Capturing Pcap driver installations

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Today we're looking at Network Sniffing, ATT&CK technique T1040.




This is very much a signature based rule but if you are ingesting WinEventlog:Security (and of course you are, right?) and specifically EventCode 4697 ("A service was installed in the system") then you can take the barebones splunk SPL from below and make it work for you.

So how are we going to detect network sniffing on Windows endpoints? The installation of the drivers for the various Pcap variants.


index=win10 sourcetype="wineventlog:security" EventCode=4697 AND Service_File_Name IN ("*pcap*", "*npcap*", "*npf*", "*nm3*", "*ndiscap*", "*nmnt*", "*windivert*", "*USBPcap*", "*pktmon*")
| table _time Account_Name Computer_Name Originating_Computer Service_Name Service_File_Name
 

The Service_File_Name list is derived from looking at the names of .sys files associated with the most popular packet capture options for Windows, it'll need to be kept up to date and less commonplace or renamed drivers may well slip through the net.

I installed AirPcap 4.1.3 and Win10Pcap on my test VM and both were caught by the above SPL.




Happy hunting.

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