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Hunting for C2 Traffic

In this video I look for C2 traffic by doing something I call Rinse-Repeat Threat Hunting, which is a method for removing "normal" traffic in order to look closer at what isn't normal.

The video was recorded in a Windows Sandbox in order to avoid accidentally infecting my Windows PC with malware.

The PCAP files analyzed in the video are:

Thank you for sharing these capture files Brad!

IOC List

  • QBot source: 23.29.125.210
  • QBot md5: 2b55988c0d236edd5ea1a631ccd37b76
  • QBot sha1: 033a22c3bb2b0dd1677973e1ae6280e5466e771c
  • QBot sha256: 2d68755335776e3de28fcd1757b7dcc07688b31c37205ce2324d92c2f419c6f0
  • Qbot proxy protocol server: 23.111.114.52:65400
  • QBot C2: 45.46.53.140:2222
  • QBot C2 JA3: 51c64c77e60f3980eea90869b68c58a8
  • QBot C2 JA3S : 7c02dbae662670040c7af9bd15fb7e2f
  • QBot X.509 domain: thdoot.info
  • QBot X.509 thumbprint: 5a8ee4be30bd5da709385940a1a6e386e66c20b6
  • IcedID BackConnect server: 78.31.67.7:443
  • IcedID BackConnect server: 91.238.50.80:8080

References and Links

Posted by Erik Hjelmvik on Friday, 30 September 2022 12:37:00 (UTC/GMT)

Tags: #Threat Hunting#PCAP#CapLoader#NetworkMiner#NetworkMiner Professional#Video#51c64c77e60f3980eea90869b68c58a8#IcedID

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What is PCAP over IP?

PCAP over IP

PCAP-over-IP is a method for reading a PCAP stream, which contains captured network traffic, through a TCP socket instead of reading the packets from a PCAP file.

A simple way to create a PCAP-over-IP server is to simply read a PCAP file into a netcat listener, like this:

nc -l 57012 < sniffed.pcap

The packets in “sniffed.pcap” can then be read remotely using PCAP-over-IP, for example with tshark like this (replace 192.168.1.2 with the IP of the netcat listener):

nc 192.168.1.2 57012 | tshark -r -

But there’s an even simpler way to read PCAP-over-IP with Wireshark and tshark, which doesn’t require netcat.

wireshark -k -i TCP@192.168.1.2:57012
tshark -i TCP@192.168.1.2:57012

The Wireshark name for this input method is “TCP socket” pipe interface, which is available in Linux, Windows and macOS builds of Wireshark as well as tshark.

Live Remote Sniffing

Sniffed traffic can be read remotely over PCAP-over-IP in real-time simply by forwarding a PCAP stream with captured packets to netcat like this:

tcpdump -U -w - not tcp port 57012 | nc -l 57012
dumpcap -P -f "not tcp port 57012" -w - | nc -l 57012
PCAP-over-IP with tcpdump, netcat and tshark

Tcpdump is not available for Windows, but dumpcap is since it is included with Wireshark.

Note how TCP port 57012 is purposely filtered out using BPF when capturing in order to avoid a snowball effect, where the PCAP-over-IP traffic otherwise gets sniffed and re-transmitted through the PCAP-over-IP stream, which again gets sniffed etc.

Reading PCAP-over-IP with NetworkMiner

We added PCAP-over-IP support to NetworkMiner in 2011 as part of NetworkMiner 1.1, which was actually one year before the TCP socket sniffing feature was included in Wireshark.

Live remote sniffing with NetworkMiner 2.7.3 using PCAP-over-IP

Image: Live remote sniffing with NetworkMiner 2.7.3 using PCAP-over-IP

NetworkMiner can also be configured to listen for incoming PCAP-over-IP connections, in which case the sniffer must connect to the machine running NetworkMiner like this:
tcpdump -U -w - not tcp port 57012 | nc 192.168.1.3 57012

This PCAP-over-IP feature is actually the recommended method for doing real-time analysis of live network traffic when running NetworkMiner in Linux or macOS, because NetworkMiner’s regular sniffing methods are not available on those platforms.

Reading Decrypted TLS Traffic from PolarProxy

PolarProxy

One of the most powerful use-cases for PCAP-over-IP is to read decrypted TLS traffic from PolarProxy. When PolarProxy is launched with the argument “--pcapoverip 57012” it starts a listener on TCP port 57012, which listens for incoming connections and pushes a real-time PCAP stream of decrypted TLS traffic to each client that connects. PolarProxy can also make active outgoing PCAP-over-IP connections to a specific IP address and port if the “--pcapoveripconnect <host>:<port>” argument is provided.

In the video PolarProxy in Windows Sandbox I demonstrate how decrypted TLS traffic can be viewed in NetworkMiner in real-time with help of PCAP-over-IP. PolarProxy’s PCAP-over-IP feature can also be used to read decrypted TLS traffic from PolarProxy with Wireshark as well as to send decrypted TLS traffic from PolarProxy to Arkime (aka Moloch).

Replaying PCAP-over-IP to an Interface

There are lots of great network monitoring products and intrusion detection systems that don’t come with a built-in PCAP-over-IP implementation, such as Suricata, Zeek, Security Onion and Packetbeat, just to mention a few. These products would greatly benefit from having access to the decrypted TLS traffic that PolarProxy can provide. Luckily we can use netcat and tcpreplay to replay packets from a PCAP-over-IP stream to a network interface like this:

nc localhost 57012 | tcpreplay -i eth0 -t -

But for permanent installations we recommend creating a dedicated dummy interface, to which the traffic gets replayed and sniffed, and then deploy a systemd service that performs the replay operation. See our blog post Sniffing Decrypted TLS Traffic with Security Onion for an example on how to deploy such a systemd service. In that blog post we show how decrypted TLS traffic from PolarProxy can be replayed to a local interface on a Security Onion machine, which is being monitored by Suricata and Zeek.

Nils Hanke has also compiled a detailed documentation on how decrypted TLS packets from PolarProxy can be replayed to Packetbeat and Suricata with help of tcpreplay.

In these setups netcat and tcpreplay act as a generic glue between a PCAP-over-IP service and tools that can sniff packets on a network interface, but there are a few drawbacks with this approach. One drawback is that tcpreplay requires root privileges in order to replay packets to an interface. Another drawback is that extra complexity is added to the solution and two additional single point of failures are introduced (i.e. netcat and tcpreplay). Finally, replaying packets to a network interface increases the risk of packet drops. We therefore hope to see built-in PCAP-over-IP implementations in more network monitoring solutions in the future!

FAQ for PCAP-over-IP

Q: Why is it called “PCAP-over-IP” and not “PCAP-over-TCP”?

Good question, we actually don’t know since we didn’t come up with the name. But in theory it would probably be feasible to read a PCAP stream over UDP or SCTP as well.

Q: What is the standard port for PCAP-over-IP?

There is no official port registered with IANA for PCAP-over-IP, but we’ve been using TCP 57012 as the default port for PCAP-over-IP since 2011. The Wireshark implementation, on the other hand, uses TCP port 19000 as the default value.

Q: Which software comes with built-in PCAP-over-IP servers or clients?

The ones we know of are: Arkime, NetworkMiner, PolarProxy, tshark and Wireshark.

Q: Is there some way to encrypt the PCAP-over-IP transmissions?

Yes, we recommend encrypting PCAP-over-IP sessions with TLS when they are transmitted across a non-trusted network. NetworkMiner’s PCAP-over-IP implementation comes with a “Use SSL” checkbox, which can be used to receive “PCAP-over-TLS”. You can replace netcat with socat or ncat in order to establish a TLS encrypted connection to NetworkMiner.

Q: Is there a tool that can aggregate multiple PCAP-over-IP streams into one?

No, none that we’re aware of. However, multiple PCAP-over-IP streams can be merged into one by specifying multiple PCAP-over-IP interfaces in dumpcap and then forwarding that output to a netcat listener, like this:

dumpcap -i TCP@10.1.2.3:57012 -i TCP@10.4.5.6:57012 -w - | editcap -F pcap - - | nc -l 57012

Posted by Erik Hjelmvik on Monday, 15 August 2022 08:05:00 (UTC/GMT)

Tags: #PCAP-over-IP#PCAP#tcpdump#Wireshark#tshark#NetworkMiner#PolarProxy#Suricata#Zeek#Arkime#tcpreplay#netcat#ASCII-art

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CapLoader 1.9.4 Released

CapLoader 1.9.4

A new version of our advanced PCAP filtering tool CapLoader was released today. The new CapLoader 1.9.4 release includes features like JA3 hash extraction from TLS traffic and a fantastic thing called Select Similar Flows, which is a unique feature that you will only find in CapLoader! We have also included a VXLAN parser, so that flows tunneled inside of overlay networks can be presented directly in the CapLoader GUI.

Select Similar Flows or Services

If you right-click a flow or service in CapLoader you’ll now be presented with an option to “select similar flows” (or services). This feature causes CapLoader to read through the loaded PCAP files again in order to find other flows that are similar to the one that was right-clicked. CapLoader doesn’t care about IP addresses or port numbers when assessing this similarity. Instead it looks at behavioral patterns in the traffic itself, such as packet sizes and byte patterns. In practice, this feature will select flows that are communicating using the same protocol as the one you clicked, regardless of which port it runs on. CapLoader already comes with an advanced feature for doing port-independent protocol identification, which currently detects over 170 protocols. But the “select similar” feature can even be used to find odd or proprietary protocols that aren’t in CapLoaders protocol database.

There is also a feature called “select VERY similar flows” which, instead of searching for flows with the same protocol, looks for flows with the same implementation or dialect of that particular protocol. This feature can be used to single out the network traffic of a particular software or tool from a haystack of network traffic from multiple applications, which all run the same application layer protocol. Another use case is to find additional malicious C2 sessions that run on top of a standard protocol like HTTP, TLS or DNS – provided that you’ve located at least one such malicious flow or service.

JA3 and JA3S Hashes for TLS Flows

We added JA3 extraction to NetworkMiner back in 2019, with the release of NetworkMiner 2.5. It’s now time to bring this useful little TLS fingerprinting feature into CapLoader as well. As of version 1.9.4 CapLoader attempts to extract JA3 and JA3S hashes from all TCP flows. The JA3 and JA3S hashes are presented in the Flows and Services tabs as separate columns. This allows users to filter flows based on a JA3 hash directly in CapLoader instead of having to export a filtered PCAP to an external tool to calculate JA3 hashes.

CapLoader with Column Critera filter for JA3 hash

Image: Column criteria filter “JA3 = a72f351cf3c3cd1edb345f7dc071d813” on PCAP from CERT-SE’s 2021 CTF.

Extraction of Flows Inside of VXLAN Tunnels

VXLAN is a network virtualization technology that can be used to create overlay networks, where Ethernet frames are encapsulated inside of UDP packets (see RFC 7348). The UDP port used for VXLAN is 4789 or 8472. We added support for VXLAN to NetworkMiner in 2017, but CapLoader has until now only presented the VXLAN tunnels in the GUI when VXLAN traffic is loaded. We’re happy to announce that CapLoader now extracts flows for the VXLAN tunnels and the traffic inside of those tunnels.

ICMP flow extracted from VXLAN tunnel

Image: ICMP flow extracted from VXLAN tunnel. PCAP file is Virtual_Extensible_LAN-VXLAN.pcap from Xena Networks

Additional GUI Improvements

We’ve also made several minor improvements to CapLoader’s user interface, such as a “Save Visible Flows” option on the File menu, which can be used to save the filtered traffic in the current view to a PCAP file. Another nice addition is the “Copy from Selected Rows” menu option, which can be used to copy text from a particular column.

CapLoader’s OSINT lookup context menus have also been updated to include some very useful services like Feodo Tracker, Hatching Triage and IPVoid.

Free Trial versus Full Version

Many of the new additions to CapLoader are only available in the full version, but the VXLAN extraction and some of the GUI additions are also available in the free trial version of CapLoader. No registration is required to download the trial — just download, extract and run for 30 days. If you like it, then please consider purchasing the full version!

Updating to the Latest Release

Users who have already purchased a license for CapLoader can download a free update to version 1.9.4 from our customer portal.

Posted by Erik Hjelmvik on Thursday, 16 June 2022 11:44:00 (UTC/GMT)

Tags: #CapLoader#JA3#JA3S#Protocol Identification#Protocol Detection#PCAP#TLS#VXLAN

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Real-time PCAP-over-IP in Wireshark

Did you know that it is possible to stream captured packets from a remote device or application to Wireshark in real-time using PCAP-over-IP? This blog post explains how you can configure Wireshark to read decrypted TLS packets directly from PolarProxy over a TCP socket.

PolarProxy

PolarProxy is a TLS proxy that decrypts and re-encrypts TLS traffic, while also saving the decrypted traffic in a PCAP file. Users who wish to inspect the decrypted TLS traffic in Wireshark typically open this file from disk, but that doesn’t allow for a real-time view of the traffic.

PolarProxy comes with a feature called PCAP-over-IP, which provides a real-time PCAP stream with decrypted packets to connecting clients. If you start PolarProxy with “--pcapoverip 57012” then a PCAP-over-IP listener will be set up on TCP port 57012. I have previously demonstrated how this decrypted stream can be read by NetworkMiner, but it was not until recently that I learned that the same thing can be done with Wireshark as well.

PCAP-over-IP in Wireshark

There’s a little known feature in Wireshark that allows a PCAP stream to be read from a TCP socket, which is exactly what PCAP-over-IP is! To connect to a PolarProxy PCAP-over-IP service on the local PC, do as follows:

  1. Capture > Options (or Ctrl+K)
  2. “Manage Interfaces...”
  3. Select the “Pipes” tab
  4. Click the “+” button
  5. Name the pipe “TCP@127.0.0.1:57012” and press ENTER to save it.
    Manage Interfaces in Wireshark
  6. Click “OK” in the Manage Interface window.
  7. Click “Start” to inspect decrypted traffic from PolarProxy in real-time.

This setup works on Windows, Linux and macOS. Just remember to replace 127.0.0.1 with the IP of PolarProxy in case it is running on a remote machine.

Decrypted TLS packets from PolarProxy in Wireshark

Image: Real-time view of HTTP2 packets from decrypted TLS traffic

It’s also possible to read PCAP-over-IP with the command line tool tshark like this:

tshark -i TCP@127.0.0.1:57012

The PCAP-over-IP params can also be supplied to Wireshark on the command line in a similar manner:

wireshark -k -i TCP@127.0.0.1:57012

Happy sniffing!

Posted by Erik Hjelmvik on Tuesday, 24 May 2022 14:00:00 (UTC/GMT)

Tags: #pcapoverip#Wireshark#PolarProxy#PCAP

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Emotet C2 and Spam Traffic Video

This video covers a life cycle of an Emotet infection, including initial infection, command-and-control traffic, and spambot activity sending emails with malicious spreadsheet attachments to infect new victims.

The video was recorded in a Windows Sandbox in order to avoid accidentally infecting my Windows PC with malware.

Initial Infection

Palo Alto's Unit 42 sent out a tweet with screenshots and IOCs from an Emotet infection in early March. A follow-up tweet by Brad Duncan linked to a PCAP file containing network traffic from the infection on Malware-Traffic-Analysis.net.

Screenshot of original infection email from Unit 42

Image: Screenshot of original infection email from Unit 42

  • Attachment MD5: 825e8ea8a9936eb9459344b941df741a

Emotet Download

The PCAP from Malware-Traffic-Analysis.net shows that the Excel spreadsheet attachment caused the download of a DLL file classified as Emotet.

CapLoader download of Emotet DLL from diacrestgroup.com

Image: CapLoader transcript of Emotet download

  • DNS: diacrestgroup.com
  • MD5: 99f59e6f3fa993ba594a3d7077cc884d

Emotet Command-and-Control

Just seconds after the Emotet DLL download completes the victim machine starts communicating with an IP address classified as a botnet command-and-control server.

Emotet C2 sessions with JA3 51c64c77e60f3980eea90869b68c58a8 in CapLoader

Image: Emotet C2 sessions in CapLoader

  • C2 IP: 209.15.236.39
  • C2 IP: 147.139.134.226
  • C2 IP: 134.209.156.68
  • JA3: 51c64c77e60f3980eea90869b68c58a8
  • JA3S: ec74a5c51106f0419184d0dd08fb05bc
  • JA3S: fd4bc6cea4877646ccd62f0792ec0b62

Emotet Spambot

The victim PC eventually started sending out spam emails. The spam bot used TLS encryption when possible, either through SMTPS (implicit TLS) or with help of STARTTLS (explicit TLS).

Emotet spambot JA3 hash 37cdab6ff1bd1c195bacb776c5213bf2 in NetworkMiner Professional

Image: Emotet spambot JA3 hash in NetworkMiner Professional

  • SMTPS JA3: 37cdab6ff1bd1c195bacb776c5213bf2
  • STARTTLS JA3: 37cdab6ff1bd1c195bacb776c5213bf2

Transmitted Spam

Below is a spam email sent from the victim PC without TLS encryption. The attached zip file contains a malicious Excel spreadsheet, which is designed to infect new victims with Emotet.

Emotet spam email from PCAP

Image: Spam email extracted from Emotet PCAP with NetworkMiner

  • .zip Attachment MD5: 5df1c719f5458035f6be2a071ea831db
  • .xlsm Attachment MD5: 79cb3df6c0b7ed6431db76f990c68b5b

Network Forensics Training

If you want to learn additional techniques for analyzing network traffic, then take a look at our upcoming network forensic trainings.

Posted by Erik Hjelmvik on Monday, 09 May 2022 06:50:00 (UTC/GMT)

Tags: #Emotet#C2#video#pcap#JA3#JA3S#51c64c77e60f3980eea90869b68c58a8#SMTP#SMTPS#Windows Sandbox

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Industroyer2 IEC-104 Analysis

The Industroyer2 malware was hardwired to attack a specific set of electric utility substations in Ukraine. It seems to have been custom built to open circuit breakers, which would effectively cut the power from the substation.

Industroyer2

After connecting to an RTU in a substation the malware would immediately start changing the outputs at specific addresses without first having to enumerate which IOAs that were available on the targeted device. This custom-built malware seems to know what IOAs to use at each station, as well as what type of output each specific IOA controls.

UPDATE 2022-04-26

Upon popular demand we've decided to release three PCAP files with IEC-104 traffic from our own sandbox execution of the Industroyer2 malware. Please feel free to use these capture files to verify our findings using any tool of your choice. The capture files can be downloaded from here:
https://www.netresec.com/files/Industroyer2-Netresec.zip

These PCAP files are shared under a CC BY 4.0 license, which allows you to redistribute them as long as you give appropriate credit.

UPDATE 2022-04-29

A PNG image in the original CERT-UA security alert #4435 turned out to actually include the IOAs targeted by the non-public 108_100.exe Industroyer2 version. The IOAs disclosed in CERT-UAs alert have now been included in this blog post as well.

Backstory

I was looking at a public sandbox execution of a presumed Industroyer2 malware sample two weeks ago. At first glance the malware sample, which was named “40_115.exe”, didn't do much. It just printed the text below to the console and then terminated the process.

19:46:06:0106> T281 00006800
19:46:06:0247> RNM 0015
19:46:06:0294> 10.82.40.105: 2404: 3
19:46:06:0294> T65 00006800
19:46:06:0341> 10.82.40.105 M68B0 SGCNT 44
19:46:06:0497> RNM 0015
19:46:06:0544> T113 00006800
19:46:06:0544> 192.168.122.2: 2404: 2
19:46:06:0544> 192.168.122.2 M68B0 SGCNT 8
19:46:06:0591> RNM 0015
19:46:06:0653> 192.168.121.2: 2404: 1
19:46:06:0700> 192.168.121.2 M68B0 SGCNT 16
19:46:21:0747> 192.168.122.2 M6812
19:46:21:0747> 10.82.40.105 M6812
19:46:21:0794> 192.168.121.2 M6812

I later noticed that it also sent TCP SYN packets to three different RFC1918 addresses, but never received a response.

Industroyer2 trying to connect to TCP port 2404 on 10.82.40.105, 192.168.122.2 and 192.168.121.2 in Wireshark

Image: Wireshark showing Industroyer2 trying to reach TCP port 2404

TCP port 2404 is used by the SCADA protocol IEC 60870-5-104, also known as IEC-104, which is primarily used to monitor and control electricity transmission and distribution systems. IEC-104 is also the only Industrial Control System (ICS) protocol implemented in Industroyer2 according to ESET. The previous version of Industroyer, which was used to cut the power in Ukraine in 2016, additionally supported the IEC 61850 and OPC DA protocols according to the CRASHOVERRIDE report from Dragos.

Industroyer2's IEC-104 client didn't receive any SYN+ACK response in the sandbox execution I was looking at, so I couldn't tell what it was trying to do. I therefore decided to set up my own sandbox with a built-in IEC-104 server (also known as a slave, RTU or IED). My sandbox execution confirmed that Industroyer2 was indeed trying to communicate with these three IP addresses using IEC-104. I also noticed that it was very specific about which outputs (or IOAs) it wanted to access on those servers in order to turn these outputs either ON or OFF.

Station Address 1 at 192.168.121.2

The Industroyer2 malware spawned three separate threads when started, one thread for each IEC-104 server to contact. The malware would communicate with all three servers in parallel if all of them were available. However, in order to simplify my analysis I decided to only respond to one of the IPs at a time, starting with IP address 192.168.121.2.

The thread that connected to IP address 192.168.121.2 toggled all outputs between 1250 and 1265 to OFF at Station Address 1 (also known as “ASDU address” or “common address”). Judging from the command type used (ID 46 with short pulse duration) these outputs likely control circuit breakers, which are used to disconnect the power from an electric utility substation.

IEC-104 traffic to 192.168.121.2 in NetworkMiner

Image: PCAP file with IEC-104 traffic to 192.168.121.2 in NetworkMiner

Station Address 2 at 192.168.122.2

On 192.168.122.2 the malware targeted station address 2, where it toggled outputs between 1101 and 1108 to OFF.

IEC-104 traffic to 192.168.122.2 in NetworkMiner

Image: PCAP file with IEC-104 traffic to 192.168.122.2 in NetworkMiner

Station Address 3 at 10.82.40.105

The malware toggled a great deal of outputs on 10.82.40.105, which had station address 3. But in contrast to the other stations, many of these outputs were toggled to the “ON” state rather than “OFF”.

IEC-104 traffic to 10.82.40.105 in NetworkMiner

Image: PCAP file with IEC-104 traffic to 10.82.40.105 in NetworkMiner

Yet, after setting those outputs to “ON” it proceeded with setting outputs to “OFF” for several other IOAs on station address 3.

IEC-104 traffic to 10.82.40.105 in NetworkMiner

Image: PCAP file with IEC-104 traffic to 10.82.40.105 in NetworkMiner

In each thread Industroyer2 paused for approximately 3 seconds between each accessed IOA. This delay seems to have been hard coded since the malware didn't seem to care whether or not the IEC-104 server responded with an OK message, such as ACT or ACTTERM, or an error message, like “unknown common address of ASDU”. Each thread would simply proceed with setting an IOA every 3 seconds no matter what the server responded.

The specific order in which the IOAs were accessed was also very deterministic, the exact same sequence of IOAs was used every time. I verified this behavior by running the malware multiple times as well as by comparing my results to an execution of the same sample on a different sandbox (thanks for the PCAP Joe and Dan).

What Did the Attackers Know?

The fact that the malware toggled these specific outputs, rather than just randomly turning outputs ON or OFF, indicates that the threat actors had technical knowledge about the specific substation(s) they were attacking. Not only did the attackers know the IP addresses, station addresses and IOAs of each targeted output. They also knew what ASDU Type ID to use for each respective output. For IOA 1101 to 1404 the Type ID 46 was used (also known as "double command" or C_DC_NA_1) while for IOAs from 130202 and above it used Type ID 45 (also known as “single command” or C_SC_NA_1).

As you can see in the previous screenshots, NetworkMiner nicely parses and presents the IEC-104 commands issued by Industroyer2. But I noticed that the malware also printed all sent and received commands to the console when executed. For example, the following output was printed to the console by the Industroyer2 thread communicating with station address 2 on 192.168.122.2:

11:51:56:0163> T65 00006800
11:51:56:0201> RNM 0003
11:51:56:0241> 192.168.122.2: 2404: 2
11:51:56:0267> 192.168.122.2 M68B0 SGCNT 8
11:51:56:0297> 192.168.122.2 M6813

The string “192.168.122.2: 2404: 2” above reveals that “2404” is the target port and “2” is the station address. The “SGCNT 8” string additionally tells us that there were 8 outputs to be toggled on that station. The other two stations had SGCNT 16 and 44.

The malware also printed very detailed information about each sent and received IEC-104 command, such as in the example below where the output at IOA 1104 was successfully turned off at station address 2 (here referred to as “ASDU:2”).

MSTR ->> SLV 192.168.122.2:2404
  x68 x0E x02 x00 x08 x00 x2E x01 x06 x00 x02 x00 x50 x04 x00 x05

  I |Length:16 bytes | Sent=x1 | Received=x4
  ASDU:2 | OA:0 | IOA:1104 |
  Cause: (x6) | Telegram type: (x2E)

MSTR <<- SLV 192.168.122.2:2404
  x68 x0E x08 x00 x04 x00 x2E x01 x47 x00 x02 x00 x50 x04 x00 x05

  I |Length:16 bytes | Sent=x4 | Received=x2
  ASDU:2 | OA:0 | IOA:1104 |
  Cause: (x47) | Telegram type: (x2E)

Note that the Type ID values were also logged to the console by Industroyer2, but it used the term “Telegram type” instead of “Type ID”.

Static Analysis

The following three Unicode strings can be found in the 40_115.exe binary:

10.82.40.105 2404 3 0 1 1 PService_PPD.exe 1 "D:\OIK\DevCounter" 0 1 0 0 1 0 0 44 130202 1 0 1 1 1 160921 1 0 1 1 2 160923 1 0 1 1 3 160924 1 0 1 1 4 160925 1 0 1 1 5 160927 1 0 1 1 6 160928 1 0 1 1 7 190202 1 0 1 1 8 260202 1 0 1 1 9 260901 1 0 1 1 10 260902 1 0 1 1 11 260903 1 0 1 1 12 260904 1 0 1 1 13 260905 1 0 1 1 14 260906 1 0 1 1 15 260907 1 0 1 1 16 260908 1 0 1 1 17 260909 1 0 1 1 18 260910 1 0 1 1 19 260911 1 0 1 1 20 260912 1 0 1 1 21 260914 1 0 1 1 22 260915 1 0 1 1 23 260916 1 0 1 1 24 260918 1 0 1 1 25 260920 1 0 1 1 26 290202 1 0 1 1 27 338501 1 0 1 1 28 1401 0 0 0 1 29 1402 0 0 0 1 30 1403 0 0 0 1 31 1404 0 0 0 1 32 1301 0 0 0 1 33 1302 0 0 0 1 34 1303 0 0 0 1 35 1304 0 0 0 1 36 1201 0 0 0 1 37 1202 0 0 0 1 38 1203 0 0 0 1 39 1204 0 0 0 1 40 1101 0 0 0 1 41 1102 0 0 0 1 42 1103 0 0 0 1 43 1104 0 0 0 1 44
192.168.122.2 2404 2 0 1 1 PService_PPD.exe 1 "D:\OIK\DevCounter" 0 1 0 0 1 0 0 8 1104 0 0 0 1 1 1105 0 0 0 1 2 1106 0 0 0 1 3 1107 0 0 0 1 4 1108 0 0 0 1 5 1101 0 0 0 1 6 1102 0 0 0 1 7 1103 0 0 0 1 8
192.168.121.2 2404 1 0 1 1 PService_PPD.exe 1 "D:\OIK\DevCounter" 0 1 0 0 1 0 0 16 1258 0 0 0 1 1 1259 0 0 0 1 2 1260 0 0 0 1 3 1261 0 0 0 1 4 1262 0 0 0 1 5 1265 0 0 0 1 6 1252 0 0 0 1 7 1253 0 0 0 1 8 1254 0 0 0 1 9 1255 0 0 0 1 10 1256 0 0 0 1 11 1257 0 0 0 1 12 1263 0 0 0 1 13 1264 0 0 0 1 14 1250 0 0 0 1 15 1251 0 0 0 1 16

After having analyzed the IEC-104 traffic from the binary it's obvious that this is the IEC-104 configuration that has been hard-coded into the binary. For example, the substring “10.82.40.105 2404 3” in the first Unicode string refers to the IP, port and station number of the first target.

The “16 1258 [...]” section in the third Unicode string above tells us that there are 16 outputs configured for station address 1, where the first one to be set is at IOA 1258. Thus, we can easily verify that all accessed IOAs on all three stations were hard-coded into the binary.

Additional Substations Targeted

The malware sample I've analyzed has the following properties:

  • Filename: 40_115.exe
  • MD5: 7c05da2e4612fca213430b6c93e76b06
  • SHA1: fdeb96bc3d4ab32ef826e7e53f4fe1c72e580379
  • SHA256: d69665f56ddef7ad4e71971f06432e59f1510a7194386e5f0e8926aea7b88e00
  • Compiled: 2022-03-23 10:07:29 UTC

But there is an additional Industroyer2 sample called “108_100.exe” (MD5 3229e8c4150b5e43f836643ec9428865), which has been mentioned by ESET as well as CERT-UA. I haven't been able to access that binary though, so I don't yet know which IP addresses it was designed to target. However, a few screenshots [1] [2] [3] published by ESET reveal that the 108_100.exe malware sample was hard coded to access 8 different station addresses, 5 of which were on the 10.0.0.0/8 network and 3 on the 192.168.0.0/16 net. An image in CERT-UA's alert #4435 from April 12 reveals the targeted IOAs for these 8 stations.

Targets hard-coded in 108_100.exe ordered by station address:

  • SA#1, 192.x.x.x, 12 IOAs (1101-1104, 1201-1204, 1301-1304)
  • SA#2, 10.x.x.x, 12 IOAs (1101-1104, 1201-1204, 1301-1304)
  • SA#3, 192.x.x.x, 18 IOAs (1103-1104, 1201-1204, 1301-?, 38601-38607)
  • SA#4, 10.x.x.x, 34 IOAs (16501, 16603, 26502, 38507-38513, 38519-38524 and more...)
  • SA#5, 192.x.x.x, 10 IOAs (1101-1103, 1201-1204, 1301-1303)
  • SA#6, 10.x.x.x, 8 IOAs (1101-1104, 1201-1204)
  • SA#7, 10.x.x.x, 8 IOAs (1101-1104, 1201-1204)
  • SA#8, 10.x.x.x, 8 IOAs (1101-1104, 1201-1204)

We can compare those station addresses, IP addresses and IOAs to the ones targeted by the 40_115.exe sample, which was analyzed in this blog post.

  • SA#1, 192.168.121.2, 16 IOAs (1250-1265)
  • SA#2, 192.168.122.2, 8 IOAs (1101-1108)
  • SA#3, 10.82.40.105, 44 IOAs (1101-1104, 1201-1204, 1301-1304, 1401-1404, 130202, 160921-160928, 190202, 260202, 260901-260920, 290202, 338501)

There doesn't seem to be any overlap across the two sets (except for possibly station address 1 which is on the 192.x.x.x network in both configs but has different IOAs). This indicates that the 108_100.exe Industroyer2 version was hard coded to attack a different set of targets than the 40_115.exe sample that I've analyzed.

More ICS blog posts from Netresec

If you'd like to find our earlier work in the field of ICS/SCADA security, then check out these (slightly older but still very relevant) blog posts:

Posted by Erik Hjelmvik on Monday, 25 April 2022 10:35:00 (UTC/GMT)

Tags: #IEC-104#60870-5-104#ICS#ICS#SCADA#PCAP

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NetworkMiner 2.7.3 Released

NetworkMiner 2.7.3

NetworkMiner now extracts meterpreter payloads from reverse shells and performs offline lookups of JA3 hashes and TLS certificates. Our commercial tool, NetworkMiner Professional, additionally comes with a packet carver that extracts network packets from memory dumps.

Extraction of Meterpreter Payloads

NetworkMiner 2.7.3 supports extraction of meterpreter DLL payloads from reverse shell TCP sessions deployed with Metasploit. The free version of NetworkMiner will try to extract the meterpreter DLL from TCP sessions going to "poker-hand ports" commonly used for meterpreter sessions, such as 3333, 4444, 5555, etc. The port-independent protocol detection feature available in NetworkMiner Professional additionally enables extraction of meterpreter DLLs regardless which LPORT the attacker specifies when deploying the reverse shell.

Meterpreter DLL extracted from PCAP file in NetworkMiner Professional

Image: Meterpreter DLL extracted from DFIR Madness' case001.pcap

Packet Carving in NetworkMiner Professional

If you try to open anything other than a PCAP, PcapNG or ETL file in NetworkMiner Professional, then you'll be presented with an option to carve packets from the opened file as of this release.

NetworkMiner Unknown Capture File Format

The packet carver can extract packets from any structured or unstructured data, such as memory dumps and proprietary packet capture formats. NetworkMiner Pro's carver is a simplified version of the packet carving feature in CapLoader.

Loading the 1GB "memdump.mem" from Ali Hadi's Challenge #1 - Web Server Case into NetworkMiner Professional takes roughly five seconds, during which 612 packets get extracted.

NetworkMiner Professional with packets extracted from memory dump

Image: Information about network hosts carved from memory dump

In this scenario the memory was dumped on the 192.168.56.101 host, which NetworkMiner identifies as "WIN-L0ZZQ76PMUF". The carved packets also indicate that this computer had an outgoing TCP connection to 192.168.56.102, which appears to be a Linux machine called "kali". As you can see in the screenshot, the packets carved from the memory dump also reveal a great deal about other hosts on the network, such as the 192.168.56.1 host, which seems to be a Windows 7 machine called "IT104-00".

Offline Matching of JA3 and X.509 hashes

NetworkMiner 2.7.3 comes with a local copy of the SSL Certificate and JA3 Fingerprint Blacklists from the awesome abuse.ch project. JA3 hashes and extracted X.509 certificates are matched against these lists in order to see if they are associated with any piece of malware or botnet.

Here's one example showing the default Cobalt Strike certificate being identified as "AKBuilder C&C", since that's how it is listed in abuse.ch's SSL certificate database.

CobaltStrike default X.509 certificate

Image: Cobalt Strike's default certificate identified as "AKBuilder C&C"
PCAP: Cobalt Strike PCAP from malware-traffic-analysis.net

The port-independent protocol detection feature in NetworkMiner Professional additionally enables X.509 certificates to be extracted even from non-standard TLS ports, such as this certificate, which is identified as "BitRAT" with help of the abuse.ch certificate block-list.

NetworkMiner Professional with BitRAT TLS traffic

Image: Both X.509 certificate and JA3 hash identified as BitRAT
PCAP: BitRAT PCAP from Joe Sandbox

The client's JA3 hash 8515076cbbca9dce33151b798f782456 is also associated with BitRAT according to abuse.ch.

DBSBL Lookup Detection

DNSBL services are used by servers handling incoming email to verify that the sender's IP address isn't a known SPAM sender and that it isn't from a network that shouldn't be sending emails.

But DNSBL services can also be used by malware and botnets, such as TrickBot and Emotet, to verify that the public IP of a victim is allowed to send emails and that it hasn't already been blacklisted for sending SPAM. We have therefore decided to add DNSBL lookups to the Host Details section in NetworkMiner 2.7.3.

DNSBL lookups in NetworkMiner

Image: TrickBot victim checks if its public IP is blocked by DNSBL services
PCAP: TrickBot PCAP from malware-traffic-analysis.net

DNSBL lookups are also logged to the "Parameters" tab of NetworkMiner.

NetworkMiner with DNSBL parameters

Image: NetworkMiner's Parameters tab with "DNSBL" filter
PCAP: TrickBot PCAP from malware-traffic-analysis.net

Additional Features and Updates

We'd also like to mention some additional new features, bug fixes and improvements that have been included in this new release.

  • Support for HTTP CONNECT request method to extract artifacts like X.509 certificates and JA3 hashes from HTTPS traffic passing through a web proxy.
  • Traffic to TCP ports 3000 and 8000 are now configured to be parsed as HTTP by default in order to handle WEBrick traffic.
  • Improved extraction of SMTP credentials.
  • JA3 hashes were previously incorrect for clients that supported more than one EC point format (RFC 8422). This has now been fixed.
  • Support for SLL2 (Linux cooked capture v2) frames.
  • Improved handling of concurrent GUI events, for example when poking around in the "Hosts" tab while loading a PCAP file or doing live sniffing.
  • NetworkMiner's GUI no longer reloads between each PCAP file when multiple files are loaded at once.

New Features in NetworkMiner Professional

We have also added a few new features exclusively to NetworkMiner Professional, which is the commercial version of NetworkMiner. Apart from the packet carver feature, mentioned earlier in this blog post, we've also updated the collection of OSINT lookup services available in the GUI. One of the newly added services is Ryan Benson's unfurl, which picks apart URLs to reveal data that might have been encoded into a complex URL. The unfurl lookup can be found by right-clicking an URL in NetworkMiner Professional's "Browsers" tab and selecting the "Lookup URL" sub menu.

Other OSINT services that we've added are FileScan.IO and JoeSandbox lookups of extracted files. These lookups can be performed by right clicking a file in the "Files" tab and opening the sub-menu called "Lookup Hash".

Lookup of file hash on JoeSandbox

Image: OSINT lookup of an EXE file extracted from network traffic

The command-line version of NetworkMiner Professional, NetworkMinerCLI, has also been updated to allow extracted information to be printed directly on standard output instead of logging everything to files. Here is an example showing this feature while running NetworkMinerCLI in Linux (with help of Mono):

mono /opt/NetworkMinerProfessional_2-7-3/NetworkMinerCLI.exe -r 2022-03-14-Qakbot-with-Cobalt-Strike-and-VNC-module.pcap -w /tmp/malware -X FileInfos | cut -d, -f 5,9
"s2Fmok83x.zip.html","ba2ef33c7aef593f95d261b6f4406b39"
"nexus.officeapps.live.com.cer","373ccffe30d3477867642abab723a351"
"Microsoft RSA TLS CA 01.cer","806f1c72f6d67c9c114eff43d3d84100"
"nexusrules.officeapps.live.c.cer","4c08442740cb020d457a5df16be406ff"
"Microsoft RSA TLS CA 02.cer","65d17ecae5798c79db8e840fe98a53b9"
"6537991.dat.exe","124207bc9c64e20e114bcaeabde12a4e"
"6537991.dat.exe","ca7ef367c935182a40a95b9ad8b95f42"
"6537991.dat.exe","a9a8366fa6be54b45ca04192ca217b75"
[...]

The command above extracts files from a PCAP file, which contains traffic from a Windows PC infected with Qbot. The "-w" switch specifies the output directory for the files extracted from network traffic, and the "-X FileInfos" specifies that metadata for these files should be sent to STDOUT instead of being written to log files. The cut utility was used to show only the filename (column 5) and MD5 hash (column 9) of the file info output.

The MD5 hashes of the extracted files confirm that this is indeed a Qbot infection:

  • 124207bc9c64e20e114bcaeabde12a4e (VT)
  • ca7ef367c935182a40a95b9ad8b95f42 (VT)
  • a9a8366fa6be54b45ca04192ca217b75 (VT)

NetworkMinerCLI previously printed some information about the parsing process to STDOUT. That output has now been moved to STDERR in order to provide the "-X [type]" output with exclusive access to STDOUT.

Credits

We'd like to thank Michael Taggart for noticing that NetworkMiner previously failed to parse HTTP traffic to ports 3000 and 8000.

Upgrading to Version 2.7.3

Users who have purchased NetworkMiner Professional can download a free update to version 2.7.3 from our customer portal, or use the “Help > Check for Updates” feature. Those who instead prefer to use the free and open source version can grab the latest version of NetworkMiner from the official NetworkMiner page.

Posted by Erik Hjelmvik on Monday, 04 April 2022 06:52:00 (UTC/GMT)

Tags: #NetworkMiner#carve#JA3#X.509#CobaltStrike#Cobalt Strike#TrickBot#Emotet#PIPI#Protocol Detection#OSINT#NetworkMinerCLI

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