SSH (Secure shell) is a protocol for secure communication between computers to execute remote commands, transfer data and tunnel TCP connections.

learn more… | top users | synonyms

2
votes
2answers
70 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 ...
1
vote
1answer
125 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 ...
4
votes
1answer
61 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 ...
-1
votes
2answers
53 views

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 ...
1
vote
2answers
79 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. ...
4
votes
1answer
109 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 ...
1
vote
2answers
50 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 ...
4
votes
1answer
234 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 ...
5
votes
1answer
68 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 ...
1
vote
0answers
103 views

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 ...
2
votes
2answers
175 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 ...
3
votes
2answers
369 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?
5
votes
2answers
637 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. ...
0
votes
0answers
192 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 ...
2
votes
2answers
317 views

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 ...
2
votes
1answer
148 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 ...
1
vote
3answers
269 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 ...
2
votes
5answers
110 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 ...
1
vote
6answers
353 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 ...
5
votes
2answers
68 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
votes
1answer
183 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: ...
1
vote
1answer
77 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 ...
4
votes
1answer
115 views

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 ...
43
votes
3answers
9k views

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. ...
2
votes
1answer
173 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 ...
5
votes
3answers
324 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 ...
3
votes
3answers
475 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 ...
1
vote
0answers
238 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 ...
1
vote
2answers
74 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 ...
3
votes
1answer
162 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 ...
6
votes
1answer
644 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 ...
4
votes
3answers
1k 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 ...
1
vote
2answers
287 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 ...
9
votes
3answers
912 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 ...
3
votes
2answers
95 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 ...
3
votes
2answers
145 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 ...
1
vote
1answer
206 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 ...
2
votes
1answer
99 views

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 ...
3
votes
1answer
167 views

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 ...
1
vote
2answers
172 views

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 ...
2
votes
0answers
847 views

Convert RSA openSSH key/putty key to gpg key [closed]

Scenario Two work sites, site 1 and site 2. Two Linux servers, server A and server B. Server A is reachable from both sites, while server B is reachable from site 1 only. Two Windows workstations, ...
2
votes
0answers
171 views

Does enabling VPN on our router increase the risk of our network being exposed to the outside network? [closed]

We are thinking about using VPN to connect our remote office and the main office and also support developers working from home. To do this, we are planning to purchase 2 CISCO (or similar) routers to ...
1
vote
2answers
3k views

Risks of having SSH private key stolen

I'm afraid this is quite a common question, but searching several times through the questions did not prove useful, and I'm really eager of knowledge here :D I understand that keeping SSH private key ...
4
votes
2answers
308 views

Sharing RSA keys between PGP and SSH protocols: Does this pose a security risk?

If I generate a PGP subkey that only has the authentication capablity and use this to generate an SSH keypair to authenticate Git for example, does this pose a security threat? When I do, should I ...
1
vote
1answer
1k views

Metasploit SSH Error: could not settle on kex algorithm

I am running a trial of Cobalt Strike which runs over the Metasploit Framework. I am trying to perform an SSH related attack on my laptop, and I get the error in the title for all SSH related attacks. ...
2
votes
0answers
118 views

chroot ssh users [closed]

I am using CentOS 7. I need to give shell access to ssh users but restrict them in a jail. I have used jailkit to set up the jail. I have copied all necessary libraries, binaries that are needed for ...
5
votes
1answer
3k views

SSH Key: Ed25519 vs RSA

A lot of people recommend using Ed25519 instead of RSA keys for SSH. The introduction page of Ed25519 (http://ed25519.cr.yp.to/) says: [..] breaking it has similar difficulty to breaking [..] RSA ...
3
votes
2answers
383 views

What stops an SSH server from MITMing logins?

When I read this question about what gets signed with the private key by the client I wondered: What stops the following scenario from happening: A client connects to an SSH server. The SSH server ...
2
votes
2answers
6k views

Break in attempts from secureserver.net

Over the last few weeks I have seen dozens if not hundreds of break-in attempts from ip addresses which map back to secureserver.net. I know these are GoDaddy machines from the who is look up. ...
2
votes
1answer
510 views

Are there any security implications in creating an SSH key for the root user?

I've written an install script on a server to quickly set up new sites in the /srv directory. It needs to do a git clone, and has to be run via sudo in order to have the permissions to do all the ...