RSA modulus too small: 512 < minimum 768 bits

$ ssh [email protected]

ssh_rsa_verify: RSA modulus too small: 512 < minimum 768 bits

key_verify failed for server_host_key

fgvm-ha1 # config system global

fgvm-ha1 (global) # set admin-ssh

admin-ssh-grace-time    Maximum time in seconds permitted between making an SSH connection to the FortiGate unit and authenticating (10 - 3600 sec (1 hour), default 120).

admin-ssh-password      Enable/disable password authentication for SSH admin access.

admin-ssh-port          Administrative access port for SSH. (1 - 65535, default = 22).

admin-ssh-v1            Enable/disable SSH v1 compatibility.

fgvm-ha1 (global) # set admin-ssh-v1 enable

fgvm-ha1 (global) # end

fgvm-ha1 # show system global

config system global

    set admin-ssh-v1 enable

    set alias "fgvm-ha1"

    set hostname "fgvm-ha1"

    set language simch

    set timezone 55

end
 

vyos@ispout-vyos:~$ ssh -v -1 -c des [email protected]

OpenSSH_5.5p1 Debian-6+squeeze5, OpenSSL 1.0.2l  25 May 2017

debug1: Reading configuration data /etc/ssh/ssh_config

debug1: Applying options for *

debug1: Connecting to 192.168.50.46 [192.168.50.46] port 22.

debug1: Connection established.

debug1: identity file /home/vyos/.ssh/identity type -1

debug1: identity file /home/vyos/.ssh/identity-cert type -1

debug1: Remote protocol version 1.99, remote software version K8FnH

debug1: no match: K8FnH

debug1: Local version string SSH-1.5-OpenSSH_5.5p1 Debian-6+squeeze5

debug1: Waiting for server public key.

debug1: Received server public key (1152 bits) and host key (1024 bits).

debug1: Host '192.168.50.46' is known and matches the RSA1 host key.

debug1: Found key in /home/vyos/.ssh/known_hosts:4

debug1: Encryption type: des

debug1: Sent encrypted session key.

Warning: use of DES is strongly discouraged due to cryptographic weaknesses

debug1: Installing crc compensation attack detector.

debug1: Received encrypted confirmation.

debug1: Doing challenge response authentication.

debug1: No challenge.

debug1: Doing password authentication.

[email protected]'s password:

debug1: Requesting pty.

debug1: Requesting shell.

debug1: Entering interactive session.

debug1: fd 0 clearing O_NONBLOCK

fgvm-ha1 #

fgvm-ha1 # show system global

config system global

    set admin-ssh-v1 enable

    set alias "fgvm-ha1"

    set hostname "fgvm-ha1"

    set language simch

    set timezone 55

end

fgvm-ha1 # 

============ End