VBA in Excel is very helpful since it can run things without any human intervention, or technically it can run task and automate things and just get the result.
VBA coupled
with PowerShell can even be more interesting. Of course, there is always some
drawback or pros and cons.
Bad actor
can take advantage of VBA and PowerShell to run malicious software on user’s
computer.
For most
users who are not aware or doesn’t believe that VBA and PowerShell can be used
to steal data, one common reaction is; Is it possible? Or you are just trying
to exaggerate and scare people?
As the odds
say, to see is to believe. Or to see it in action is one thing and trying to
educate users is another thing. Cyber Security is a task that everyone should
be a part of, a chain is useless if one its link is weak. Which is basically,
true in digital world.
The company may spend thousands of moneys on Firewall, Anti-Virus and other devices
or software to thwart attack but just a simple click on a Phishing email of an unaware
email user will defeat all security measures.
VBA code
below, shows on how to use PowerShell on Excel VBA.
Sub vba_powershell()
Dim varx As String
Dim wshell As String
'Code below will minimized all
open windows
varx = Shell("PowerShell (New-Object -comobject
Shell.Application).ToggleDesktop()")
'This will open Notepad
wshell = Shell("PowerShell (New-Object -ComObject
wscript.shell).run('Notepad')")
'Wait for 5 seconds
Application.Wait DateAdd("s", 5, Now)
'Send the string to Notepad
Application.SendKeys ("Hello, be careful of opening files with Excel Macros!")
'This will open c:\Temp folder
'A network location can be used by replacing with a UNC path such as: \\server01\sharefolder
wshell = Shell("PowerShell (New-Object -ComObject
Shell.Application).open('C:\Temp')")
End Sub
Above code
is quite friendly but of course, it can be tweaked and change the code to download a malicious file
from the internet, or run a malicious app that is already on the hard drive. Never run an Excel macro that is not trusted, or just out of curiosity and take the risk.
Some users think that the anti-virus or other security measures set on the network will do its job and they will be totally protected, such mindset will wreak the whole company network. Malicious code that has not been detected, newly found security hole or any bug that is not yet known, can be exploited by bad actors and all security measures can easily be bypassed.
Cheers...till next time. Stay safe and keep praying that this pandemic will end.
================================
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Good article. I would just like to underscore your point about the importance of never running macros from sources you don't know / do not trust. I would also add that, looking at the code above, powershell isn't even needed - VBA can do all of that by itself without have to rely on Powershell!
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