Category: Networking

Use TOR proxy with any linux command

There is an easy way to use the The Onion Router for any command under linux

First install TOR and proxychains4

$ sudo apt install tor proxychains4

You can configure proxychains.conf but the default config is good 🙂

$ sudo nano /etc/proxychains.conf

Then start the tor service

$ sudo systemctl start tor

And check your ip:

$ proxychains4 curl ifconfig.me

You can use any command you want. So if you want your firefox browser over tor:

$ proxychains4 firefox

To refresh your TOR IP simply restart the TOR service

Happy proxying 🙂

Git SFTP

I was working for an elementary website of a friend of mine. I pushed the website to GitHub so it’s was way easier to maintain the site.

But I thought it must be easier than transferring all the changes every time by an FTP program. So I found git-ftp and of course FTPS didn’t work out of the box 😉

Windows

What you have to do to enable GIT FTP (on Windows)

First start an ssh sessions from powershell

ssh [email protected]

This will add the public key to you known host. Otherwise you will get this error later

fatal:  Can't access remote 'sftp://SOMEUSER:***@SOMEHOSTNAME'. Network down? Wrong URL? exiting...

You can see this with the -vv parameter

git ftp init -vv

Now it’s time to install git-ftp

  • First go to c:\program files\git
  • Then run git-bash as administrator

And install git-ftp (bin is an alias for program files)

$ curl https://raw.githubusercontent.com/git-ftp/git-ftp/master/git-ftp > /bin/git-ftp
$ chmod 755 /bin/git-ftp

No go to your project and enter these commands

git config git-ftp.user SOMEUSERNAME
git config git-ftp.url sftp://SOMEHOSTNAME/public/sites/SOMEWEBSITE/
git config git-ftp.password SOMEPASSWORD
git ftp init

And the next time you make a change you only have to do

git ftp push

Linux (Debian)

For linux the steps are much easier.

First start an ssh sessions from bash

ssh [email protected]

This will add the public key to you known host. Otherwise you will a error later.

Now install ftp-git

$ sudo apt install git-ftp

No go to your project and enter these commands

git config git-ftp.user SOMEUSERNAME
git config git-ftp.url sftp://SOMEHOSTNAME/public/sites/SOMEWEBSITE/
git config git-ftp.password SOMEPASSWORD
git ftp init

And the next time you make a change you only have to do

git ftp push

When you get an errors like these:

zo 19 dec 2021 23:11:50 CET: Retrieving last commit from sftp://******:***@s*******/public/sites/*********/.
*   Trying *********:22...
* Connected to ******* (********) port 22 (#0)
* Found host ******** in /home/******/.ssh/known_hosts
* Set "ecdsa-sha2-nistp256" as SSH hostkey type
* Closing connection 0
curl: (79) Error in the SSH layer

zo 19 dec 2021 23:11:50 CET: fatal: Could not get last commit. Use 'git ftp init' for the initial push. Can't access remote 'sftp://******:***@********'. Network down? Wrong URL? exiting..

Then try the --insecure parameter

git ftp push -vv --insecure

Happy uploading 🙂

DHCP Test Tool

I had to check my DHCP configuration for a Dell Wyse Thin Client. But when you configure specific options like 161 and 162 you don’t see that options in a Wireshark capture during a Windows DHCP request.

Luckily for us CyberShadow created a great tool to test some specific DHCP settings an he even make it open source: https://github.com/CyberShadow/dhcptest

This DHCP tool have 2 great features:

  1. You can do a request for specific DHCP option
  2. You can send a vendor class so in my case I can pretend to be a Wyse Thin client.

DHCP Request Option

This will only work when you have configured Global DHCP settings.

dhcptest.exe --query --request 161

DHCP Vendor Class

First I had to figure what the vendor class was. I checked this on the DHCP server:

Or on a Thin client itself:

Then run this command:

dhcptest.exe --query --option "60=wyse-1000"

And you will get Vendor Specific Information in Hex.

You can do different things to translate the Hex into readable data.

  1. Compile the open source yourself yourself and create a output in a string
  2. Use a (online) hex convertor
  3. Open wireshark during the capture. Wireshark will translate this for you 🙂

Compile the tool

  • Download the git repo
git clone https://github.com/CyberShadow/dhcptest.git
  • Edit the file (add these 2 lines)
161 : DHCPOptionSpec("File Server", OptionFormat.str),
162 : DHCPOptionSpec("Root Path to the File Server", OptionFormat.str),
dmd dhcptest.d

This will create a exe for you and will translate the Hex to readable format.

Happy sniffing!

Windows network package capture without installing anything (on the server)

I like Wireshark. But I don’t like to install software on a server for troubleshooting purposes. Especially when you need software like PCAP to sniff some network data.

But what you can do is capture data data with netsh, copy the data to your workstation, convert the data so you can read it with wireshark and do you thing.

Capture the data

Run this command to capture the data (elevated command prompt)

netsh trace start capture = yes ipv4.address = x.x.x.x

And stop the capture when you are done

netsh trace stop

Copy the files to you computer

Convert the capture

Download the etl2pcapng converter from the MS Github repo: https://github.com/microsoft/etl2pcapng

Convert the data

etl2pcapng.exe NetTrace.etl out.pcapng

You can open the out.pcapng file and do you thing.

Happy Troubleshooting!

Slow initial RDP connection

For me, this was a pain in the ass for a long time. When I connect to a Windows server through RDP/RDS it sometimes takes more than 2 minutes to connect to a server. Today after some waiting, and waiting and some more waiting I did a deep dive with Wireshark to figure out why it was so slow.

My setup

  • Azure domain joined Windows 10 device (Laptop)
  • Connection over a Cisco Anyconnect VPN
  • Remote Desktop Manager (Devolutions)
  • Native RDP client
  • MremoteNG

Remote VS local

I know for sure the issue should be in my setup. Because when I connect first to a jump host (RDP) and then connect to other domain-joined servers everything was connected almost immediately after I put in my user credentials.

What to do (TL;DR)

There are four things you have to modify to speed up the initial remote desktop connection speed:

  1. Disable SSL / TLS1.0
  2. Disable Netbios on the VPN network adapter
  3. Disable automatic proxy settings in Windows
  4. Change the credential to domain.local\admin or [email protected] instead of domain\admin

Disable SSL / TLS1.0

No, you don’t have to negotiate what protocol you have to use to connect a server. Use TLS1.2 or I don’t want to connect with you 😉 So:

How to

  • Start > Run > Regedit
  • Go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client
  • If the TLS 1.0 and Client folders doesn’t exists create these keys
  • Create a 32 DWORD value with the name Enabled
  • Value data: 0 (Hex)
  • Restart the client
Enabled = 0

Disable Netbios on the VPN adapter

What I was seeing in my Wireshark capture is that RDP was trying to broadcast to get information over NETBIOS. You have a DNS server so you don’t need a legacy broadcast protocol! Unfortunately, I don’t have any screenshot of the capture but you can always check yourself 😉

How to

Change the VPN Adapter and reboot the computer:

Disable Netbios

Disable the proxy

After connection to a server with RDP and you enter the credentials Windows is trying constantly to WPAD.domain.local to autoconfigure itself. WPAD stands for Web Proxy Auto-Discovery and I think you never want to autoconfigure a MITM ehh proxy device. You always want to have full control of your device. So, disable this to speed up the connection and make your device more secure.

Wireshark Capture WPAD A record

How to

  • Go to settings
  • Search for proxy
  • Switch the Automatically detect settings to Off
  • Restart Windows
Turn WPAD off

Change the login name

I found out that this is the most annoying and time consuming one. I always use DOMAIN\User when I connect to a server. But this is what happens:

Domain.Domain.TLD

Kerberos is doing a DNS query on _kerberos._tcp.dc._msdcs.domain.domain.tld and of course he will never can find that double domain A record. But if you change the logon name to domain.tld\admin or [email protected] Kerberos will find the A record and connects immediately 🙂

Top speed!

Kerberos

And even now it’s possible to tune the Kerberos authentication further and fix the last KRB5KDC_ERR_PREAUTH_REQUIRED error you can see in the screenshot. Maybe next time but for now I’m happy with the initial connection speed 🙂

Happy hack ehh… connecting!

OWASP ZAP Proxy with Android on Genymotion

It can be fun to reverse engineer some android applications. I think it’s better to do this on your workstation instead of your phone because it’s way more flexible and you don’t ruin your phone when you break things 😉

In my case, I use Debian 11. But of course, you can do this with any OS.

Requirements

  • An app you want to debug
  • OWASP ZAP Proxy
  • Genymotion
  • NPM
  • APK Export (Android App)

OWASP ZAP Proxy

I use the snap package for ZAP because it’s easy to install and you’ve always the latest version.

$ sudo snap install zaproxy --classic

Start ZAP and export the dynamic certificate (tools > options)

Dynamic SSL Certificate
  • Click on the save button an place the file somewhere on your disk.

You can check if the OWASP ZAP is running with:

$ netstat -tulpen | grep 8080
tcp6       0      0 127.0.0.1:8080          :::*                    LISTEN      1000       89190      14016/java

Genymotion

Now the proxy is in place it’s time to install genymotion for the android emulation. First install virtualbox.

Install virtualbox APT keys

$ wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
$ wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -

Edit the /etc/apt/sources file and add this line:

deb [arch=amd64] https://download.virtualbox.org/virtualbox/debian bullseye contrib

Update the repo and install virtualbox

$ sudo apt-get update
$ sudo apt-get install virtualbox-6.1
  • Now go the the genymotion website and download the latest bin file
Download Genymotion
  • Make the file executable and run the installer
$ chmod +x genymotion-3.2.1-linux_x64.bin 
$ ./genymotion-3.2.1-linux_x64.bin
  • Follow the wizards, create an genymotion account and create a new virtual device. In my example I used a google Pixel 3 with Android 10.
Overview virtual devices

Now it’s time to configure the proxy within the android device!

Configure proxy in Android

Start the created virtual genymotion android device and copy the certificate file we create earlier with a simple drag and drop.

drag & drop the certificate file
Succesfull copy
  • Now we can can configure the proxy in the wifi settings.
  • Go to settings > search for certificate and install the certificate.
settings > find >certificates
Import the certificate

Edit the wifi connection, add the proxy and restart the wifi.

  • Edit the Wifi
  • Go to the advance options
  • Set the proxy to Manual
  • The IP is always: 10.0.3.2 This is the “localhost” setting for the genymotion host server
  • Port 8080
Genymotion Proxy Settings

When you (re)connect the the wifi you have the accept the proxy error (but this is a good thing).

Sign in the the wifi
Accept the warning

Now you will see all the traffic. But only the traffic for the apps who respect the android HTTP_PROXY settings. So this is what you can do when an app don’t respect this setting:

Rebuild the APK with APK-MITM

Now everything is in place. So the last thing we need to do is rebuild the APK file so we can proxing all the network traffic. So:

  • First export the APK file trough the APK Export
  • Place the APK somewhere on your disk
  • Install npm (at least version 14)
$ curl -sL https://deb.nodesource.com/setup_14.x | sudo bash -
$ sudo apt-get install nodejs npm
  • Install java
$ sudo apt install openjdk-17-jre openjdk-17-jdk
  • And rebuild the APK
$ npx apk-mitm SomeAppName.apk
Some nice MITM patching

And here we go!

Everything is in place now. So the only thing you have to do is drag & drop the *-patched.apk file to genymotion, install this file and you are fully in control 🙂

ZAP Proxy with MITM Apk

Happy hacking!

Howto: Configure cloudflare for wordpress

My web hosting company don’t support subdomain SSL certificates. And because Google’s Chrome in July is required HTTPS on all websites (otherwise you get an error your website isn’t safe) I had some deadline to make my blog HTTPS. Cloudflare is a nice reverse proxy solution and the basic plan is free to use also.

So what I did was create a cloudflare account and put my website behind it. After I did that I forced the HTTPS and voila my website was HTTPS. The steps you must take.

Note: this trick will also work if you want to use cloudflare as a reverse proxy to prevent DDoS, to optimize your site security, hide your hosting party backend and make your website a lot faster. If you use a raspbery Pi for example at your home location you can put cloudflare between the visitor and your home IP and save you a lot of trouble.

  • If you use the wordfence plugin also be sure your PHP version is higher than 5.6. Otherwise you get some errors and conflicts (more info)
  • Go to cloudflare an create an account
  • Configure your DNS

  • (temporary) disable your DNSSEC at you domain if that is enabled (cloudflare cannot succesfully transfer your DNS otherwise). For me I had to create a ticket with my domain register company
  • Cloudflare give you 2 new name servers. Ask your domain registry company to change these DNS name servers if you can change it by yourself

  • After a succesfull DNS nameserver change cloudflare shows in the portal everything is ok:

  • Optimize your cloudflare for wordpress in the cloudflare wordpress plugin and enable HTTPS rewrites

  • Now edit your url in the settings >general in your wordpress

  • And finaly go to cloudflare and enable always uses HTTPS under crypto

Now everything is done and your website is fully HTTPS at the frontend (with automatic HTTP > HTTPS URL rewrites). Because my backend don’t have an SSL certificate all the data between cloudflare and my hosting company is still unencrypted. So this is a nasty workaround but you don’t have any problem with Chrome HTTPS problems in the near future anymore.

Create a strong self-signed certificate for multiple years

If you follow these steps you can create a self signed certificate with the following specifications:

  • Wildcard certificate
  • SHA256 hash
  • 10 years
  • 2048 bits public key
  • Client and server verification
  • Sha1 fingerprint

Be aware that self-signed certificates can manipulate by a man-in-the-middle. You should not use this in critical production environments.

Please use windows 10 powershell in admin mode. Otherwise you will get errors

New-SelfSignedCertificate -certstorelocation cert:\localmachine\my -dnsname *.domain.local -NotBefore $([datetime]::now.AddDays(-15)) -NotAfter $([datetime]::now.AddDays(3560))

Now export the certificates. Before you copy/paste change the thumbprint with the thumbprint you get from the above command.

$CertPassword = ConvertTo-SecureString -String "YourPassword" -Force –AsPlainText
Export-PfxCertificate -Cert cert:\LocalMachine\My\C6B46CEB7D3A40DB08E78B19FEDD3A24EA7A7919  -FilePath C:\test.pfx -Password $CertPassword
Export-Certificate -Cert Cert:\LocalMachine\My\C6B46CEB7D3A40DB08E78B19FEDD3A24EA7A7919 -FilePath C:\tstcert.cer

Now you can import the PFX with IIS and bind the certificate in IIS.
And import the *.CER in your MMC > Certificates > Computer account > trusted root Certification authority > Certificates

Have fun with your certificate the next 10 years 😀

command-prompt-powershell

Inspiration