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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Hack scenario when a person has a non-superuser shell [closed]

Suppose that there are following three machines in the network: Machine A: Microsoft Server 2003 Service Pack 2 FileZilla 0.9.29 beta ftp server (TCP 21) Mcafee ePolicy server (81), remote desktop ...
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In the Diffie-Hellman key exchange, how is the shared base key 'p' known and how are A and B, protected from Eve?

I'm trying to wrap my head around Hellman, Diffie, and Merkle's key exchange design, but after reading the Wiki article about it, I can't figure out how the commonly known factor ('p', I think) comes ...
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3answers
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How to create ssh tunnel using netcat?

I want to create reverse connection between two machines, but these is a firewall in the middle preventing all connections, except ssh. I want to create ssh tunnel using netcat, could you please tell ...
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Encryption-Laws in Iran

According to this article Iran has criminalized the usage of encryption and VPNs. According to this blog post it is still possible to use SSH tunnels in Iran. For me SSH is encryption and thus ...
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ssh public/private key pair

I am having problems understanding how ssh really works. I know it uses a public key cryptography to encrypt messages. However, I can ssh to a server without first generating a public/private key pair ...
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How do I get SSH to prompt me with the RSA key instead of the ECDSA key?

I am trying to SSH into my fresh Ubuntu 12.04 server. At the client I have deleted known_hosts. SSH to the host for the first time has it offering me an ECDSA key to verify. The problem is I know ...
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5answers
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Confusion: Why isn't a passhrase encrypted SSH key two factor auth?

I'm trying to figure out the best practices for accessing my devbox from a public terminal. Most sources I've found recommend protecting the box with some kind of two factor authentication, such as ...
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4answers
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Can public keys be a security risk when performing password-less SSH logins?

Some companies use monitoring software such as nagios or icinga. In order to perform checks on the servers, they often need password-less SSH logins. The servers being checked put the public key of ...
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Do these mysql and ssh issues mean my rails server was hacked?

I'm running a rails application on an ubuntu server on slicehost. I got a pingdom alert that the server was unreachable, so I tried to load the website in my browser. It showed a Passenger error, ...
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Is using a public-key for logging in to SSH any better than saving a password?

Using a public/private key pair is fairly convenient for logging in to frequented hosts, but if I'm using a key pair with no password, is that any safer (or less safe) than a password? The security ...
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Is there an easy way to see a log of SCP activity on a server (ala /var/log/secure for ssh login)?

On Linux systems, /var/log/secure (or similar, depending on distro) shows all SSH login activity. Is there a similar log for SCP? If not, what's a good approach to enabling logging of scp activity ...
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SSH : Remote Host Identification Changed

As part of my daily routine, I was SSH'ing to one of the corporate servers. However this time I was presented with following message @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ ...
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How often should an SSH key pair be changed? [duplicate]

Possible Duplicate: How often should an SSH key pair be changed? I've been using a passphrase-protected 1024-bit RSA key for passwordless SSH via ssh-agent between my own systems for years. ...
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Security Concerns with X11 Forwarding

What are some of the security concerns and reasons either for or against allowing X11 Forwarding. I have generally taken an approach of not allowing it under the blanket guise of security. Recently, ...
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4answers
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What's the safest way to access my US-based bank's website from within Mexico? VPN vs SSH vs HTTPS?

I will soon be moving to Mexico and living there for an extended period. During that time I will need to occasionally access my US-based bank's website. I'll always be connecting using my own laptop, ...
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1answer
220 views

What would the high priority steps be for securing a small (cloud) application?

No doubt there is much good information at this link on hardening a linux server and at the child links off of that. And at this link to relevant tools it seems there has not yet been a popular ...
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1answer
58 views

File directory deletion [closed]

So I heard this guy talkin about how one time he deleted someone's windows directory remotely. He claimed to have gotten into the system and deleted it such that the files are all still there, but the ...
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1answer
452 views

Protection against a fired IT employee [duplicate]

Possible Duplicate: When a sysadmin leaves what extra precautions need to be taken? We have some servers on two sites. We use Puppet to allow only SSH key (root denied) and authorize users ...
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Why can an encrypted private key be brute forced?

When using SSH keys to authenticate to a server for remote access, why is it possible to devise the true key and therefore the passphrase from an encrypted private key, without checking each guess of ...
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3answers
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Can ssh keyfile security be broken in a few hours if the file is exposed?

At this link there is a claim that if an RSA key has a strong passphrase security might be broken in a few hours if an attacker has the private key. Is there something weak about the security of RSA ...
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174 views

Smartphone SSH clients with shared user

I am writing an application for smartphones to provide very limited SSH usage. The user cannot perform arbitrary actions when logged in. They can run a specific script(s) only. For various reasons ...
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2answers
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Does TLS-OBC only improve security of Web Browsers? Does it improve the security of SSH?

I'm studying the TLS-OBC extension and would like to know if it improves security of non Web-based protocols? Specifically, would it be of any benefit to SSH clients? (version 1 or version 2.x/secsh) ...
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3answers
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Is there a compelling reason to ssh tunnel RDP connections?

We don't run any Microsoft products natively in our office, but there are a few folks who use a linux RDP client to access an application on remote virtual desktops with a service provider. Would it ...
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2answers
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Is IP spoofing relevant to TCP? Is it relevant for TLS or SSH?

I have read the TCP Connection Establishment on Wikipedia In brief the packets to start are SYN, with a (hopefully) random sequence number A from the client. SYN-ACK, responding, with A+1 and ...
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2answers
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Is it less secure to use OpenDNS for banking accounts, SSH, Adsense account?

I have one WiFi connection in my house which I use for my iPad, phone and computers. I want to block adult sites, time consuming sites for every device that use the WiFi connection. So I came across ...
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4answers
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can ssh passwordless public key authentication be ok if combined with a VPN?

Having a debate with a coworker about the merits & faults of public key authentication with ssh. I'm basically wondering what all the possible merits and faults are, especially in regards to ...
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3answers
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Is it OK to use the same password for a Linux login and the SSH private key?

I want to remotely log in to my Linux server with SSH. Public/private key authentication is more secure than password authentication, so I have disabled password-based authentication for SSH on my ...
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1answer
980 views

Security issues related to public keys and SSH

Do I have to mind something specific when using public keys and SSH? Well of course, I have to keep my private key secret (and therefore I should choose a strong pass phrase). But is there something ...
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3answers
874 views

Public wifi security protocols

I should apologise first- this post could seem a lot to ask for, but I am starting to go around in circles. I am interested in securing my laptop for when I use public wireless hotspots, as I am a ...
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4answers
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Reusing Private/Public Keys

I have accounts on several third party sites - Bitbucket, Bluehost, etc. From what I've gathered, it is common practice to use one key pair for all [id_rsa, id_rsa.pub], but only to give out the ...
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3answers
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How to use VNC with SSH tunnel - “is this howto secure”?

PC-A: the local machine, from where i want to see the remote machine [Fedora] PC-B: the remote machine, where the vnc server will be [Ubuntu] install a vnc client [from where you want to connect] on ...
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2answers
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SSH Tunnelling: How can I stop users being able to access services bound to localhost via port forwarding?

I want to be able to offer ssh accounts on my linux server for people to be able to use for SSH tunnelling. All accounts will be locked down with no interactive shell, for tunnelling / port forwarding ...
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3answers
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How can I convert my encypted PGP secret key for use performing SSH authentication?

I wish to covert my PGP key (RSA) to be used performing SSH authentication. After some searching, I found openpgp2ssh, which appears to be an appropriate tool. Everything works swimmingly for my ...
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2answers
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Sudo password when authenticating via passwordless SSH

I've got a few boxes all networked together on Amazon EC2, each of which are in automated communication with each other via SSH (rsync, etc). As such, I've created SSH keys on each of these machines ...
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2answers
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What are the security implications of SSH tunneling?

We have an internal lan (not connected to internet, all internal ip addresses, behind a firewall, no routing to outside), we also have a machine that sits on the edge of our lan (two nics, one on the ...
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1answer
240 views

What is the security implications of enabling SSH onward connections

I was reading SSH tips and tricks from http://blogs.perl.org/users/smylers/2011/08/ssh-productivity-tips.html There is a section on Onward Connections and the author warns not to use this unless you ...
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Is there a reason to disable root login, if SSH connections are restricted to a single IPv4 address?

I have a linux server running centos, and while hardending the SSH server, I asked myself: Is there a reason to disable root login, when only I (assuming my IP address is static, and i have direct ...
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1answer
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How is tunnelling SSH through Poxytunnel/HTTPS different from doing it through SSL with Stunnel?

In an answer to What is the difference between SSL, TLS, and HTTPS, it's said that HTTPS is HTTP over SSL/TLS. That is, an SSL/TLS connection is established first, and then normal HTTP data is ...
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Creating tunnel with most ports closed?

How can I create a proxy tunnel from a network that has all ports but port 80 closed? I guess I'd have to bind SSH on my server to port 80, but would that introduce problems to my home network since ...
6
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2answers
527 views

How can I authenticate a client connection in a secure way?

Let's say I have a server listening on port 1234. I have some client software that needs to be able to connect to this port. But I want to prevent malicious users from bypassing the client software ...
4
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2answers
804 views

Which is the easiest secure file transport protocol to implement (SFTP, FTPS, HTTPS, FTP over SSH, FTP over IPsec)

I have to select a secure file transfer protocol, to be implemented in a pre-boot system. I have access to libraries with the basic network functionalities (IP, TCP, UDP, etc...). I might also have ...
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Risks of ssh to an untrusted host?

I use ssh a lot to connect to a variety of servers at my university. The machines are administrated by students, so assume they can't really be trusted;-) What are the risks in making a ssh ...
6
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3answers
289 views

How do I securely exchange server logins with remote developers?

I work for a virtual organization (we're all remote) that uses a lot of freelancers/subcontractors. Very often I need to exchange SSH login information with developers working on projects for us. How ...
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3answers
438 views

Is it insecure to have an SSH server on a workstation?

I know one systems administrator who runs SSH Server on his workstation to push files to it and check things from a phone but I think it is a bad idea for several reasons: An operations workstation ...
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4answers
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software to keep a list of IP that try to access ssh over a set of rules and feasibility

i'm interested in software or set of scripts to keep a lists of filtered IP that attempt to brute-force ssh, and to label an IP as brute-forcing i would add some checks like: one attempt to log as ...
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1answer
149 views

Security track record of SSHD on Windows machines?

How do the various SSH daemons that run on Windows compare in terms of security? Vulnerabilities found, reviews by respected reviewers, source code availability, etc. I only need access to a cmd ...
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1answer
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SSH Brute Force Dictionaries

Request for logs please. So, I had an interesting question posed to me around geographical trends in SSH brute force attempts. The question being "has anybody ever looked into the prevalent SSH ...
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1answer
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Is SOCKS secure?

In order to create a VPN, I open an SSH tunnel with a command like ssh -D 9000 user@host, and then I set my system's proxy settings to use SOCKS5 through localhost:9000. Well, setting up my home ...