[SANS ISC] October 2021 Forensic Contest: Answers and Analysis, (Thu, Nov 4th)


Thanks to everyone who participated in our October 2021 forensic challenge originally posted on Friday, 2021-10-22.  We received 27 submissions through our contact page, and everyone answered correctly.  Unfortunately, we could only pick one winner.  In this case, our winner was chosen through a random process among the 27 people.  Join us in congratulating this month’s winner, Ameer Mane!  We will contact Ameer, so we can send him a Raspberry Pi 4 kit.

You can still find the material for our October 2021 forensic contest here.

Shown above:  The October 2021 forensic contest pcap opened in Wireshark.


The task was to match each email to the infected Windows host and user.  The answers are:

2021-10-21-malicious-email-1102-UTC.eml – DESKTOP-NZ875R4 – marcus.cobb
2021-10-21-malicious-email-1739-UTC.eml – DESKTOP-CFA3367 – agnes.warren
2021-10-21-malicious-email-2214-UTC.eml – DESKTOP-87WCE26 – kevin.henderson

The environment

As stated in our diary for the October challenge, the three infected Windows hosts are part of an Active Directory (AD) environment, and its characteristics are:

LAN segment range: ( through
Domain: enemywatch.net
Domain Controller: – ENEMYWATCH-DC
LAN segment gateway:
LAN segment broadcast address:

First infection

The first infection started at 14:34:56 UTC, and it happened to the Windows client at  This host generated DNS queries for kamuchehddhgfgf.ddns.net that resolved to  These DNS queries were followed by TCP traffic to over TCP port 1187.

You can find the malicious traffic by using the following Wireshark filter: dns.qry.name contains ddns.net or (ip.addr eq and tcp.flags eq 0x0002)

Shown above:  DNS and TCP traffic from the first infection.

Filtering on Kerberos traffic for reveals hostname DESKTOP-NZ875R4 with Windows user account marcus.cobb.

Shown above:  Kerberos traffic revealing the host name and user account for

The email addressed to [email protected] is 2021-10-21-malicious-email-1102-UTC.eml, which contains a malicious attachment named Order.7z.

Shown above:  Malicious email sent to marcus.cobb.

Sandbox analysis of Order.7z indicates it is NanoCore RAT.  See the links below for details.


Second infection

The second infection started at 14:36:35 UTC, and it happened to  This host generated traffic to sobolpand.top, which is associated with the “Stolen Images campaign” described in this diary from 2021-10-21.  It’s more accurately referred to as a “Contact Forms campaign” which normally pushes BazarLoader malware.

In this case, the Windows host retrieved a DLL from sobolpand.top, and we can extract that DLL from the pcap.

Shown above:  TCP stream of traffic betwen the infected Windows host and sobolpand.top.

Shown above:  Scroll down a little bit in the TCP stream, and you’ll see a DLL file returned by the server.

Shown above:  Extracting the DLL file from the pcap.

The extracted DLL is identified as BazarLoader by this sandbox analysis.

Filtering on Kerberos traffic for reveals hostname DESKTOP-87WCE26 with Windows user account kevin.henderson.

Shown above: Kerberos traffic revealing host name and user account for

The email addressed to [email protected] is 2021-10-21-malicious-email-2214-UTC.eml, which contains a malicious link to a page hosted at firebase.googleapis.com that is no longer active.  When it was active, that URL distributed a malicious zip archive named Critical Errors Report.zip.

Shown above:  Malicious email sent to kevin.henderson.

Note: Unfortunately, when I generated traffic for this exercise, HTTPS activity caused by the host’s request to firebase.googleapis.com was not iincluded in the pcap.

Third infection

The third infection started at 14:37:01 UTC, and it happened to  This host generated HTTP traffic to three URLs ending with /44491/6090605324.dat.  These three URLs returned three DLL files for Qakbot.  The DLL files can be extracted from the pcap, and they all have the same SHA256 hash:


This is a DLL for Qakbot malware as identified by VirusTotal’s sandbox and Tria.ge’s analysis of the binary.  The distribution tag for this Qakbot sample is biden54.

Shown above:  Filtering on web traffic for (and scrolling down a bit).

Indicators of Qakbot post-infection traffic from this infection include:

TCP traffic to over port 65400
HTTPS traffic to www.openssl.org (not inherently malicious)
Several HTTPS requests to api.ipifiy.org (also not inherently malicious)
Encrypted SMTP traffic to several different email servers

Shown above:  Encrypted SMTP traffic to various email servers from

Filtering on Kerberos traffic for reveals hostname DESKTOP-CFA3367 with Windows user account agnes.warren.

Shown above: Shown above:  Kerberos traffic revealing the host name and user account name for

The email addressed to [email protected] is 2021-10-21-malicious-email-1739-UTC.eml, which contains a malicious attachment named Document-1975072354.zip.

Shown above:  Malicious email sent to agnes.warren.

The malicious zip archive contains an Excel spreadsheet with macro code that generated those three URLs ending in /44491/6090605324.dat.

Final words

Our October 2021 forensic contest was relatively easy to answer, but additioinal information about the infections can be found in the pcap.

Congratulations again to Ameer Mane for winning this month’s competition!

You can still find the pcap and emails here.

Brad Duncan
brad [at] malware-traffic-analysis.net

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

Source: Read More (SANS Internet Storm Center, InfoCON: green)

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