How to Disable Antivirus Software on a friends pc to help him uninstall antivirus
In each case, we've embedded a listener/rootkit that gives us control
over the system. Metasploit has a powerful listener called Meterpreter
that enables us to control the system, send more commands, pivot from
the victim to other systems, elevate our privileges, and many other
things, as we will see.
Today, we will focus on how
to use the Meterpreter to disable the antivirus protection on our victim
system, which is more advanced than simply bypassing the anti virus program. Disabling is necessary because the next time the system is scanned by
the victim's antivirus software, it's likely to detect our listener and
disable it, so we need to take preemptive action to disable it before it
can disable us.
I'm assuming you have
already embedded your Meterpreter listener by one of the many methods
I've outlined in my earlier posts, and that you have a Meterpreter
prompt as it appears in the screenshot below.
Before we can begin to kill the AV software, we need to escalate our privileges.
Usually,
when we embed a listener on the victim's system, the listener will only
have the privileges of the user who provided us with a gateway to their
system by clicking on the malicious website, Office doc, Abobe PDF, etc.
That
user most often has limited rights or privileges to the system.
Unlimited rights to do anything on the system is held by the
administrator or system administrator (or sysadmin for short).
We need to escalate our privileges from the user to sysadmin to have our way with this computer.
Step 2: Checking the User
Before we start the process of escalation, let's check what user we are logged in as. Type: meterpreter > getuid
This
will return the ID of the user we are logged in as. If we are anything
but the sysadmin, we'll need to escalate to kill the antivirus software.
Step 3: Escalate Privileges
Metasploit and its Meterpreter make it simple to escalate privileges to the sysadmin. Simply type getsystem at the Meterpreter prompt. meterpreter > getsystem
Notice that Metasploit responds with "...got system (with technique 1)". Metasploit has multiple methods to escalate privileges and it tries each of them out until one works.
In our case, it was successful with technique 1.
Step 4: Check That We Are Sysadmin
Now that Metasploit has told us that it has escalated our privileges to sysadmin, let's make sure. Type: meterpreter > getuid
As you can see in my screenshot above, the victim responds with NT AUTHORITY\SYSTEM, the syadmin user!
Congratulations! You can now have your way this victim.
Step 5: Kill the AntiVirus Software
Now that we have unlimited rights to this system, let's kill the antivirus software. Metasploit has a Ruby script called killav.rb. We simply run that script from the Meterpreter prompt and it will kill the system's antivirus software.
Make certain to start the script with the keyword run. Type: meterpreter > run killav.rb
Notice
from the screenshot above that the killav.rb script not only killed the
antivirus process, but also the open command prompt.
Now
that we have killed the antivirus process, we can remain hidden within
their system and do as we please with little or no chance of being
detected.
In upcoming blogs, we will explore more adventures with
the power of our embedded listener/rootkit with sysadmin privileges.
There is no limit what we can do now
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