Wednesday, September 13, 2017

I Smell A RAT – Learning about Poison Ivy – Live Forensic Analysis

In this series of posts, I’m continuing the Open Security Training materials with this set of post being more focused on the Malware Analysis class.

You may find reviewing the material from Open Security more beneficial. However, if you do choose to stick with this I hope you find it helpful.

In this post we will take a quick pass at some live forensic analysis. See the reference section for some other analysis you may undertake.

First up, I’ll start off with the network through leveraging “netstat” on the “compromised” host. The network information below shows that the host “Securitynik-xp” on source port 1025 has an established connection to host on port 3460.

Now that we have an established connection, let’s see what is the PID and owning process of this connection. Leveraging the “neststat –ob” as shown below.

Above we see the owning process is “system32:secnik_piv.exe” and it has a PID of 1688.

By looking at the “:” in “system32:secnik_piv.exe” we can conclude that this is more than likely an Alternate Data Stream (ADS).

Doing a “dir c:\windows\system32\secnik*.exe” we see … basically the file was not found. In Windows XP there is no immediate way to detect ADS without third party tools.

Therefore let’s leverage Sysinternals “Streams.exe” to identify the ADS in “system32”. The image below shows that “secnik_priv.exe” is embedded in “c:\windows\system32”
Taking a look at the registry for persistence, we see the key "HKLM\software\Microsoft\windows\CurrentVersion\Run" has a value “SecurityNik_PIvy_Agent      REG_SZ  C:\WINDOWS\system32:secnik_piv.exe”

Taking a look at ProcessHacker to learn more about the process “system32:secnik_piv.exe”, we see that it was started by “explorer.exe”. We also see that this process has spawned a “cmd.exe” process. If we remember from this post, we were interacting with the “compromised host” via the command shell.
At this point, we can continue to leverage ProcessHacker or even identify additional tools which can assist with our live analysis.

However, we were able to identify it’s persistence mechanism which allows it to survive reboot. At this point we can take the next step which is to begin the clean-up process.

Let’s start with deleting the persistence mechanism via the registry using “reg delete "HKLM\software\Microsoft\windows\CurrentVersion\Run" /v "SecurityNik_PIvy_Agent"”
We see from the final entry above that "SecurityNik_PIvy_Agent” has been deleted.

Let’s now look at suspending the process “system32:secnik_piv.exe” before we attempt to delete it from the ADS.

Leveraging ProcessHacker once again we first suspend the process … 

… once suspended we then leverage GMER to delete the file as shown below …
If we take a look at “c:\windows\system32:secnik_priv.exe” with Sysinternals “streams.exe” we see the file no longer exists as show below.

Now let’s close this off by terminating the process tree for “system:secnik_priv.exe

At this point, consideration should be given to the fact that the process may be recreated, therefore close attention should be paid to monitoring. Additionally, you may want to monitor the network for traffic known to be associated with Poison Ivy. Restarting the “infected” system is a good way to verify that all is well.

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