny and security of its SSH2 protocol implementation. PuTTY is probably the most-used SSH client on the ...
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191 views

Is it safe to store a passphrase encrypted SSH key in git?

I have a bunch of servers that need to access somewhat sensitive data (passwords for ftps, api keys, etc). Currently I copy a plaintext file back-and-forth between the servers via ssh and encrypt all ...