Monday, August 3, 2015

More artifacts through PowerShell - Part 5

MS Office Trust Records.

When documents are downloaded from untrusted sources, a "trust" prompt is shown to the user when the user wants to edit the document. The full path of the document is saved under the below registry key when this happens.

Software\Microsoft\Office\*\PowerPoint\Security\Trusted Documents\TrustRecords (* should be replaced with the version of the MS Office installed in the system but for PowerShell gathering, we can still use the * as shown below:)

gp hkcu:'\Software\Microsoft\Office\*\Excel\Security\Trusted Documents\TrustRecords' | select * -ExcludeProperty PS*
gp hkcu:'\Software\Microsoft\Office\*\PowerPoint\Security\Trusted Documents\TrustRecords' | select * -ExcludeProperty PS*
gp hkcu:'\Software\Microsoft\Office\*\Word\Security\Trusted Documents\TrustRecords' | select * -ExcludeProperty PS*

Want to see all with one command?

gci -r hkcu:'\Software\Microsoft\Office\*\*\Security\Trusted Documents' | select -ExpandProperty Property


Decrypting UserAssist key entries.

Forensic use of UserAssist keys are well known. It primarily stores information about actions the user took with the Shell; actions such as starting applications, double clicking shortcuts, etc. Entries in the UserAssist keys are ROT13 encrypted, the encrypted entries can be viewed by issuing the following one liner.

gp "hkcu:\Software\Microsoft\Windows\Currentversion\Explorer\Userassist\*\Count" | ft -auto -wrap

In order to decrypt the entries, we can use the function provided in this blog.


Chrome Local Storage entries.

Local storage in Chrome browser is part of HTML5 specification; it is designed to store persistent data (even after the browser is closed) local to the system such as the cookies. This is in SQLite format but can be accessed through PowerShell to get a rough idea about the web sites visited.

Here is the one liner for this:

dir $env:LOCALAPPDATA\'Google\Chrome\User Data\Default\Local Storage' | Sort-Object LastWriteTime -desc


Saturday, July 4, 2015

More artifacts through PowerShell - Part 4

Typed URLs - alternate location.

The main script LRUP already contain many IE related artifacts; here is one more that we can add to the list.
Under APPDATA, the system keeps a log of the URLs typed into the address bar to provide auto suggestion of the URLs that are being typed in. This log can be viewed using the Get-Content CmdLet.
     gc $env:LOCALAPPDATA\temp\structuredquery.log

DLLs and vendor information.

If you need to filter out the DLLs identified in the system that are non-Microsoft related, use the below one liner. For more information, check Trevor Sullivan's article.

$ProcExes = Get-WmiObject -Class CIM_ProcessExecutable; foreach ($item in $ProcExes) {[wmi]"$($item.Antecedent)" | ? { $_.Manufacturer -ne 'Microsoft Corporation' } | select FileName,Extension,Manufacturer,Version |ft -auto -wrap}

Application Compatibility related.

Application compatibility is a feature that can make older programs that have compatibility problems work better in Windows 7 and Windows 2008 operating systems.

System tracks the programs installed under the below registry key. Note that it "stores the list of all programs for which it came up under the following key for each user, even if no compatibility modes were applied (e.g. in the case where the user reported that the program worked correctly)"  - MSDN link 

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Compatibility Assistant\Persisted

In PowerShell, this can be gathered through the following one liner:

gp hkcu:'\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Compatibility Assistant\Persisted' | select * -ExcludeProperty PS*

Since it is taken from HKCU location, it is an indication that the particular user ran these programs. 


Sunday, June 28, 2015

More artifacts through PowerShell - Part 3

The main LRUP code lists many event logs that are useful in an incident response scenario. In this section, let's look some additional event logs that are going to be useful to collect.

Firewall related.

The below log shows the firewall rule changes and other actions such as profile changes.

Get-winevent -logname "Microsoft-Windows-Windows Firewall With Advanced Security/Firewall" | ft -auto -wrap 

Network related.

The below log shows the time when a network is changed from a home network to office network.

Get-winevent -logname Microsoft-Windows-BranchCache/Operational  | ft -auto -wrap

The below log shows when a network connection was made. 

Get-winevent -logname Microsoft-Windows-NetworkProfile/Operational  | ft -auto -wrap

Below log should be checked to see the RDP logins. More information on the event IDs is available at this MS link.

Get-winevent -logname Microsoft-Windows-TerminalServices-LocalSessionManager | ft -auto -wrap

Driver related.

Looking at the below log helps identify code integrity issues related to bad drivers or unsigned drivers. More information is available at this MSDN link.

Get-winevent -logname Microsoft-Windows-CodeIntegrity/Operational | ft -auto -wrap

Speaking of drivers, we can use the below command to get a listing of PnP related driver information.

Get-WmiObject -Class Win32_PnPEntity | select Caption,Name,Service

When a device is attached the computer, Windows attempts to detect the device type and install the appropriate driver so that it can communicate and control the device.

Completion of a device driver installation attempt gets recorded as an event ID 20001 message in the 'System' event log. The message provides device identification information and a status code for the device installation process. Devices that install successfully log an Event ID 20001 message with a status code of 0. To see this event, we can use the below one liner.

Get-WinEvent -ea 0 -FilterHashtable @{Logname='system';ID=20001} | select TimeCreated,ID,Message |ft -auto -wrap

Sunday, June 21, 2015

More artifacts through PowerShell - Part 2

Quickly identify a login event.

    Get-WinEvent -FilterHashtable @{Logname='security';ID=4624} | ft -auto -wrap

Quickly identify a login event for a particular user.

   Get-WinEvent -FilterHashtable @{Logname='security';ID=4624} | where {$_.message -like ‘*john*’ } | ft -auto –wrap

Quickly identify a login event for multiple users.

   Get-WinEvent -FilterHashtable @{Logname='security';ID=4624} | where {$_.message -like ‘*john*’ -or $_.message -like ‘*jane*’} | ft -auto –wrap

Quickly identify login events between two dates.

  Get-WinEvent -FilterHashtable @{Logname='security';ID=4624 ;StartTime="5/1/15";EndTime="5/31/15"} | ft -auto –wrap

Login events for a particular user between two dates.

  Get-WinEvent -FilterHashtable @{Logname='security';ID=4624 ;StartTime="5/25/15";EndTime="5/30/15"} | where {$_.message -like ‘*john*’ } | ft -auto –wrap

Quickly identify error events for previous day.

  Get-EventLog -LogName System -EntryType error -After (Get-Date).AddDays(-1) | ft -auto -wrap

Error events for a specific source such as NETLOGON

  Get-EventLog -LogName System -EntryType error -Source NETLOGON -After (Get-Date).AddDays(-1) | ft -auto -wrap

As a reminder, you can export any of these into a text file with the 'out-file' option; an example:

  Get-EventLog -LogName System -EntryType error -After (Get-Date).AddDays(-1) | ft -auto -wrap | out-file c:\event.txt

Saturday, June 20, 2015

More artifacts through PowerShell - Part 1

Identify currently logged in user.

If the requirement is to get only the logged in user along with the time of login then use "whoami' or "quser".

To see the privileges assigned for the currently logged in user.

whoami /priv /fo csv | convertfrom-csv | ft -auto -wrap

To identify the user profiles created.

User profiles can be checked by looking at the below registry location using Get-ItemProperty CmdLet.

Get-ItemProperty hklm:'\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList\*' |Select-Object PSChildName, ProfileImagePath | ft -auto -wrap

To identify users and processes that were started.

There are multiple commands that can be used but the builtin command 'qprocess' is the optimal one. It is similar to tasklist, but produces better output. It shows username, session id, pid, and image name.

Another useful command is 'qwinsta'. This builtin command shows RDP sessions as well.

'quser' is another useful command; this shows the logged in users, session name, time, etc. This command is extremely useful in a server environment.

To see if the user is part of administrator group.

net localgroup administrators .This command will show all the users that are part of the group 'administrators'.

Sunday, June 7, 2015

PowerShell updates

Have received many questions offline on the use of PowerShell and how we can get the desired artifacts from Windows system. While I have responded to most of those, I haven't gotten opportunity to update them here. I will try and update them here in a series of posts in the coming days.

The commands and options I will be posting are to be used in addition to the already published commands in the LRUP code and the SANS paper.

LRUP code is available here.

Monday, September 30, 2013

Howto - Creating a ZIP file of LRUP outputs

One of the requests I got was to combine the output of all the text files and compress it so that a single file can be sent by the user from their machine to the IR analyst.

If you want to use an external tool like 7-Zip that can be processed from the command line, it is easy to implement. However, if you want to use an in-built tool or script then there are multiple options.

There is a CodePlex project for this, check out

As an another option, take a look at David Aiken's post from MSDN.

Relevant portions of the code along with the option to combine the various text files is listed below:

function New-Zip
set-content $zipfilename ("PK" + [char]5 + [char]6 + ("$([char]0)" * 18))
(dir $zipfilename).IsReadOnly = $false

new-zip $UserDirectory\desktop\$CompName-$User-$

function Add-Zip

if(-not (test-path($zipfilename)))
set-content $zipfilename ("PK" + [char]5 + [char]6 + ("$([char]0)" * 18))
(dir $zipfilename).IsReadOnly = $false

$shellApplication = new-object -com shell.application
$zipPackage = $shellApplication.NameSpace($zipfilename)

foreach($file in $input)
            Start-sleep -milliseconds 500

gci $UserDirectory\desktop\$CompName-$User-$Date-Level1.html | add-Zip $UserDirectory\desktop\$CompName-$User-$

gci $UserDirectory\desktop\$CompName-$User-$Date-HostsFile.txt | add-Zip $UserDirectory\desktop\$CompName-$User-$

gci $UserDirectory\desktop\$CompName-$User-$Date-OpenFiles.txt | add-Zip $UserDirectory\desktop\$CompName-$User-$

gci $UserDirectory\desktop\$CompName-$User-$Date-AuditPolicy.txt | add-Zip $UserDirectory\desktop\$CompName-$User-$

gci $UserDirectory\desktop\$CompName-$User-$Date-FirewallConfig.txt | add-Zip $UserDirectory\desktop\$CompName-$User-$

#Clean-up routine

rm $UserDirectory\desktop\$CompName-$User-$Date-Level*.html

rm $UserDirectory\desktop\$CompName-$User-$Date-*.txt

Friday, August 30, 2013

LRUP Code published

Code used in the paper is now available from the CodePlex site.

This is a version 2.0, which is optimized for PowerShell V2. All new updates will be available at the CodePlex site from now on.

Comments and suggestions can be posted here.

Friday, August 23, 2013

SANS Gold paper on PowerShell

I have been working on a paper for the SANS Gold certification. The topic I chose was Live Response using PowerShell.

It was a great experience writing it and learning a great deal of  stuff on Windows operating system and PowerShell.

Finally, early this week I got the confirmation from SANS that it has been approved and published.

Paper is available on SANS reading room web site and direct download is available here.

Look for more details on the code and other developments in later posts.

Saturday, July 27, 2013

Programming knowledge in the field of DFIR

Harlan recently blogged about programming knowledge in DFIR field, link is here. It made me realize my own experience in scripting and how it helped gain more knowledge.

I started learning Unix shell scripting when I was working as a system administrator. For sysadmins it is an invaluable tool to automate both simple and complex tasks. Later, as a network administrator, scripting knowledge came handy in automating tasks such as device monitoring using SNMP, configuration  backup, making simple configuration changes, log analysis, etc.

When I moved to the DFIR field many years ago, scripting knowledge came handy particularly in log analysis. When you have month's of apache, proxy and firewall logs to sift through, knowledge of scripting becomes extremely handy. Other areas it is useful include PCAP analysis, Snort device management, manipulating outputs from scanning tools such as NMAP, getting system statistics, doing quick analysis of a system during or after an incident, forensic analysis, etc.

In order to make a script or program to work, you need more understanding of the system and in that process you seek more knowledge. In my view it helps you immensely in any area of work as technology professionals. As Harlan pointed out, you don't need to be an expert programmer, you just need to know the fundamentals and an aptitude for learning. With that basic knowledge, when there is a need to do something that is not currently supported or offered by existing tools you can create your own steps to achieve that task. It may not look pretty in the eyes of an expert programmer but as long as it can satisfy your requirement, you are good to go.

If you are a Unix person, start with shell scripting and then learn Perl and/or Python. If you are a Windows person, PowerShell is an extremely useful tool or scripting language to automate multitude of tasks. It is getting more popular as Microsoft bundles it with most of their new products. If you are from a Unix shell scripting background, it would be real easy to learn PowerShell as they use the similar concepts. Even otherwise, it's a simple language to learn.

As scripting and automation is a subject of immense interest to me, I started learning PowerShell a while ago. I hope to show some of the usefulness of PowerShell in coming weeks.