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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Generate RSA2 key in OpenSSH format in windows

I have to generate a key, RSA v2 in OpenSSH format. I am a bit confused. I am trying to generate it using Putty key generator. There I see an option SSH2-RSA and SSH1-RSA. So is SSH2-RSA the RSA2 key ...
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190 views

“Fix” man in the middle

I've just tried to ssh connect to a server (auth via ssh key), and get the well-known message WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!. I'm the server administrator (but I'm not really a good ...
6
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1answer
139 views

Does a VPN provide any security benefits over sshuttle or a vanilla ssh tunnel?

I use sshuttle to tunnel my traffic through one of my remote boxes whenever I'm in a cafe or connected to an insecure network. Does a VPN provide any additional security benefit over this kind of ...
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1answer
61 views

How Google has an SSL certificate from itself and my browser doesn't give an error [duplicate]

I know that I can create my own SSL certificate, but in this case the browser will give 'not trusted' error to the user, as the certificate is not browser trustworthy. So companies go and get an SSL ...
3
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1answer
526 views

Decrypt SSH traffic in pcap file given private key

I have a Pcap file that contains some SSH encrypted packets. I have the server public and private key. How do I decrypt these private keys? Is it possible to get the session key using Wireshark or ...
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Does changing /etc/ssh/moduli impact previously generated keys?

My company does a lot of automated file transfers over SSH/sftp with banks, etc. A recent SSH upgrade on a server dropped support for the old/weak diffie-helman-group1-sha1 key exchange protocol in ...
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5answers
2k views

How does a network admin block the reverse SSH in company?

Given firewall inbound: all are blocked outbound: allow port 80, 443 Problem colleagues are still able to ssh to home device by port 80/443, and establish a reverse ssh tunnel from company to ...
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1answer
122 views

How are man-in-the-middle attacks actually implemented? [closed]

For research purposes. I'm wondering, in a high level way, how MITM attacks are actually done in the real world. So over the internet the client talks to the server, or one person emails the other, ...
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5answers
177 views

Should I generate new SSH private keys for each machine I work from?

I hope this is an appropriate place to ask this question. I've been thinking recently about public and private keys, and I'm wondering what the best practices are related to management of my own ...
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2answers
67 views

Isn't ssh-copy-id exposing to a brute force attack?

It is a common knowledge, that using keys to authenticate ssh users is more secure than using passwords. However, even with password login disabled, when running ssh-copy-id I am still asked for ...
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1answer
64 views

Are there any risks associated with SSH agent forwarding?

I just realized that I need SSH agent forwarding in order to push to one Git server that then forwards the commits to Github.com. I never used SSH agent forwarding and don't understand the security ...
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1answer
59 views

How does one typically monitor their privileged admins encrypted SSH & RDP sessions?

From a compliance (& perhaps just for pure due-diligence) standpoint, what do IT departments typically deploy to keep an eye on their privileged administrator's remote access sessions? Also ...
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Secure protocol for a backup server? [closed]

I want to make a back up system in my home, but I don't know I should use a FTP server or a TPC-based cloud server or a SSH-based server. Which method is best in security? I just want to upload and ...
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2answers
72 views

How is the server authenticated in ssh? [duplicate]

The server does not know any secrets that can be used to authenticate itself. Also, what good is a fingerprint if it is based on the public key if it is basically the hash of some known public key. ...
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1answer
80 views

System breach or OpenSSH glitch?

The system runs a SSH daemon, and a nginx web server, both ports being open to the internet. We are part of a university so our ports are forwarded from the main router to the intranet. At about ...
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2answers
42 views

ssh/scp from server to server — set permissions (no root)

I have access as a regular user (not as root) to two servers. Server A is accessible via ssh with a username and password, Server B can only be accessed using a keycard and pin. I need to set up a ...
5
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1answer
113 views

Is a ddos attack that makes ssh auth attempts a possible way for attackers to significantly impact your system?

I'm noticing on my digital ocean server, that I'm getting a high volume of auth attempts. I don't have any passwords since I use sshe key auth, so I'm not worried about a break in. But can a ...
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1answer
66 views

SSH MITM on new host

If you are connecting to a new host for the first time, what is to stop an intruder from performing a MITM attack: swap out the public key and fingerprint for a public key they have the private key to ...
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Programmatically open router ports via port triggering

I'm getting many brute force attacks on my home computer which is behind a DSL modem (very old D-Link, has only web interface), so I decided to protect SSH this way: Every time I want an SSH ...
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2answers
167 views

Is it possible to acquire an SSH authorized RSA private key just by having access to the server?

Is it possible to get hold of an RSA private key (pem file) simply by having (root) access to a server that authorizes ssh access using that that private key. For example, can the entries in ...
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2answers
277 views

Does CVE-2015-5352 work if there is no active X-Server?

My security program shows that one of my servers is vulnerable to CVE-2015-5352. If X-Server is not running (not even installed) is the system really penetrable by that vulnerability?
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611 views

download file/folder anonymously on a ssh session

I rent a paid VPS hosted online and want to transform it to a sort of treasure chest where I can upload and download files privately. For this purpose I want to do this operation over the Tor network. ...
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191 views

DSA, ECDSA and RSA [duplicate]

Conventional wisdom these days is that in the context of SSH keys, DSA is insecure and RSA is preferred (or that they are both fine, but RSA is more secure, depending on who you ask). As I understand ...
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2answers
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SSH cache secrets

Why does SSH use public key crypto each time you connect to the server? RSA/DSA are computationally expensive, so why can't they just be used the first time to share a secret, and then in the future ...
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SSH-Keygen Fingerprint providing Letters and Numbers Result [closed]

I've been using SSH and public key crypto for a few months. I've run into a new problem with my install of the newest public beta of OS X, and can't find an answer online. When I run SSH-Keygen -lf ...
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1answer
112 views

How should I tunnel arbitrary protocol traffic over HTTPS?

I'm posting this question from a moving train! (Ok, maybe that's not so impressive.) This train has an annoying WiFi - it's low-throughput, high-latency, tends to lose packets, and blocks most kinds ...
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3answers
204 views

Managing SSH key access to AWS servers behind bastion

I currently have an AWS setup with 3 VPCs, one for the bastion, then a Dev and a Prod VPC, those last two only being SSH accessible via the bastion of course (layout from this great guide). I'm ...
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5answers
103 views

Best practice to guard against an app copying private ssh keys stored under ~/.ssh?

Given that any application running as the logged in user will have read access to that user's ~/.ssh folder, it seems trivial for the application to copy that user's private key and send it over the ...
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6answers
324 views

Can people know the server I'm connecting to despite being on SSH/HTTPS? [duplicate]

I understand that by connecting securely over SSH or HTTPS, the data that I transfer is cryptographically secure. However, can someone spying on my connection still determine the server I'm sending it ...
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2answers
65 views

Managing passwordless SSH authentication from servers to server

I have a bunch of servers that need to transmit data to one server using SCP. What is the best practice for using SSH key-based authentication? Option 1: Create a unique private key for each host and ...
2
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1answer
150 views

PPP over SSH - is this correct?

I see a lot of talk online about whipping up a VPN connection using PPP over SSH. This term confuses me, as SSH is an app tier protocol and PPP operates on the data-link layer. So, my question is: ...
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1answer
75 views

Repeated security questions after remote key has changed

I reinstalled one of my machines and gave it new ssh keys, which should yield warnings when I connect to it from a machine I have connected from earlier. First I get the big warning that the remote ...
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1answer
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Protecting SSH service with many inexperienced users

One of the universities I know has a rather unique password policy. They issue shell accounts to all computing students with strong passwords that are unchangeable. It is done via the passwd -n flag ...
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My friend revealed both private and public keys for his server. How serious is this?

A friend of mine managed to expose both id_rsa and id_rsa.pub file from his server via apache. I mentioned to him that this is serious security issue but he brushed this off like it was no big deal. ...
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1answer
147 views

Private VPN server in public cloud

I need to encrypt all my traffic, because I often work in unsecure network environments. My questions is this: if I buy my server from VPS providers (amazon ec2, digitalocean, etc) - how secure ...
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3answers
241 views

Does SSH password authentication provide the server with the password?

If an attacker takes control of a server and a user tries to SSH into it using password authentication, can the attacker get the password? I was under the impression that there was an algorithm in ...
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3answers
375 views

How secure is socks5 proxy over ssh?

At work we are all using Windows 7+, with full administrative privileges. Each PC has a dedicated IP and a proxy is used. It is set as a HTTP proxy and the option to use this for all types of ...
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0answers
183 views

Adding a binary to the firmware of a routing device [closed]

I've been playing around with a router d-link dwr-921 and found some vulnerabilities in the web interface. I still haven't managed to get shell access and now I'm thinking about modifying the firmware ...
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63 views

Detect SSH InBound / Oubound Connections

I'm noodling with the idea of managing SSH connections on Linux server using a program (not sure what it will be written in yet) that monitors inbound and outbound connections. Is there a way to ...
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1answer
129 views

Is it possible for an SSH MITM to attack only if the key isn't in the known_hosts?

I was trying to connect a server using a different port when the network seemed too slow. It gives an ECDSA key, while the previous key in the known_hosts is RSA. I refused to continue the connection ...
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1answer
640 views

Is it possible having only public key from SSH keypair to see if private key is password protected?

As a person responsible for security I wonder on this subject. To provide best security I don't want to accept/deploy public keys for users if private key is not password protected. However there ...
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3answers
916 views

SFTP on Windows - is it likely to be disabled?

I'm a software engineer and I'm maintaining a product that allows a user to run commands and scripts on Linux servers via an SSH connection. We now need to extend this functionality onto Windows. We ...
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213 views

Public/private key auth and VPN

If a server uses public/private key authentication to access SSH, will there be any advantage of restricting the access of SSH over VPN? This link describes both approaches to solve brute force ...
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821 views

Can an attacker “simulate” a private IP address?

I have a SSH server with a rule that does not allow password connections outside the local network. So people already on the local network, either physically or via VPN, are allowed to connect with ...
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2answers
81 views

Security of nested ssh

First of all, by nested ssh, I mean the following way of using ssh: ssh usera@Bob 'ssh usera@C' suppose A wants to login on server C, but for some reason C is not directly available to A (e.g. C's ...
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2answers
128 views

Can you use ssh for secure inter app communication on the same device?

I use ssh to get an encrypted connection between servers and local machines all the time. It's fast, it's secure, and there's a way to do it in nearly every system programming language that I've used ...
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166 views

Are OpenSSH vs OpenSSL public key format names mismatched?

I generated a key pair vis OpenSSH and later wanted to generate PEM encoded public key. I noticed that generated public key differs when generated by OpenSSH vs OpenSSL when using same format name ...
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1answer
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Will two virtual machines running on the same physical host machine get the same value from /dev/random?

Will two virtual machines running on the same physical host machine get the same value from /dev/random if read over the same time period? Say that Virtual-machine-1 wants to generate its ssh host ...
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1answer
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Why does the server ssh public key not look like the key in client known hosts?

From my naive understanding of ssh, the server shares its public key ( /etc/shh/ssh_host_rsa_key.pub ) with the client, who then adds it to the list of known hosts ( /user/.ssh/known_hosts ). So, I ...
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Server compromised with magento vulnerability, possible rootkit

I am experiencing a security issue with one server that it happens that I manage. I will try to cite all relevant facts as briefly as possible. I am asking for any additional information and course of ...