Metasploit中Exploit模块check方法详述

Exploit模块的check方法用来检测一台远程主机是否有漏洞能够被利用。check方法默认的实施仅返回check方法不被Exploit模块支持。当然，一个完整的代码能够从check方法返回如下表所示的信息。

如果在我们编写Exploit模块的时候没有编写check方法，当我们在Msfconsole中输入check时，会调用Msf：：Module中定义好的check方法，并返回Msf::Exploit::CheckCode::Unsupported这个常量。根据Ruby语法，当我们在Exploit模块中再次定义check方法时，便会覆盖继承的check方法，从而我们可以具体情况选择返回值，例如：

def check
	if ***
		return Exploit::CheckCode::Vulnerable
	end
	return Exploit::CheckCode::Safe
end

所有的常量信息在Msf::Exploit::CheckCode模块中定义如下：

Unknown = [ 'unknown', "Cannot reliably check exploitability."]

Can't tell if the target is exploitable or not. This is recommended if the module fails to retrieve enough information from the target machine, such as due to a timeout.

Safe = [ 'safe', "The target is not exploitable." ]

The target is safe and is therefore not exploitable. This is recommended after the check fails to trigger the vulnerability, or even detect the service.

Detected = [ 'detected', "The target service is running, but could not be validated." ]

The target is running the service in question, but the check fails to determine whether the target is vulnerable or not.

Appears = [ 'appears', "The target appears to be vulnerable." ]

The target appears to be vulnerable. This is recommended if the vulnerability is determined based on passive reconnaissance. For example: version, banner grabbing, or having the resource that's known to be vulnerable.

Vulnerable = [ 'vulnerable', "The target is vulnerable." ]

The target is vulnerable. Only used if the check is able to actually take advantage of the bug, and obtain hard evidence. For example: executing a command on the target machine, and retrieve the output.

Unsupported = [ 'unsupported', "This exploit does not support check." ]

The exploit does not support the check method.

常量数组中的第二个元素即为check方法的返回值，例如：