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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 secure is this instant-messaging setup?

People who want to chat SSH into a private server one of them owns, the owner does a screen -S s1, and everyone connects to this using screen -x s1. They can then chat easily (simple aliases like ...
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14 views

How to check if a SSH Private Key has a passphrase programmitically with C# on Windows 10 [migrated]

I already know there are a couple of similar questions but there is a pattern in the replies that the answers assume that this check is being done on a Linux or similar system. This means they refer ...
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50 views

SSH protocol details [duplicate]

Scenario: I am a developer pushing from a local Git repository upstream using an SSH key, with multiple SSH keys in my keyring. Question: When are my SSH keys used? My current, possibly incorrect ...
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1answer
853 views

How did a bug like CVE-2018-10933 (libssh authentication bypass) happen?

How did a bug like the recent libssh vulnerability come to exist? Exactly what is the nature and root cause of the bug? From libssh's website: libssh versions 0.6 and above have an authentication ...
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Understanding Linux audit.logs for SSH - USER_AUTH [migrated]

Let's say I have this entry in my Linux audit.log: type=USER_AUTH msg=audit(1357702397.903:2747564): user pid=15121 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:authentication acct="test" exe="/...
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3answers
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CVE-2018-10933 - Bypass SSH Authentication - libssh vulnerability

Looks like CVE-2018-10933 was just released today and you can find a summary here from libssh here Summary: libssh versions 0.6 and above have an authentication bypass vulnerability in the server ...
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1answer
56 views

SSH over VPN blocked on certain networks

Why can I only access protected resources over VPN on some networks? Location | SSH to GitHub | SSH to private IP ------------------|---------------|------------------- On-campus Wi-Fi | ...
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1answer
85 views

Honeypot SSH connection attempts with no interaction

I am seeing a lot (>50% of total events) of connection events on a honeypot I have set up but there is no further interaction, no brute force, just a connect then disconnect. I'm thinking this is ...
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1answer
70 views

Why are SQL servers not attacked as frequently as ssh servers?

I have a server running with both SSH and MySQL accessible to the public internet. Both run on default ports (22 and 3306). The ssh server is attacked by bots all the time. This is the output of ...
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0answers
49 views

Could a running SSH server somehow fool connected SSH client to create a reverse port forward?

Let's be extra paranoid and assume that the SSH server my client is connected to, was "enhanced" so that every SSH client that establishes an connection with it, will be tricked into thinking that it ...
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2answers
122 views

End to end encryption in mobile banking? [closed]

Can we use E2EE to secure the communication between the bank and it's customers in the applications of mobile banking? And what is the status off E2EE vs SSH regarding this matter?
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1answer
140 views

Sending shutdown command via ssh using sudo non-interactively

With iOS 12 and the new Siri Shortcuts app, I've been thinking of ways I could leverage the SSH command capability in the app. For those of you who don't know, the app allows you to send a bash file ...
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2answers
120 views

Should I have an SSH bastion?

I am using AWS. I need to connect with a local SSH client to Linux EC2/ECS instances. I also need to connect with a local PostgreSQL client to RDS instances. There are tutorials for creating SSH ...
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1answer
121 views

VPN vs SSH tunnelling for hotel wifi

I know it's recommended to use a VPN with a hotel WiFi but if I'm in a hurry and don't have time to setup my own VPN server would an SSH tunnel (invoked with ssh -D) work just as well to secure my web ...
1
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1answer
67 views

Access from external network safely to raspberry

I am implementing a home alarm system with raspberry and I need to access it from the external network. The initial idea was to use cascade VPN and ssh (in my university to connect to the cluster I ...
2
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1answer
66 views

Can an old SSH session be reconstructed given root access to the server?

Say that A is behind a firewall that logs all packets, communicating with B over a publickey-authenticated SSH connection: A <-------- {ssh} --------> B v v [...
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2answers
4k views

Is telnet secure through SSH tunneling

Firstly sorry, maybe dumb question, but I have one service running on my server which can be operated only by telnet (port 23), but I know that telnet is insecure, so I blocked port 23 in iptables ...
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3answers
141 views

Is there any risk from attempting ssh authentication to a rogue server?

Suppose I'm about to connect to a new (unauthenticated to me) server. I've previously provided my ssh public key to the server owner (who populates it in the appropriate authorized_keys file). The ...
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1answer
41 views

How does Amazon Web Services generate SSH Keys?

How does Amazon Web Services generate SSH Keys? Does it generate the key pair completely in the browser or does it generate the keys in the server and send us the private key over HTTPS? I tried to ...
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3answers
138 views

SSH into router [closed]

Is it possible to gain access to a router by SSHing into it. I understand that you can ssh into a specific server or machine with SSH, but can you do the same thing with a router if you know the ...
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0answers
35 views

What's the easiest way to benchmark the decryption of my “new format” openssh private key?

Ssh-keygen now supports a new key encryption format with -o, and configurable rounds of key stretching with -a. So I want to pick a -a that takes a chosen amount of time on my system. But I don't ...
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2answers
88 views

Does using TLS, SSH and SSL in a connection makes it more secure?

If I use TLS as the protocol to send SSL encrypted packages through a SSH tunnel would this connection be safer than using any of the tools alone? ** EDIT ** Suppose I would TLS(SSL(SSH(data))) (...
2
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1answer
61 views

Is the same key used for Authorization and Encryption? (SSH Tunnel)

I am a bit confused on how SSH encryption works. From reading this question, I see you can use a private key to authenticate with the -i flag. I also know think that SSH encrypts data using ...
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0answers
84 views

Multiple sshd sessions for single SSH login

I was grepping through /var/log/auth.log and noticed that for some reason, not every time, but sometimes when I would log in via SSH I would see entries like the following - where there were multiple ...
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2answers
42 views

Automatic push on commit (on bitbucket repository)

I have a website which commits to a git local repository all the changes done. I need to automatically push them directly from the web server to a remote Bitbucket repository. The authentication ...
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2answers
164 views

how to check if my server has been hacked [closed]

I have a couple of Ubuntu 16.04 servers. I want my server to be secure and ensure they can only be accessible by me and things. I check the auth.log and last. But I heard that hackers can change the ...
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0answers
53 views

yubikey creating different ssh public key having same GPG

I have 2 yubikeys and both are having the same GPG master key besides 3 subkeys for encrypting, signing and authentication, I can encrypt/decrypt and everything regarding gpg seems to be working fine, ...
2
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2answers
113 views

Is running an SSH tunnel from my Web App Server to my Database server safe security-wise?

I have a web app hosted in Digital Ocean and use Laravel Forge to keep a daemon running an SSH tunnel to another server (i.e. ssh -L XXX:127.0.0.1:XXX -p XXXX root@[ipaddress]). I do this in order to ...
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2answers
209 views

From FTP to SSH

Currently, I am doing a penetration testing laboratory with a server with the following services: Nmap scan report for 10.0.11.125 Host is up (1.3s latency). Not shown: 998 closed ports PORT STATE ...
2
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1answer
303 views

Crack Putty Private Key (PPK)

I found a private key which seems to be in the putty private key format. The key has the following header: ---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ---- Subject: <sensitive> Comment: <...
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0answers
120 views

What is an internet-facing system?

I have a home server with access to the Internet. It runs a TeamSpeak server service. On my router, ports 30033 and 10011 are forwarded to the server to allow TeamSpeak to properly run from the ...
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2answers
129 views

Is SSH security necessary on an internal network?

I am running a VM on a spare laptop we have in the office, and have set it up for SSH access from my workstation. Currently I am using user/password authentication, but I would like to remove the ...
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1answer
65 views

Is it ok to delete SSH configuration files? [closed]

From what I read, SSH is mainly used for remotely accessing a machine. If I don't want anyone remotely accessing my machine, nor myself included, is it ok to delete these configuration files from my ...
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28 views

Automatic write from web server to git production repository using passwordless SSH key: is it secure?

I have a WordPress website which has 4 different environments: Development Preview Staging Production These all are connected to 4 remote Git repositories: development, preview, staging and ...
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2answers
33 views

Ansible in a cloud image

I am looking into using Ansible to manage my systems and going through its documentation I found a recommendation to run the Ansible commands on a cloud image rather than my local laptop. My ...
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10answers
17k views

Does it improve security to use obscure port numbers?

I recently started a job at a small company where the CTO prefers to host SSH services at obscure, high numbered ports on our servers rather than the well known port 22. His rationale is that "it ...
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2answers
98 views

Does git use the ssh user keys or the repository's deploy keys for encryption?

In this question I asked, why the SSH-Host key shown when connecting to a gitlab repository does not match the one shown on the instance configuration page. Nevertheless, the accepted answer says that ...
2
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1answer
299 views

Tunnel ssh over http with custom headers

I'm trying to set up corkscrew to make an SSH tunnel over HTTP, but I need to add custom headers after the "CONNECT" statement and before the ssh tunnel. Does corkscrew support it? If yes, how can I ...
2
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1answer
143 views

How to obfuscate SSH tunnel Mac?

I am looking to test a DPI (deep packet inspector). I currently have it set up to block SSH connections (which it does successfully). I have learned that DPI can be bypassed by obfuscating/encrypting ...
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2answers
88 views

Is something like fail2ban necessary for a rate-limited key-only (no password) ssh login?

As far as I understand, bruteforcing ssh is only attempted for passwords, not keys (barring edge cases where presumably the NSA wants to break in). So if a server has disabled (in addition to root ...
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0answers
39 views

Risks associated with long-running SSH connection?

My workflow involves running Jupyter Notebook on a server, and editing & runnig code from my laptop by connecting using ssh -L to that server. Recently, I made this systemd unit that maintains an ...
1
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1answer
295 views

Is my employer decrypting “secure” traffic?

Recently as we started contributing to a project hosted on GitHub we observed that there are problems with connecting securely: $ ssh -T git@github.com Connection closed by 192.30.253.112 port 22 ...
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2answers
86 views

Why is the public key used on server side for an ssh connection?

It is not clear to me why the SSH key authentication needs the public key saved on server. Usually the steps involved are: Generate a key pair on client The public key is saved on server and the ...
2
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1answer
387 views

Use netcat to Pivot

So I have a shell into machine A which doesn't have ssh installed and I can't get a tty shell on (I've tried all of the tty cheat sheets, I think this is intentional) Through machine A I can see ...
3
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2answers
323 views

What is this SSH attack, am I hacked?

I see this in my Ubuntu server's log file: in my ssh my user is root but i see other user Disconnected like "teamspeak", what does that mean? auth.log Jul 3 21:39:01 vmi189193 CRON[25937]: ...
2
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1answer
120 views

SSH Outbound. Tracking down the process

I was pulled up by my ISP in work for having a machine making dozens of outbound SSH connections. I tracked down the machine and took it off the network. Problem is there are several other machines ...
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1answer
43 views

How to assess damage on compromised SSH server on personal computer

Due to a stupid oversight on my side, I have opened my personal computer running Linux to the public internet for a little over 48 hours. Unfortunately, I realized my mistake too late and found ...
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1answer
98 views

Cowrie as a decoy on production server: is it a good idea?

I'm considering setting up a SSH honeypot listening on port 22 on my production servers. I'm hoping that not getting an immediate Connection refused would slow down potential attackers. Are there any ...
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3answers
315 views

SSH to localhost before remote desktop

I currently have Xubuntu 18.04 with Remmina and for some reason, their SSH option doesn't work for me. So I'm left with insecurely accessing my remote machine over the Internet. So I ssh'd to my ...
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2answers
114 views

Is ssh secure if I dont port forward?

If I have a Raspberry Pi, and I install noobs on it. If i connect it to my router and log in with the default user pi over ssh to create another user to then delete the pi user, is it secure? Since ...