Attacker uses application, which traverses all possible or popular words which could be used as a password, as soon as valid password would be found.
Weak passwords are prone to this attack.
Following services are prone to this type of attack:
- SSH console. After password has been guessed attacker could perform whenever actions he wants with the server - perform parallel VoIP proxy attack, add new SIP account and terminate huge amount of calls, steal your confidential data, etc.
- web-interface. After password has been guessed, attacker could add new VoIP account and terminate huge amount of calls or steal your confidential data.
- SIP. In case if you have configured peers with dynamic IP address in SIP parameters, after password has been guessed, could terminate huge amount of calls.
- Fail2Ban application
- Limited SSH access
- Password strength check system
- Balance cutoff
- Origination control
- Encrypted passwords