Wednesday, September 6, 2023

Quick Malware Analysis: GOZI/ISFB INFECTION WITH COBALT STRIKE pcap from 2023-07-12

Thanks to Brad Duncan for sharing this pcap:

We did a quick analysis of this pcap on the NEW Security Onion 2.4. If you'd like to follow along, you can do the following:

The screenshots at the bottom of this post show some of the interesting alerts, metadata logs, and session transcripts. Want more practice? Check out our other Quick Malware Analysis posts at:

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First, we start with the overview of all alerts and logs:

Next, let's review the alerts:

Drilling into "ET MALWARE Ursnif Payload Request (cook64.rar)" alert, we see:

Pivoting to pcap, we see the full TCP stream:

Switching to the ASCII transcript shows the HTTP transaction more clearly:

Next, we drill into the "ET MALWARE Ursnif Payload Request (cook32.rar)" alert:

Pivoting to pcap, we see the ASCII transcript of the HTTP transaction:

Next, we drill into the "ET INFO Dotted Quad Host ZIP Request" alert:

Pivoting to pcap, we see the ASCII transcript of the HTTP transaction:

Next, we drill into the "ET MALWARE Ursnif Variant CnC Beacon 3" alerts:

Pivoting to pcap, we see the ASCII transcript of the HTTP transaction:

Next, let's review the protocol metadata:

Drilling into HTTP logs we see several POST requests going to foreign sites and we see the RAR and ZIP downloads noted earlier:

Drilling into SSL logs, we see lots of traffic going to a site with an interesting name:

Drilling into DNS logs, we see the DNS lookups for the interesting domain names noted earlier:

Finally, the connection logs include GeoIP lookups showing foreign countries noted earlier:

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