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
55 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
40 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 ...
23
votes
3answers
14k views
What is the difference between SSL vs SSH? Which is more secure?
What is the difference between SSH and SSL? Which one is more secure, if you can compare them together?
Which has more potential vulnerabilities?
1
vote
1answer
54 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
111 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 ...
7
votes
2answers
6k views
What is the difference between authorized_key and known_host file for SSH?
I am learning basics of SSH protocol. I am confused between the contents of the following 2 files:
~/.ssh/authorized_keys: Holds a list of authorized public keys for servers. When the client ...
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
vote
1answer
130 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
302 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
198 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 ...
4
votes
1answer
55 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 ...
5
votes
2answers
136 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
131 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 ...
5
votes
3answers
388 views
What is the difference between encrypted data and data sent through an encrypted tunnel
I am looking at different VPN protocols.
[1] L2TP does not provide encryption so require IPSec to encrypt the data
[2] IPSec tunnel provide encryption to the tunnel
What is the difference in terms ...
2
votes
2answers
257 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 ...
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
142 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
2answers
1k views
What is the “openssh-blacklist” package? Is it related to the Debian OpenSSL bug?
What is the "openssh-blacklist" package? Is it related to the Debians OpenSSL bug?
6
votes
1answer
239 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 ...
-1
votes
1answer
1k views
Dropbear SSH server use-after-free vulnerability
"This vulnerability is located within the Dropbear daemon and occurs due
to the way the server manages channels concurrency. A specially crafted
request can trigger a use after free condition which ...
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
vote
4answers
299 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 ...
1
vote
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
294 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
167 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
141 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 ...
1
vote
2answers
255 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
549 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 ...
12
votes
4answers
668 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
377 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 ...
5
votes
5answers
959 views
Which is the most vulnerable to MITM attacks, SSL or SSH?
Which is the most vulnerable to MITM attacks, SSL or SSH?
Here's the scenario, you have 20 minutes to set up a web proxy like this:
Laptop -> Chrome Browser -> Web Proxy -> Internet
You must secure ...
1
vote
3answers
219 views
Monitoring and filtering of arbitrary outgoing data
I would like to be able to not just centrally monitor but also filter any organizational data moving out our edge routers, regardless of the sender application and regardless of the protocol/port used ...
4
votes
1answer
485 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, ...
11
votes
2answers
463 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 ...
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
129 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 ...
4
votes
3answers
1k views
Possible to use both private key and password authentication for ssh login?
It seems that they are mutually exclusive, as disabling one gives me the other, and vice versa. Two-factor auth for my ssh servers sounds really nice, so is there any way to accomplish this?
2
votes
2answers
635 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 ...
3
votes
2answers
150 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,
...
