exploit/multi/local/periodic_script_persistence: Unset DefaultTarget

[bcoles]

The exploit/multi/local/periodic_script_persistence module sets an invalid target index within the DefaultTarget option.

metasploit-framework/modules/exploits/multi/local/periodic_script_persistence.rb

Lines 37 to 46 in 55bb277

	'Targets' => [
	[ 'OSX', { 'Arch' => [ARCH_X64, ARCH_X86, ARCH_AARCH64], 'Platform' => 'osx' } ],
	[ 'Python', { 'Arch' => ARCH_PYTHON, 'Platform' => 'python' } ],
	[ 'Unix', { 'Arch' => ARCH_CMD, 'Platform' => 'unix' } ],
	[ 'Bsd', { 'Arch' => [ARCH_X86, ARCH_X64], 'Platform' => 'bsd' }]
	],
	'DefaultOptions' => {
	'DisablePayloadHandler' => true
	},
	'DefaultTarget' => 4,

Targets are zero-indexed. As such, 4 is an invalid target index.

This caused issues with the Local Exploit Suggester (#20609).

I'm not sure why 4 (presumably 3) was chosen as the default target. This target does not perform automatic targeting and is not a safe default target for all platforms.

This PR removes the default DefaultTarget value, forcing the operator to knowingly and intentionally chose a target.

[adfoster-r7]

Release Notes

Fixes a bug in the exploit/multi/local/periodic_script_persistence module which caused issues for the Local Exploit Suggester