Questions tagged [ssh]

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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How do I store other people's ssh keys securely?

This is not really a programming question, but please hear me out. I am building a deployment tool, So using my application others can deploy their own application to their own servers. (just like ...
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34 views

SSH_login not prompting meterprepter?

So Basically I am trying to create a SSH session in metasploit. session opens successfully when I do sessions #, it prints [*] Starting interaction with 4... but when I do a dir, no result or no ...
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92 views

Is the SSH last login message reliable or rather something easy to get tampered with?

My client's Linux server recently got compromised by unknown means (highly likely because of a weak password). When I first logged into the compromised server I discovered the following: The Log ...
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59 views

What are the security implications of connecting to Tor through an SSH SOCKS proxy?

Suppose I have a user account on a remote server run by a friend. I create a SOCKS tunnel on my computer that forwards connections from a local port to the remote server: ssh -N -D 12345 john@10.1.1....
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44 views

SSH Timed out problem [closed]

I can't connect to my kali linux ssh server running in Virtualbox through puTTY. I didn't make any changes to /etc/ssh/sshd_config file, besides Port and PermitRootLogin That's how i booted up my ssh ...
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113 views

What SSH keys should I generate with ssh-keygen to be safe in a quantum computer based world?

What SSH keys should I generate with ssh-keygen to be safe in a quantum computer based world?
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105 views

Malware spreading through jump server and SSH data transfer

Can someone explain to me how jump servers mitigate the risk of malware infection please? Whilst I understand some of the benefits of having a jump server as an extra layer of defence i.e. ...
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1answer
50 views

Is ssh and public key scheme like ed25519 as safe as the hackability of your computer?

I am just learning Linux and I have setup ssh to connect to a server. To do that I need to generate the key for the ed25519 public-key scheme. Once generated, both the public key and the private key ...
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1answer
118 views

Did ZTE put a backdoor in my router? How can I remove it?

I have a ZTE router model ZXHN H198A. Recently, upon connecting to it with Telnet (with some default username-password, of course), I decided to go around the filesystem. Then I noticed that they ...
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2answers
80 views

What is the difference between host and client ssh key generation?

Having read the ssh-keygen man page, i saw the '-h' flag and the following: ssh-keygen supports two types of certificates: user and host. User certificates authenticate users to servers, whereas ...
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1answer
73 views

Using different host key algorithms on sftp server and client

I need to setup a sftp client the problem i am facing is that sftp client library i am using does not support the host key algorithm supported by sftp server. Basically I am talking about the public ...
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1k views

Is SSH secure against MiTM if server fingerprint is not checked, public key authentication is used and confidentiality is not needed for that service?

When connecting to a server for the first time, ssh usually requires users to check server's fingerprint and then caches the info. This is needed in order to prevent MiTM. Is it a design flaw in SSH ...
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69 views

Are there security advantages to adding an OTP to SSH connections?

Are there any tangible improvements to gain from enabling TOTP (google-authenticator PAM plugin) over existing public key based SSH connections? Does it make security sense to enable TOTP based Two-...
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112 views

How safe are passwords while using prompt?

Simple question. How safe are passwords while using prompt? For example logging through SSH. ssh user@server and then you have question for password - of course hidden but... what's going "under ...
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1answer
92 views

Force “Remote Host Identification Has Changed ” warning

I have a client-server pair and am trying to reproduce the warning: REMOTE HOST IDENTIFICATION HAS CHANGED! I am aware that one way to achieve this is to change the ecdsa key on the ssh server and ...
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1answer
191 views

Am I actually seeing a Man-in-the-Middle when pushing to GitHub?

When I attempt git push origin, I get the following error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@...
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3k views

How to pass hash as password to ssh server

I have a hashed password $6$salt$hash. I want to ssh to a linux server with this hash. How could I do that? Do I need to change cipher spec? Is that possible?
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63 views

Public key encryption confusion

I'm learning Linux, and currently SSH. But there are details that I don't really understand. I've seen and understood how Diffie-Hellman key exchanges work from a mathematical point of view, but what ...
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1answer
56 views

What's the difference between SSH tunneling and login into the same SSH server and executing commands?

Consider these 2 scenarios. (1) Let's say I login into an SSH server named A normally using ssh [username] @ [IP address of A]. And now I connected to another server named B which is accepting ...
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56 views

Import ssh keys into gpg (openpgp) as mutliple authentication subkeys?

I have successfully converted ssh keys to gpg primary keys and then converted them to authentication subkeys using pem2openpgp. Unfortunately there is only one primary key and only one authentication ...
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1answer
76 views

Can a SSH jump host act as MITM?

Let's say, for example, a company has a "centralised" SSH bastion/jump host on an untrusted server (e.g. a virtual machine in "the cloud"). Meanwhile the corporate/customer/whatever network(s) have ...
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1answer
215 views

How do I get back to a Meterpreter shell after backgrounding it?

Curious if any of you have an answer to this Metasploit question. It's an issue of a Metasploit session within another Metasploit session. In this lab I'm doing, I need to compromise a machine (10.10....
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3answers
155 views

Is it safe if SSH and HTTPS server share the same RSA/DSA keys?

I'm configuring an ssh server for an embedded device. This device already has an x.509 certificate and a pair of public key and private keys stored in it that is used for its HTTPS server. Is it safe ...
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321 views

Are the sha1 hashes used by common ssh configurations insecure?

I got an automated PCI security test result that checked various server configurations. The automated test determined the server to be unsafe due to the use of sha1 algorithm in some elements of the ...
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3answers
307 views

Is PuttyGen secure?

I'm using PuttyGen to generate ssh keys for various windows computers. It requires a lot of manual user input, specifically in the form of swirling the mouse around in the window pane. I understand ...
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1answer
70 views

Is there any harm to writing a short plain-text string to authorized_keys?

I have a CFN template where I'm seeding an authorized key for testing via paramaters, through a build server. If this value is not provided by the build job, it defaults to a short, plain text string, ...
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102 views

Why does Cain and Abel downgrade SSH version 2 to v 1.51?

I am developing a lab exercise with Cain and Abel and want to know why it is necessary to downgrade SSH before attacking. Identification phase The server sends to the client an identification ...
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I think my ssh server is under attack and it's really trecherous [duplicate]

I'm new here so please bear with me. And thanks for the opportunity. This is an awesome resource. For the past few days, my ssh server (it's a small convenience I run just so that I can access my ...
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1answer
96 views

Should I treat my SSH username like a secret?

I'm trying to automate the deployment of my blog. Most CI providers are using virtual machines/Docker containers with Linux, so I'm learning about shell scripts and SSH now, which is all new to me. ...
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1answer
54 views

Providing access to Git repo behind a Firewall using Certs/Keys for Authentication

We have a Git repo sitting behind a firewall. As I see it, there are two ways of authenticating/accessing the Git repo: Add a Reverse HTTP Proxy in the DMZ that communicates with the Git repo. This ...
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1answer
66 views

Please may I know why I am getting this Sshd log

why I am getting this sshd log Feb 1 13:07:57 sshd[6453]: Failed password for root from 193.34.22.63 port 28980 ssh2 Feb 1 13:08:26 sshd[6897]: Failed password for root from 91.205.189.15 port 48155 ...
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2answers
103 views

Prey vs SSH for remote wipe of stolen laptop under Ubuntu

I have to be able to wipe a stolen laptop remotely (contractual obligation), and the only product I found that supports that on Ubuntu is Prey Project. (Also appears in some other stack exchange ...
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102 views

Sending Private Keys, does it make sense?

There's some logic that I'm not following whenever my organization sets up VMs for SSH access. Perhaps someone can help me understand. Our process is currently as follows Generate Keypair on Linux ...
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3answers
9k views

Does a fake SSH server have any purpose security-wise?

I stumbled upon this sshesame software which appears to imitate an SSH server accepting any username/password, only instead of executing the subsequent shell commands it logs them in a file. What I ...
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1answer
57 views

SIEM: Correlating remote logons to associate origin and target user

How is it possible to correlate or detect user logons eg via ssh/rdp to associate the origin user and target user. My use case is to know who actually (personal/identifiable) used a technical account ...
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1answer
45 views

Is it safe to browse the web through an SSH SOCKS5 connection to an untrusted proxy?

I have established an SSH tunnel to an untrusted machine: ssh -N -D 12345 john@example.com Next, I set up Firefox's connection settings to use the SSH tunnel by setting the SOCKS host to 127.0.0.1, ...
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1answer
86 views

How do these attackers find my IP? [duplicate]

Recently, I have been reading a lot of my ubuntu log files (in /var/log/auth.log), and I can see that some IP addresses are actually trying to 'brute-force' their ways into my VM using SSH by testing ...
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141 views

Use GPG smartcard and gpg-agent to protect multiple SSH keys

I have a Yubikey acting as a GPG smartcard. SSH is configured to use the smart card socket for authentication, and authenticating with the GPG key with Authentication capabilities work fine. ssh-add -...
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113 views

SSH-1 key length

What is the maximum size in bits of one SSH-1 key? 4096? I found some docs where this value is listed and others without limit
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133 views

Techniques used by highly sophisticated entities to snoop on VPN or SSH traffic?

It is mentioned in almost every where that very strong agencies, and governments are able to watch the online activity of the people. Aside from techniques like attacking computer networks, and ...
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1answer
188 views

Risk involved with using SSH for CTF challenges? [duplicate]

I'm new to the INFOSEC scene and was intrigued by the concept of CTF challenges. I was hoping to get started with OverTheWire.org which requires you to SSH to their server to complete the challenges. ...
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1answer
82 views

Why can I use 2 different private keys to connect to my SSH server storing only 1 public key?

On my server ~/.ssh/authorized_keys contains only 1 public key. However, I can connect to it using 2 different private keys. One private key looks like this: -----BEGIN RSA PRIVATE KEY----- ...
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2answers
7k views

How can SSH server know private key is incorrect if passphrase havent been provided yet?

I have server which I am accessing via SSH. I only allow the authentication to be made with private key. Normally when I login via PuTTY, I am first asked for username and then asked for passphrase ...
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1answer
169 views

How do I determine if an existing SSH private key is secure?

For an ordinary user, how would I verify that a private key file was generated using reasonably secure algorithms? In response to things like allegedly insecure ssh-keygen defaults.
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1answer
633 views

What are the best ciphers in terms of performance for SSH tunnel?

From a security standpoint, there are few good cipher options to use with SSH, such as ChaCha20, AES 128/256 GCM/CTR. As I understand (please correct me if I wrong), all of these offer pretty strong ...
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3answers
4k views

Is ssh with public key authentication, no passwords secure enough?

I have a web server set up and would like to connect to it from outside using Tor. The web server simply serves up a simple webpage that will act as an interface for a program running on the machine. ...
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5answers
786 views

Difference between SSH Tunnel / Proxy and VPN in terms of security

What benefits does a VPN have over just using a regular SSH Tunnel? I'm considering setting up OpenVPN on a server, but was wondering what benefits that would have over just using that same server as ...
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1answer
160 views

If my private key is password protected, then how is it used without asking me for it?

Relating to TLS and SSH. If my private key is password / passphrase protected, how is this then used automatically during TLS or SSH communication without asking me for the password?
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Using the same private key for both WSL-Ansible and Putty (or WSL-OpenSSH for that matter)

I use Windows 10 home on my PC and SSHing to up to 5 Linux IaaS machines with either Debian/ArchLinux as server environments. I use Ansible to orchestrate and continuously integrate and continuously ...
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1answer
57 views

How does the public key get authenticated during an ssh session

When using SSH, my private key is stored on my computer safely and my public key is given to the other party I wish to communicate with. I understand that the two keys are mathematically related, and ...