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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2answers
56 views
any reason not to run tmux/wemux on a bastion host?
Is there any reason to worry about running tmux/wemux on a bastion host? It seems to me that it would open up vectors to have your terminal sessions hijacked by some locally exploited account on the ...
0
votes
1answer
41 views
Does ssh-keyscan tell you if a server supports RSA or DSA keys?
A question came up on the Unix & Linux SE site: Checking if passwordless ssh authorization is possible without permission for sshd_config?.
I immediately thought you could possibly infer this ...
1
vote
1answer
56 views
Simple and secure remote installation method that accepts input via a web page?
When installing software on a remote server: Is it possible to let the admin (i.e. the user that installs the software) define admin username and password via a HTML page, in a secure manner?
...
-2
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0answers
48 views
how do i ssh using Proxychains [closed]
I have searched all over net to just findout how to SSH into a system using Proxychains.
Basically I want to SSH into my Linux(mint) machine which is having public IP. Another machine (laptop) is ...
2
votes
1answer
112 views
What is the actual value of disabling remote root login using ssh?
I have read the answers regarding why you should disable remote root login, but there is something nagging me. Assume this:
Scenario 1:
Remote server A.
Remote root login disabled.
Password ...
0
votes
2answers
79 views
Working from many places <-> being able to restrict SSH access to server to IP range
I administer a webserver, and while I'd like to restrict the SSH access to an IP range, I wouldn't be able to do so because a) I travel a lot and b) I don't have a static IP at my homeoffice.
I've ...
2
votes
1answer
52 views
SSH Protocol classification version exchange messages
I am trying to classify network protocols over network traffic . Now my task is SSH protocol. I read the RFC and know SSH starts with protocol exchange message from both client and server .
Format ...
7
votes
1answer
108 views
Using / finding covert channels in inter-process communication
I've got a class exercise that involves a virtual game of Werewolves/Mafia. We're not really taught how to do anything in this class, which makes it hard for everyone to do the labs.
The idea is that ...
1
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1answer
131 views
Vulnerability by leaving an open port in a pc
I have the following set-up.
Home pc ---reverse ssh tunnel---> to linux server
The reverse ssh tunnel is set-up so that on my home pc, port 22 is open, but I have nothing currently listening on that ...
4
votes
4answers
310 views
What are the ways to implement two factor authentication?
We have devices that can generate tokens. So we can use tokens with passwords to perform two factor authentication. There are many ways to implement such systems to enhance security. One of two I ...
3
votes
1answer
200 views
Two-factor authentication with ssh key authentication and yubikey?
OpenSSH won't invoke PAM at all if public key (RSA)
authentication is configured and the client presents a valid key.
So if you use key-based auth, you can't enforce 2FA easily.
One workaround for ...
5
votes
2answers
137 views
Linux forensics questions (ssh config, user activity)
I'm a linux noob and have an assignment I'm a bit stumped on... We're given VirtualBox (vdi) images and raw files for the state of a linux server at 3 different dates.
We're supposed to answer:
...
4
votes
2answers
133 views
SSH password vs. key authentication
I've usually been told that public key authentication is strongly preferred over password authentication for SSH. However our previous admin was against public keys and only issued passwords and took ...
3
votes
3answers
195 views
Using /usr/bin/passwd as login shell
I have a requirement to set up a SSH tunnel between two hosts. SSH server runs on a Linux host, and the SSH client (PuTTY) runs on a Windows host.
I have set up a separate user account (say 'tunnel') ...
0
votes
3answers
206 views
Brute forcing ssh keys
My problem is a common one: I deleted my SSH key, and forgot to set rm to point to a .trash file. I have the public key, and I need to get in this server. I am not doing this on anyone else's server. ...
1
vote
1answer
91 views
Custom Python Server - how to secure it?
I'm going to purchase my own dedicated server service soon and run few python server scripts on it.
Firstly, let me tell you that I am total noob when it comes to internet security and was unable to ...
2
votes
2answers
260 views
Converting keys between openssl and openssh
If I use the following
openssl req -x509 -days 365 -newkey rsa:2048 -keyout private.pem -out public.pem -nodes
I get private.pem and public.pem
If I use
ssh-keygen -t rsa -f rsa
I get rsa and ...
4
votes
1answer
56 views
GPG warns about unprotected subkeys while using monkeysphere
Issuing monkeysphere subkey-to-shh-agent GPG warns me:
gpg: about to export an unprotected subkey
then it asks for the passphrase and everything works fine.
What's the meaning of "export an ...
23
votes
4answers
1k views
Should I change the default SSH port on linux servers?
Is there any advantage in changing the SSH port, I've seen people do that, but I can't seem to find the reason why.
If you have a strong password and/or a certificate, is it useful for anything?
...
1
vote
1answer
151 views
What is the difference between RSA1 & RSA in regards to SSH? Also when is the fingerprint & random art used?
I have searched this site for RSA1 with no results. From multiple google searches I have understood that RSA1 was used in SSH1 (which isn't recommended). However if its a single algorithm why are ...
6
votes
1answer
240 views
Is it secure to transfer an RSA public key by email?
I've set up my VPS'ssh server to accept only key-based identification: I disabled password-based connection.
As a consequence I am connecting from home with an RSA key generated prior to password ...
0
votes
3answers
111 views
Make the public key unrecoverable given the private key
OpenSSL seems to bundle the private key together with the public key when it produces .pem files. Is there a way to prevent this from happening; i.e. prevent OpenSSL from creating a .pem private key ...
1
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4answers
242 views
Our logs showing a lot of SSH brute force attacks originating on Port 11
this forum has been brilliant so far. Just wondering if I can get a bit more help:
Can I get some info on a large amount of SSH brute force attacks originating from port 11 on the external host over ...
4
votes
1answer
297 views
How to set up OpenSSH to use x509 PKI for authentication?
I do not mean simply putting the public RSA key of a x.509 certificate into ~/.ssh/authorized_keys - I'm looking for a way to set up a ssh such that x.509 certificates signed by a pre-defined CA will ...
2
votes
2answers
168 views
How to secure a truecrypt container allowing access with multiple SSH public keys?
I would like to create a TrueCrypt container which can be accessed by multiple people. The container itself can be stored anywhere, e.g. in a shared folder in Dropbox or Google Drive, ...
I would ...
3
votes
2answers
143 views
What are the differences between ssh generated keys(ssh-keygen) and OpenSSL keys (PEM)and what is more secure for ssh remote login?
I have learned there are 2 methods to make SSH remote login easier and secure , those are;
ssh generated keys (using ssh-keygen)OpenSSH Keys
PEM (.pem) keys usually generated with OpenSSL (Amazon ...
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vote
2answers
256 views
Is SSH2 still vulnerable to man-in-middle attacks?
With SSH using RSA public key authentication, can an attacker spoof the server IP address and connect with client to obtain client password?
0
votes
0answers
68 views
I need help configuring OpenSSH on Win2008 via CYGWIN [closed]
I need help configuring OpenSSH on Win2008 via CYGWIN!
THANKS in advance!
I am trying to configure an OpenSSH server on Windows Server 2008 Datacenter via CYGWIN. I have installed and configured ...
1
vote
1answer
554 views
SSH Bad Protocol Version Identification String- What is it?
I need some help identifying some Bad Protocol version identification errors from our server.
I've Googled the strings but not found much about it. We're getting the following:
sshd[xxxx]: Bad ...
1
vote
4answers
300 views
SSH: reusing public keys and known-man-in-the-middle
Usually, people recommend to use a single private-public key pair everywhere (if we're not talking about a possibility of compromising the private key):
Best Practice: “One per-user ssh key” or ...
12
votes
4answers
669 views
Attract Brute Force SSH Attacks
I posted a question on Server Fault, but got downvoted and had the question closed.
One of the comments suggested looking over here, so here goes:
For my senior project, I'm working on an ...
1
vote
2answers
307 views
how safe is a home NAS with ssh access?
I'm thinking about acquiring a NAS from Synology (or QNap), these are pretty cool NAS and do much more than just storing files.
Some extras include:
ssh, ftp, telnet, mail servers
photo gallery ...
2
votes
3answers
127 views
How to regain access to the server?
I have a Debian server with KVM available 24/7. It was recently broken into and its root password changed.
My hosting provider has restored my access and helped me change the password. But in the ...
3
votes
2answers
385 views
Disabling authentication via DSA keys in OpenSSH?
How can I disable DSA and ECDSA authentication on my server with OpenSSH 5.9? Sifting through the documentation material and doing a web search didn't yield any results - only an old bug report for ...
4
votes
1answer
491 views
What are the differences between the arcfour, arcfour128 and arcfour256 ciphers in OpenSSH?
What are the differences between the arcfour, arcfour128 and arcfour256 ciphers in OpenSSH?
I am interested about: speed and security implications.
I know that arcfour is fast for file transfers, ...
1
vote
1answer
112 views
Implementing Secure Remote Password with Remote Desktop Application
I had read the Secure Remote Password Protocol paper written by Tom Wu. This protocol is resistant to dictionary attacks. I have also go through some papers regarding to VNC attacks due to weak ...
2
votes
2answers
131 views
Attacks in SSL and SSH
I have a question
Assume that we have two end-host A and B connected by two routers R1 and R2. A wants to send a large file to B.
1) A decides to establish ssh connection with host B using public ...
2
votes
2answers
143 views
Why CAs instead of global fingerprint database?
Why do we use "too big to fail" CAs and the chain of trust instead of a global fingerprint database in a similar vein to how ssh works?
6
votes
3answers
297 views
Can I develop SSH-based tools within United States?
It is well known that development of open-source cryptographic tools is very problematic within the United States: all open-source ssh-based software was specifically developed outside of the US of A ...
2
votes
2answers
646 views
OpenSSH default/preferred ciphers, hash, etc for SSH2
When using OpenSSH server (sshd) and client (ssh), what are all of the default / program preferred ciphers, hash, etc. (security related) and their default options (such as key length)?
So, what are ...
11
votes
2answers
466 views
Which SSH security is stronger? 2 Factor or Public key
For SSH authentication, which is more secure?
2 Factor Authentication using a USB token/Google Authenticator(time based)
OR
Public/private key with password
Or could they be both used at the same ...
3
votes
2answers
153 views
length of ciphers versus length of key
ssh-keygen defaults to RSA (for SSH protocol 2) and a 2048 bit key.
At this description of ssh
The supported ciphers
are: 3des-cbc, aes128-cbc, aes192-cbc, aes256-cbc, aes128-ctr,
...
2
votes
4answers
157 views
I think my server is under attack, what can I do to stop it? [duplicate]
Possible Duplicate:
Invalid users trying to log in to my server
I have a small ssh server mostly used for file sharing. A couple of other people and I use it and there are only 3 users. ...
8
votes
2answers
254 views
Vulnerabilities of Secure Shells
I ssh into my school's engineering computer to submit large programmin projects on a regular basis. Are there any vulnerabilities or worries about using this channel so frequently? What makes a secure ...
3
votes
1answer
190 views
What are some steps to take for securing a Linux server that aren't in this list of obvious ones?
Obvious things:
Disable root login (rather, don't enable it)
Secure SSH (no root login, key auth only, timeout after inactivity, whitelist users who can SSH in, etc.)
IP Tables firewall whitelisting ...
0
votes
1answer
104 views
SSH Log: “Accepted password for user…”
I have only port 29999 open for SSH connections. But in the log file I see entries like this:
Accepted password for user1 from 190.101.200.100 port 55805 ssh2
saying that a connection was accepted ...
0
votes
2answers
117 views
Improve SSH logs
I want to improve my SSH log. I would like to basically be able to see failed attempts with ip address and the password used. is that possible?
Right now I see something like this:
Failed password ...
0
votes
3answers
244 views
Petraeus scandal - what would have been a better way to communicate electronically [closed]
Not a security professional here but .... having read through how it happened, it's clear sending these emails from the shared account by Paula Broadwell was the problem (if I understand correctly). ...
2
votes
1answer
295 views
How to restrict SSH access outside of LAN? [closed]
We have several dedicated servers.
We need to ensure "root" user can not be accessible through SSH outside of LAN.
I have searched and found the followings #
...
3
votes
1answer
169 views
Replacing weak SSH fingerprint algorithms
Even though MD5 has been broken for years and its vulnerabilities have been used to create real-world rogue X.509 CAs and other horrible things, OpenSSH and PuTTY still use MD5 as the default public ...
