If i setup a meterpreter reverse_https payload and send to multiple targets and they execute the payload whithout my handler running, when I setup the handler will they connect or do I have to have the handler always running for the targets to connect?
After the introduction of transport resiliency in the meterpreter stagers, it will attempt to connect to the handler every 10 seconds (by default) in order to establish a connection with the handler. You can control this through the
SessionRetryTimeout setting at the time of generating the stager. This behavior will be repeated till the current time is less than the
SessionRetryTotal setting. By default it is 1 hour.
So in short, if listener is not available when the stager is executed at the targets, in the default state it will attempt to connect to the handler every 10 seconds for a period of 1 hour.
Further details are available in the Meterpreter Timeout Control wiki.