In Juniper ATP Cloud, a threat prevention policy allows you to define how the system should handle an infected host. Two of the available actions are:
Close the connection: This action will close the connection between the infected host and the destination to which it is trying to connect. This will prevent the host from communicating with the destination and will stop any malicious activity.
Quarantine the host: This action will isolate the infected host from the network by placing it in a quarantine VLAN. This will prevent the host from communicating with other devices on the network, which will prevent it from spreading malware or exfiltrating data.
Sending a custom message is used to notify the user and administrator of the action taken. Drop the connection silently is not an action available in Juniper ATP Cloud.
According to the Juniper documentation, the threat prevention policy in Juniper ATP Cloud is a configuration that defines the actions and notifications for different threat levels of the traffic. The threat levels are based on the verdicts returned by Juniper ATP Cloud after analyzing the files, URLs, and domains. The threat levels range from 1 to 10, where 1 is the lowest and 10 is the highest1.
The threat prevention policy allows the user to specify different actions for different threat levels. The actions can be applied to the traffic or to the infected host. The actions available for the traffic are:
Permit: Allows the traffic to pass through the SRX Series device without any interruption.
Block: Blocks the traffic and sends a reset packet to the client and the server.
Drop: Drops the traffic silently without sending any reset packet.
Redirect: Redirects the traffic to a specified URL, such as a warning page or a sinkhole server.
The actions available for the infected host are:
None: Does not take any action on the infected host.
Quarantine: Quarantines the infected host by applying a firewall filter that blocks all outbound traffic from the host, except for the traffic to Juniper ATP Cloud or the specified redirect URL.
Custom: Executes a custom script on the SRX Series device to perform a user-defined action on the infected host, such as sending an email notification or triggering an external system.
Therefore, the two different actions available in a threat prevention policy to deal with an infected host are:
Block: This action will block the traffic from or to the infected host and send a reset packet to the client and the server. This will prevent the infected host from communicating with the malicious server or spreading the malware to other hosts.
Quarantine: This action will quarantine the infected host by blocking all outbound traffic from the host, except for the traffic to Juniper ATP Cloud or the redirect URL. This will isolate the infected host from the network and allow the user to remediate the infection.
The following actions are not available or incorrect:
Send a custom message: This is not an action available in the threat prevention policy. However, the user can use the custom action to execute a script that can send a custom message to the infected host or the administrator.
Drop the connection silently: This is an action available for the traffic, not for the infected host. It will drop the traffic without sending any reset packet, which may not be effective in stopping the infection or notifying the user.
References: 1: Configuring Threat Prevention Policies
