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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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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2answers
4k views

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 ...
6
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4answers
1k views

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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3answers
523 views

Monitoring and filtering of arbitrary outgoing data

I would like to be able to not just centrally monitor but also filter any organizational data moving out our edge routers, regardless of the sender application and regardless of the protocol/port used ...
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1answer
221 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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4answers
10k views

Secure use of psexec or better alternative to it

I want to remotely start VMWare virtual machines (I own VMWare Workstation) and to this end I need to execute on host something like "vmrun -T ws H:\VMWare\VM1\VM1.vmx nogui" with user desktop ...
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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 ...
5
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1answer
456 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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3answers
1k views

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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2answers
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Taxonomy of Ciphers/MACs/Kex available in SSH?

SSH offers a large variety of algorithms for Ciphers, MACs and KexAlgorithms configuration options. Sometimes I need quick and light (my own internal network), and sometimes I want all the ...
4
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2answers
313 views

Recently set up a server, Need security help

I set up a server running debian I opened port 22 allowing access to ssh into the port. I keep getting weird messages in my router log saying: [LAN access from remote] from 211.161.46.101:57201 to ...
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2answers
2k views

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
122 views

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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9answers
3k views

Can IP address be a component of 2-factor authentication?

I have a bunch of Linux machines that I wish to administer over the Internet. I currently use SSH keys, but have been advised to use 2-factor authentication. SSH Keys are something you know. Is an IP ...
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3answers
176 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
1k views

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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5answers
2k views

Encryption laws in India — is it allowed to use ssh and VPN?

I have a very similar question to the one asked here (regarding Iran). However, I would like to use ssh and vpn while being in India. I found already this survey of cryptographic laws but I don't ...
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4answers
1k views

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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1answer
5k views

Dropbear SSH server use-after-free vulnerability

"This vulnerability is located within the Dropbear daemon and occurs due to the way the server manages channels concurrency. A specially crafted request can trigger a use after free condition which ...
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3answers
515 views

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 ...
8
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5answers
2k views

Which is the most vulnerable to MITM attacks, SSL or SSH?

Which is the most vulnerable to MITM attacks, SSL or SSH? Here's the scenario, you have 20 minutes to set up a web proxy like this: Laptop -> Chrome Browser -> Web Proxy -> Internet You must secure ...
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3answers
838 views

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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4answers
2k views

What's the common pragmatic strategy for managing key pairs?

I have a small number of different workstations (plus client devices like iPhone) that I use for to connecting to numerous servers using SSH. Originally when I learned about PKI, I created a single ...
4
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1answer
6k views

Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I ...
4
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1answer
1k 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
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ECDSA Keys Changed, SSH insecure now?

I'm running some non-critical Ubuntu servers in my dorm room in college. Turned them off before break, come back, SSH in, and get a warning that the ECDSA keys have changed. It looked pretty much ...
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11answers
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What alternatives are there when SSH is being actively filtered?

Unfortunately our government filters the SSH protocol so now we can't connect to our Linux server. They do the filtering by checking the header of each packet in the network layer (and not by just ...
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4answers
4k views

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 ...
9
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3answers
890 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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7answers
7k views

Are passwordless SSH logins more secure?

I had a long discussion with my co-workers whether key-based SSH authentication (particularly for OpenSSH) is more secure than authentication using passwords. My co-workers always connect to servers ...
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2answers
787 views

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
4k views

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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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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2answers
1k views

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 ...
13
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2answers
14k views

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 ...
3
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1answer
242 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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5answers
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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
1k views

Consequences of compromised /etc/ssh/moduli

Hypothetically, what could an attacker achieve if they have a copy of of /etc/ssh/moduli?
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1answer
4k views

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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2answers
1k views

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 ...
4
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2answers
817 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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3answers
1k views

What is the difference between encrypted data and data sent through an encrypted tunnel

I am looking at different VPN protocols. [1] L2TP does not provide encryption so require IPSec to encrypt the data [2] IPSec tunnel provide encryption to the tunnel What is the difference in terms ...
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7answers
3k views

What security implications are there for allowing outbound SSH traffic?

My school currently blocks outbound SSH traffic. Users inside the network cannot use Port 22, and attempting to make an SSH connection over another port is also blocked. (I'm assuming the firewall ...
4
votes
3answers
2k views

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 ...
6
votes
3answers
290 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
440 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 ...
240
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7answers
190k views

RSA vs. DSA for SSH authentication keys

When generating SSH authentication keys on a Unix/Linux system with ssh-keygen, you're given the choice of creating a RSA or DSA key pair (using -t type). What is the difference between RSA and DSA ...
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4answers
176 views

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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6answers
6k views

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 ...
3
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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 ...