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Which encryption algorithms does PRTG SSH sensors support



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Upon doing a open-vas security scan on my servers I get the following security risk:


The remote SSH server is configured to allow weak encryption algorithms.

Vulnerability Detection Result

The following weak client-to-server encryption algorithms are supported by the remote service:

  • 3des-cbc
  • aes128-cbc
  • aes192-cbc
  • aes256-cbc
  • arcfour
  • arcfour128
  • arcfour256
  • blowfish-cbc
  • cast128-cbc
  • [email protected]

My sensors are currently in compatibility mode as they give error state in default.

SSH server version:

  • OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013

I found this:

Important note: PRTG includes a new SSH engine as of version 16.2.24 to provide best performance and security for your SSH sensors. Please consider this SSH engine as beta: it still does not support all OpenSSH libraries but we are working on it. If PRTG's new SSH engine does not yet work in your case, you can still use the old SSH engine as legacy version: select the Compatibility Mode for SSH Engine in the sensor or device settings. In this case, please consider the article below.

So back to my question, which encryption algorithms do the sensors support. Please specify for both default & compatibility mode so I can allow only the algorithms

compatibility disk-free meminfo openssh prtg

Created on Jan 27, 2017 12:49:54 PM by  arielvz (0) 1

Last change on Jan 23, 2018 1:45:24 PM by  Luciano Lingnau [Paessler]

1 Reply



Your Vote:



Sorry for the delayed reply. Default mode supports:

Machmac-sha2-512,hmac-sha2-256, hmac-sha1,none
Kex[email protected],ecdh-sha2-nistp256,diffie-hellman-group1-sha1,diffie-hellman-group14-sha1
Host Keysssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521, ssh-dss,ssh-rsa

Compatibility mode is only listed for reference, since it's already deprecated and will be removed sooner or later:

Cipheraes192-cbc, aes256-cbc
Kexdiffie-hellman-group1-sha1, diffie-hellman-group14-sha1
Host Keysssh-rsa, ssh-dss

Created on Feb 2, 2017 12:16:14 PM by  Stephan Linke [Paessler Support]

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Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.