In this lesson,
we're going to briefly cover the concept of log tampering
and how to use it in penetration testing,
with a focus on the use of PowerShell and PsExec.
Log tampering refers to the act
of modifying or deleting log files
to cover the tracks of an attacker.
During a penetration test,
understanding log tampering is essential
because logs are critical for forensic investigations
and monitoring unauthorized activities.
Attackers often attempt to tamper with logs
to avoid detection and hinder the investigation process.
So let's dive into the details.
When we talk about logs
in the context of penetration testing,
we are generally referring to logs
generated by operating systems,
applications and network devices.
These laws capture various events,
such as user credentials, file access,
configuration changes and network connections.
They provide a valuable audit trail
that can help identify suspicious activities
and potential security breaches.
Now let's discuss how attackers temper with logs.
They might delete specific log entries,
modify timestamps or alter log data to create false records.
These actions aim to remove any evidence of their presence
or to mislead investigators.
One common tool used for log tampering is PowerShell.
PowerShell can be used
to interact with the Windows event log,
which records significant system events.
An attacker with the right permissions
can use PowerShell to clear or manipulate these logs.
Here's an example of how an attacker might use PowerShell
to clear the Windows event log
with the clear event log command.
This script clears all entries in the specified event logs.
By doing this,
the attacker removes any traces of their actions
from the logs.
Another tool often used in log tampering is PsExec,
a remote administration tool
that allows users to execute processes on other systems.
With PsExec, an attacker can run PowerShell scripts
or other commands on remote machines.
Here's an example of using PsExec
to run a PowerShell script on a remote machine.
Now, in this example,
PsExec is used to run a PowerShell command
on a remote machine
to clear the security event log.
With the -s option,
runs the process as a system account,
which typically has the necessary privileges
to clear event logs.
So, why is log tampering important
for penetration testers to understand?
Again, knowing how attackers tamper with logs
allows penetration testers
to better protect these crucial data sources.
They can implement measures
to detect and prevent log tampering,
such as using log integrity and monitoring tools,
setting up alerts for suspicious log activities
and ensuring that logs are securely backed up and stored.
So remember, log tampering
is a critical aspect of penetration testing.
It involves manipulating or deleting log entries
to hide unauthorized activities.
Tools like PowerShell and PsExec
are commonly used for this purpose.
Understanding these techniques
allows penetration testers to better secure log data
and ensure the integrity of their forensic investigations.