Cloaking and Alternative Data Streams: Hide an Executable inside a Text File

How to Hide an Executable File Inside and Text File

Did you know that hackers can hide an executable file inside of a text file using a technique that uses something called data streams to trick a computer system from seeing text and or executable written in an alternate data stream inside a common text file.

I was pretty impressed the first time I watched someone demonstrate this. I was like, NO WAY! I really thought that this was some wizard level hacker stuff.

I’m no wizard level hacker, although I aspire to be, but I should be good enough to show you how to embed a simple calculator app inside a text file using an alternate data stream.

A big thank you to Cyber Security Expert, Malcolm Shore who presented a similar example in his Cyber Security Foundation online course I recently completed.

How Do Alternate Data Streams Work?

Way back in the old Wild West days when we had the DOS operating system, files used to be simple strings of data. Files are read btye by byte.

Later, in the NTFS file system, files are complex structures. NTFS files at a minimum contain a section called $Data where data is read by an application. $Data is the Data Stream.

Files may have many other sections or streams other than just the $Data section. This is what we call “Alternate Streams”.

THIS IS IMPORTANT: Windows only recognizes data in the $Data section so any data we put in an alternate data stream is not read by the Windows Operating System. We cloak data we want to hide in an alternate data stream. That’s the basics of how this works.

The data we are hiding could be a malicious malware payload or encrypted espionage message for our spy ring but in this example, it is just the simple calc.exe file you can find on any Windows PC for the last 20+ years.

Creating an Alternate Data Stream in a Text File

The screenshot below shows the three (3) files we’ll be using in this demonstration.

  • Simple text file with some string data.
  • calc.exe application or executable binary file
  • Secret text file with some string data

We can see the size of the text file is just 1 KB and the calc.exe file is 897 KB.

If we open the text-data.txt file with Notepad we’ll see just a simple line of text and the same with the secret-data.txt file.

To hide our secret message inside the the text data file, we’ll use this command line command.

C:\text\>type secret-data.txt > text-data.text:hidden.text

Screenshot of Alternate Data Stream: Insert Hidden Text

Below is a screenshot of the command line command “type” that we used in this example to insert our secret-data.txt file into an Alternate Data Stream inside of another text file.

If we type the command “more” we can look for the secret message.

The screenshot below shows the text file that contains our hidden text being opened in Notepad where we can’t see the hidden text we saved to the file. If we type the command line command below, we can read the hidden text we wrote to our Alternate Data Stream by keying in on the specific data stream.

c:\test>more < text-data.txt:hidden:text
Screenshot: Display hidden text in a text file.

Hiding an Executable Inside a Text File

Hiding an executable file inside a text file using the exact same Alternate Data Stream technique we just used in the the Secret text file example above but this time we’ll simply replace the Secret text file with the Windows Calculator application executable file.

The screenshot below shows the command line command to save the calc.exe file in an Alternate Data Stream in side our target text file.

Notice this time, the Alternate Data Stream is named “mycalc.exe”. Don’t get to hung up on this, it is just a name that is basically meta data that is saved with the data that we can use to filter the data we get out of the file. I hope that makes sense.

Important to note at this point that the file sizes didn’t change when we inserted the calc.exe file. It is still showing 52KB.

How to Execute a File Saved in an Alternate Data Stream

To execute a file you’ve stored in an Alternate Data Stream, we’ll need to use the wmic command as is done in the following example.

c:\test>wmic process call "c:\test\text-data.txt:mycalc.exe"

As you can see from the working example above, I was able to embed the calc.exe file inside as well as text file and a secret message.

If the data is text we just need to indicate which stream we saved the data in to retrieve it.

If the data we hid was an executable file, we’ll need to use the Windows “wmic” command line command to call the executable from inside the text file by keying in on the Alternate Data Stream name.

In summary, the technique is crazy easy to pull off without any 3rd party hacking tools. It just requires a little Windows Operating System inside knowledge but is something every good hacker should know.

I hope this helped somebody!
~Cyber Abyss

How to Transfer Files from Windows PC to Linux Server Using Putty’s PSCP Command

Many blogs and web applications are being hosted on cloud based web servers. Of those web servers, many are running some flavor of the Linux operating system (OS).

If you’re a Windows PC user who is using a Linux web server for your online project then you have unique challenge that comes with being a dual OS user.

How will we transfer our files from our Windows development PC to our Linux cloud hosted blog or web app? Enter Putty and the PSCP command line tool!

What is Putty?

Putty is a Client application that handles connections to remote computers via the Telnet, SFTP and SSH protocols.

Putty Screenshot

What is PSCP?

PSCP is a command line application that is typically included in the Putty installation. PSCP transfers files between two computers from the Windows command line as long as firewalls allow the traffic on the designated ports for each type of traffic.

Transferring Files with PSCP from the Command Line

If you’ve installed Putty in the default directory, it will be here.

C:\Program Files\PuTTY

Open a Windows command line by clicking on the Windows start menu icon then entering “cmd” in the search field then find and click on the cmd icon.

Navigate to the Putty Directory by entering the command below.

C:\>CD c:\Program Files\Putty

Let’s look at an example PSCP command to transfer a file from a Windows PC to a Linux cloud web server with a fake user named root, IP of 45.99.99.99 and a target folder of /var/www/html

PSCP Command Example

c:\>C:\Program Files\Putty\pscp c:\temp\sample.txt root@45.99.99.99:/var/www./html

Screenshot

That’s all you should need to know about connecting to a Linux cloud based web server from a Windows PC using the Putty SSH client.

Hope this helps you on your Cyber journey!

~Cyber Abyss

How to Build Your Own Website Uptime Monitoring Script using VBScript: Part 1

Website Uptime Monitoring: The Basics

There are lots of website uptime monitoring services out there but all the components you need to build your own website monitoring tool can be found in good ole’ Microsoft VBScript.

Stop laughing, I’m not kidding!

In this article, I’ll share with you some scripts and tips I’ve used successfully in the past for monitoring website uptime even if your website is running in a complex load balanced enterprise environment which some of mine are.

VBScript Components for Uptime Monitor

Most people don’t know that VBScript can make Ajax HTTP calls but it can.

We will use VBScript’s ability to make Ajax HTTP calls to our website to see if it responds then put some simple logic around that response to log the results in a text/csv file.

It really is amazingly simple once you get all the code components together.

The ISWebSiteUp Function

The ISWebsiteUp function takes a URL string and makes an Ajax HTTP call to see if we get a HTTP code 200 or 404 returned meaning website loaded OK.

Once we get our 200 or 404 HTTP response code that, script returns true in the form of a text message box or if script times out you’ll get a false in an error message box.

You might be saying to yourself about now, what about the 404 response code for page not found. Yes, you might want to add some more code to handle that differently than a 2oo OK response but for this script, we just want to know if server is up. If we are pointing to a page at the root of a domain, we don’t typically get 404 errors in reality.

The Script Code

To use this code, copy it in to a text file and save it with a .vbs file extension for VBScript. Once you have the .vbs file, double click on it and you should get a message box with the names of the logged in user on the specified Windows PC on your network.


'isWebsiteUp: Takes String URL 
'isWebsiteUp: Returns strMessage in Message Box
Function isWebsiteUp(strURL)

	On Error Resume Next

	Set http = CreateObject("MSXML2.ServerXMLHTTP")
 	'Set http = CreateObject("Microsoft.XmlHttp")
	http.open "GET", strURL, False
	http.send ""

	'Only check for error of the HTTP Get request for 200 or 404 code returned. If any status is returned then the server is up
	if http.responseText <> "" AND err.number = 0 then
		'Commented out showing the response text. Use this for troubleshooting or exploring.
		'msgbox(http.responseText)
		isWebsiteUp = true
		strMessage = "is up"
	else
		isWebsiteUp = false
		strMessage = "is down"
	end if
	Set http = Nothing	

	msgbox(strURL & ":" & strMessage)
	err.clear
End Function

call isWebsiteUp("https://www.google.com") 

What the Web Server Sees in the HTTP call: WinHTTPRequest User Agent

The VBScript Ajax HTTP call to the web server presents itself as a web browser asking for the home page.

In the server logs a server admin may see this “User Agent” in their logs.

Mozilla/4.0 (compatible; Win32; WinHttp.WinHttpRequest.5)

Script Errors & Blocked HTTP Calls

This script works out of the box. Google is the most open website in the world in terms of IPs that their servers accept traffic from as they are in the business of collecting data about everything including every system that connects to it.

Other web servers, like ones I run, may not be so forgiving. Many server admins use many tools at their disposal to filter HTTP request at various levels.

Here are some examples of tools Windows Server Admin have at their disposal to block or filter your script from connecting to their web servers.

Windows Server Admin Tools for Handling HTTP Traffic

  • Firewall IP Restrictions (Window Server Admin)
  • HTTP Response Filtering (IIS Application Server Admin)
  • IP Restrictions (IIS Application Server Admin)

Google Dorking? Yeah, it’s a thing. Search Google for Hidden Files

Let me start by saying the title might be a little off, as the files are not technically hidden as much as they are obscure.

While most of us would consider ourselves pretty good Googler searchers these days but the truth is, there is so much more to Google searching than meets the eye.

Introducing… “Google Dorking”

Yes, I said it Google Dorking and it’s not what you might think. Sounds dirty, right? It’s not just me. LOL

Google Dorking also known as Google hacking is about searching Google in a way that filters and brings all sorts or OSINT and InfoSec goodies floating to the top.

Think Before You Dork!!!

Although the information my be available on Google, it does not mean you can use that information to try and hack or gain unauthorized access to a system or individual computer.

Hacking is illegal, don’t do it, don’t talk about it.

With that being said, please be careful, be responsible and please enjoy these Google Dorking Examples for educational purposes.

Searching Google for user names and password in log files

allintext:username filetype:log

Searching Google for Open FTP Servers

intitle:"index of" inurl:ftp

Searching Google for Open Web Cams

Intitle:"webcamXP 5"

inurl:view/index.shtml 

Searching Goolge for Database Passwords

db_password filetype:env

Searching Google for Git-hub Resources

filetype:inc php -site:github.com -site:sourceforge.net

Searching Google for PHP Variables

filetype:php "Notice: Undefined variable: data in" -forum

Search Google for Server Configuration Files

intitle:"WAMPSERVER homepage" "Server Configuration" "Apache Version"

Search Google for Nessus Scan Reports

intitle:"report" ("qualys"|"acunetix"|"nessus"|"netsparker"|"nmap") filetype:pdf

Search Google for Networking Xls Files

ext:xls netoworking

Search Google for FrontPage Servers w/ Admin Info

"#-Frontpage-" inurl:administrators.pwd

Search Google for Unprotected Cameras

inurl:view/index.shtml

Search Google for Hidden Login Pages

Username password site:com filetype:txt DomainName.com

Google Dorking Video by Null Byte

Hope this helps somebody!
~Cyber Abyss

VBScript WMI: How to Get Computer Serial Number from Local or Remote Windows PC

This Windows WMI script using VBScript, retrieves the serial number of the local or networked computer.

To use this code, copy it in to a text file and save it with a .vbs file extension for VBScript. Once you have the .vbs file, double click on it and you should get a message box with the names of the logged in user on the specified Windows PC on your network.

Windows WMI VBScript

Function GetComputerSerialNumber(strComputer)
	Set objWMIService = GetObject("winmgmts:" _
		& "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2") 

	Set colComputer = objWMIService.ExecQuery _
		("SELECT * FROM Win32_ComputerSystemProduct",,48)
	 
	For Each objComputer in colComputer
		GetComputerSerialNumber = objComputer.IdentifyingNumber
	Next	
	
End Function

'strComputer = "XPS1234"
strComputer = "."

' Pass a . to run this on your own PC or add a string value for another on your network
call msgbox(GetComputerSerialNumber(strComputer))

VBScript WMI: How to Get Logged in User from a Windows PC

If your in need of finding out who is logged on to a specific Windows PC on your network, run the VBScript below.

When executed, you’ll see a message box with the name of the account currently logged in the computer specified.

The VBScript Code

To use this code, copy it in to a text file and save it with a .vbs file extension for VBScript. Once you have the .vbs file, double click on it and you should get a message box with the names of the logged in user on the specified Windows PC on your network.

Function GetLoggedinUser(strComputer)
	Set objWMIService = GetObject("winmgmts:" _
		& "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2") 

	Set colComputer = objWMIService.ExecQuery _
		("Select * from Win32_ComputerSystem")
	 
	For Each objComputer in colComputer
		Wscript.Echo "Logged-on user: " & objComputer.UserName
	Next	
	
End Function

' Pass a . to run this on your own PC or add a string value name for PC on your network
'strComputer = "XPS1234"
strComputer = "."

call msgbox(GetLoggedinUser(strComputer))

Stay tuned for more scripts in upcoming blog posts!

Hope this helps somebody!
~Cyber Abyss

VBScript WMI: Get List of Administrators from Windows PC

I’m breaking down a large VBScript I wrote as part of a larger computer inventory system prototype I built for what later became a much larger company.

This project was a big time investment for me that provided a lot of value to the company until they went out and purchased a commercial product and even then, the commercial product had things it did not do as well as my prototype.

The scanning volume eventually got so big that I had to run copies of the script on different parts of Active Directory at the same time to try and scale the scanning of computers on the network with all the data being stored in a SQL database backend.

This script and others I’ll be sharing in this series were contained within a loop of Active Directory computer records for a good size enterprise with about 10,000 desktops and laptops for some Active Directory OUs.

This script leverages Windows Management Instrumentation (WMI) to query what’s going on with this Windows network PC.

The first piece of code I’m sharing is for querying the Windows WMI to get a list of Administrators from a Windows PC. This code was used as part of a project to determine if any computers had unauthorized admin accounts we didn’t know about.

GetAdminstrators Function

To use this code, copy it in to a text file and save it with a .vbs file extension for VBScript. Once you have the .vbs file, double click on it and you should get a message box with the names of the admin accounts from the target device.

Function GetAdministrators(strComputerName)
On Error Resume Next

    Dim objWMIService, strQuery, colItems, Path, strMembers, strAdminList, iCounter
	iCounter = 0
    Set objWMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\" & strComputerName & "\root\cimv2")
    strQuery = "select * from Win32_GroupUser where GroupComponent = " & chr(34) & "Win32_Group.Domain='" & strComputerName & "',Name='Administrators'" & Chr(34)
    Set ColItems = objWMIService.ExecQuery(strQuery,,48)
    strMembers = ""
    For Each Path In ColItems
		Dim strMemberName, NamesArray, strDomainName, DomainNameArray
        NamesArray = Split(Path.PartComponent,",")
		strMemberName = Replace(Replace(NamesArray(1),Chr(34),""),"Name=","")
		DomainNameArray = Split(NamesArray(0),"=")
        strDomainName = Replace(DomainNameArray(1),Chr(34),"")
        If strDomainName <> strComputerName Then
            strMemberName = strDomainName & "\" & strMemberName
			if iCounter = 0 then
				strAdminList =  strMemberName
			else
				strAdminList = strAdminList & " > " & strMemberName 
			end if
			iCounter = iCounter + 1
			
        End If
	Next
	
	GetAdministrators = strAdminList
End Function
' Pass a . to run this on your own PC or add a string value for another on your network
call msgbox(GetAdministrators("."))
call msgbox(GetAdministrators("NetworkComputer1"))

Stay tuned for more scripts in upcoming blog posts!

Hope this helps somebody!
~Cyber Abyss

Joining MP4 Files Together Using the Windows Command Line

I have two MP4 files that I need to merge together into one single file.

You might think that you would need a special piece of software to combine two MP4 video files but all it takes is a single command from the Windows command line to do the job.

copy /b "C:\File1.mp4" + "C:\File2.mp4" NewCombinedMoveFile.mp4
 

That’s it, that’s all it takes to combine two MP4 movies files in to one since file.

Hope this helps sombody!

~ CyberAbyss