SSH not working after security enhancement

[david.krupicka]

Hi,
our customer uses SecureCRT v7.2 and asks us to enable DES encryption, which is unsecure. Is it really the case?
We have these ciphers enabled
Ciphers aes256-ctr,aes192-ctr,aes128-ctr

Are they supported in v7.2? If so, what needs to be done?
Unfortunately I can't test v7.2, because I have no license.

Best regards
David

[bgagnon]

Hi David,

I am not sure of the context of the inquiry.

Are you the admin of an SSH server that the customer using SecureCRT 7.2 is connecting to?

If so, yes, SecureCRT has supported the CTR ciphers since version 6.1.x. If not enabled, the CTR ciphers can be enabled in the Connection / SSH2 / Advanced category of SecureCRT's Session Options.

[david.krupicka]

Hi Brenda, thanks for the answer.

Yes, I am the admin of the server.
The issue is resolved already, the problem laid in KexAlgorithms.
Unfortunately, the customer did not provide any logs or traces.

Nevertheless, I allowed only diffie-hellman-group-exchange-sha256,
we resolved the issue by adding diffie-hellman-group14-sha1, which should be still ok nowadays.

Best regards
David

[bgagnon]

Hi David,

Thanks for the update.

Support for diffie-hellman-group-exchange-sha256 key exchange method was added in v7.3.x. Your customer can check their upgrade eligibility here.