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WMI Defense

三好学生 · 2015/09/07 10:20

0x00 前言

前两篇分别介绍了WMI Attacks & WMI Backdoor，侧重于攻击，所以这篇介绍一下WMI Defense，攻防结合，便于大家更清楚认识WMI.

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0x01 简介

本篇侧重于介绍如何通过Powershell调用WMI监视自身系统、记录入侵行为，并对WMI的检测工具做具体测试。

0x02 测试环境

Win8 x86 powershell v3（win8默认安装）开启Winmgmt服务，支持WMI

0x03 监视系统

*注：以下均为Powershell代码

1、监视进程创建

 $filterName = 'BotFilter48'
    $consumerName = 'BotConsumer48'

    #查询进程创建事件

    $Query = "SELECT * FROM __InstanceCreationEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process'"

    $WMIEventFilter = Set-WmiInstance -Class __EventFilter -NameSpace "root\subscription" -Arguments @{Name=$filterName;EventNameSpace="root\cimv2";QueryLanguage="WQL";Query=$Query} -ErrorAction Stop

    #写入日志文件

    $Arg =@{
                Name=$consumerName
                    Filename = 'C:\test\log.log'
                    Text = 'New Process Created with name %TargetInstance.Name%'
                }

    $WMIEventConsumer = Set-WmiInstance -Class LogFileEventConsumer -Namespace "root\subscription" -Arguments $Arg

    Set-WmiInstance -Class __FilterToConsumerBinding -Namespace "root\subscription" -Arguments @{Filter=$WMIEventFilter;Consumer=$WMIEventConsumer}

如图

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2、监视进程结束

$filterName = 'BotFilter49'
$consumerName = 'BotConsumer49'


# 查询进程结束事件

$Query = "SELECT * FROM __InstanceDeletionEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process'"
$WMIEventFilter = Set-WmiInstance -Class __EventFilter -NameSpace "root\subscription" -Arguments @{Name=$filterName;EventNameSpace="root\cimv2";QueryLanguage="WQL";Query=$Query} -ErrorAction Stop

$Arg =@{
                Name=$consumerName
                Filename = 'C:\test\log.log'
                Text = 'Task kill with name %TargetInstance.Name%'
    }
$WMIEventConsumer = Set-WmiInstance -Class LogFileEventConsumer -Namespace "root\subscription" -Arguments $Arg

Set-WmiInstance -Class __FilterToConsumerBinding -Namespace "root\subscription" -Arguments @{Filter=$WMIEventFilter;Consumer=$WMIEventConsumer}

如图

enter image description here

3、监视注册表

（1）监视单一键值

$filterName = 'BotFilter51'
$consumerName = 'BotConsumer51'

$Query ="SELECT * FROM RegistryKeyChangeEvent WHERE Hive='HKEY_LOCAL_MACHINE' AND KeyPath='SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run'" 

$WMIEventFilter = Set-WmiInstance -Class __EventFilter -NameSpace "root\subscription" -Arguments @{Name=$filterName;EventNameSpace="root\default";QueryLanguage="WQL";Query=$Query} -ErrorAction Stop

$Arg =@{
                Name=$consumerName
                Filename = 'C:\test\log.log'
                Text ='The change is HKEY_LOCAL_MACHINE\\%KeyPath%'
    }


$WMIEventConsumer = Set-WmiInstance -Class LogFileEventConsumer -Namespace "root\subscription" -Arguments $Arg

Set-WmiInstance -Class __FilterToConsumerBinding -Namespace "root\subscription" -Arguments @{Filter=$WMIEventFilter;Consumer=$WMIEventConsumer}

监视 “HKEY_LOCAL_MACHINE\\SOFTWARE\Microsoft\Windows\CurrentVersion\Run” 键值的任何改动

如图

enter image description here

(2)监视某一键值及其子键

监视 “HKEY_LOCAL_MACHINE\\SOFTWARE\Microsoft” 键值及其子键的任何改动

$filterName = 'BotFilter52'
$consumerName = 'BotConsumer52'

$Query ="SELECT * FROM RegistryTreeChangeEvent WHERE Hive='HKEY_LOCAL_MACHINE' AND RootPath='SOFTWARE\\Microsoft\\'" 

$WMIEventFilter = Set-WmiInstance -Class __EventFilter -NameSpace "root\subscription" -Arguments @{Name=
$filterName;EventNameSpace="root\default";QueryLanguage="WQL";Query=$Query} -ErrorAction Stop

$Arg =@{
                Name=$consumerName
                Filename = 'C:\test\logtree.log'
                Text ='The change is HKEY_LOCAL_MACHINE\\%RootPath%'
    }

$WMIEventConsumer = Set-WmiInstance -Class LogFileEventConsumer -Namespace "root\subscription" -Arguments $Arg
Set-WmiInstance -Class __FilterToConsumerBinding -Namespace "root\subscription" -Arguments @{Filter=

$WMIEventFilter;Consumer=$WMIEventConsumer}

0x04 检测工具测试

测试工具：

Sysinternals Autoruns

检测目标：

能否查出所有WMI定时运行的操作

测试方法：

在目标主机运行包含以下Consumer的定时运行操作，使用Sysinternals Autoruns进行检测。

-ActiveScriptEventConsumer
-CommandLineEventConsumer
-LogFileEventConsumer
-NTEventLogEventConsumer
-ScriptingStandardConsumerSetting
-SMTPEventConsumer

测试结果：

如图

enter image description here

Sysinternals Autoruns只能检测到ActiveScriptEventConsumer和CommandLineEventConsumer的操作，可以理解为上述对进程和注册表监视的操作无法识别

解决措施：

直接查询WMI调用，即可获得所有定时执行的操作

#List Event Filters

Get-WMIObject -Namespace root\Subscription -Class __EventFilter


#List Event Consumers

Get-WMIObject -Namespace root\Subscription -Class __EventConsumer


#List Event Bindings

Get-WMIObject -Namespace root\Subscription -Class __FilterToConsumerBinding

0x05 WMI使用补充

以上三篇关于WMI的文章均采用Powershell实现，当然用mof和vbs也能够实现，这里给出一些参考代码，其他功能代码按照格式修改即可

1、mof文件记录注册表修改的操作

（1）以下文件保存为reg.mof文件

 #pragma namespace ("\\\\.\\root\\subscription")
    instance of __EventFilter as $Filter
    {
        Name = "RunKeyFilter";
        QueryLanguage = "WQL";
        Query = "Select * from RegistryTreeChangeEvent"
                " where (Hive = \"HKEY_LOCAL_MACHINE\" and "
                "KeyPath = \"Software\\\\Microsoft\\\\Windows"
                "\\\\CurrentVersion\\\\Run\")";

        // RegistryTreeChangeEvents only fire
        // in root\default namespace
        EventNamespace = "root\\default";   
    };

    instance of LogFileEventConsumer as $Consumer
    {
        Name= "consumer1";
        Filename = "C:\test\log.log";
        Text ="The change is HKEY_LOCAL_MACHINE\\%KeyPath%";

    };
    // Bind the filter to the consumer
    instance of __FilterToConsumerBinding
    {
        Filter = $Filter;
        Consumer = $Consumer;
    };

（2）编译mof文件

命令行下管理员权限执行mofcomp reg.mof

2、vbs文件记录注册表修改的操作

strComputer = "."
Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\default")
Set colEvents = objWMIService.ExecNotificationQuery _
    ("SELECT * FROM RegistryKeyChangeEvent WHERE Hive='HKEY_LOCAL_MACHINE' AND " & _
        "KeyPath='SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run'") 
Do
    Set objLatestEvent = colEvents.NextEvent
    Wscript.Echo Now & ": The registry has been modified."
Loop