Some facts about ASA and aaa

default user on ASA has privilege 2
min privilege to have access to ASDM is 2
read-only access to ASDM requires an user with priv 2, service-type ‘nas-prompt’ and ‘aaa authorization command LOCAL’ + access to 'show' commands (Configuration>Device Management>Users/AAA>AAA Access>Authorization and 'Set ASDM Definied User Roles')
telnet on ASA is not allowed on interface with security level = 0
to control which commands are allowed you have to configure:

aaa authentication telnet console LOCAL 
aaa authorization command LOCAL 

privilege show level 7 command crypto
enable password test7 level 7

btw the command “privilege show level 7 command crypto
” is converted to:

privilege show level 7 mode exec command crypto
privilege show level 7 mode configure command crypto

you can exclude host from aaa: aaa mac-exempt match MAC-ACL
using local aaa you can limit the number of failed authentications: aaa local authentication attempts max-fail 2
you can limit the number of proxy connections: aaa proxy-limit 2
proxy - you can define any port for ASA interface without creating a virtual telnet server: aaa authentication listener http inside port 1234

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