FOR572: Advanced Network Forensics and Analysis
Take your system-based forensic knowledge onto the wire. Incorporate network evidence into your investigations, provide better findings, and get the job done faster.
Forensic casework that does not include a network component is a rarity in today's environment. Performing disk forensics will always be a critical and foundational skill for this career, but overlooking the network component of today's computing architecture is akin to ignoring security camera footage of a crime as it was committed. Whether you handle an intrusion incident, data theft case, or employee misuse scenario, the network often has an unparalleled view of the incident. Its evidence can provide the proof necessary to show intent, or even definitively prove that a crime actually occurred.
FOR572: ADVANCED NETWORK FORENSICS AND ANALYSIS was built from the ground up to cover the most critical skills needed to mount efficient and effective post-incident response investigations. We focus on the knowledge necessary to expand the forensic mindset from residual data on the storage media from a system or device to the transient communications that occurred in the past or continue to occur. Even if the most skilled remote attacker compromised a system with an undetectable exploit, the system still has to communicate over the network. Without command-and-control and data extraction channels, the value of a compromised computer system drops to almost zero. Put another way: Bad guys are talking - we will teach you to listen.
This course covers the tools, technology and processes required to integrate network evidence sources into your investigations, with a focus on efficiency and effectiveness. You will leave this week with a well-stocked toolbox and the knowledge to use it on your first day back on the job. We will cover the full spectrum of network evidence, including high-level NetFlow analysis, low-level pcap exploration, ancillary network log examination, and more. We cover how to leverage existing infrastructure devices that may contain months or years of valuable evidence as well as how to place new collection platforms while an incident is already under way.
Whether you are a consultant responding to a client's site, a law enforcement professional assisting victims of cybercrime and seeking prosecution of those responsible, or an on-staff forensic practitioner, this course offers hands-on experience with real-world scenarios that will help take your work to the next level. Previous SANS SEC curriculum students and other network defenders will benefit from the FOR572 perspective on security operations as they take on more incident response and investigative responsibilities. SANS Forensic alumni from 408 and 508 can take their existing knowledge and apply it directly to the network-based attacks that occur daily. In FOR572, we solve the same caliber of real-world problems without any convenient hard drive or memory images.
The hands-on exercises in this class cover a wide range of tools, including the venerable tcpdump and Wireshark for packet capture and analysis; commercial tools from NetWitness and NetworkMiner; and open-source tools including nfdump, tcpxtract, Logstash, and more. Through all of these exercises, your shell scripting abilities will come in handy to make easy work of ripping through hundreds and thousands of data records.
FOR572 is truly an advanced course - we hit the ground running on day one. Bring your entire bag of skills: forensic techniques and methodologies, networking (from the wire all the way up to user-facing services), Linux shell utilities, and everything in between. They will all benefit you throughout the course material as you
BAD GUYS ARE TALKING - WE WILL TEACH YOU TO LISTEN.
Foundational network forensics tools: tcpdump and Wireshark refresher
Packet capture applications and data
Considerations between disk-based and network-based forensics
- Fundamentals of managing investigative hypotheses
- Network evidence sources and types
- Case management and evidence collection/handling
- Network architectural challenges and opportunities for investigators
- Investigation OPSEC and footprint considerations
Network protocol analysis
- Dynamic Host Configuration Protocol and Domain Name Service
- Hypertext Transfer Protocol
- Secure HTTP/Secure Sockets Layer
- File Transfer Protocol
- Network Time Protocol
- Microsoft protocols
- Simple Mail Transfer Protocol
Commercial network forensics
Automated tools and libraries
- Collection approaches
- Open-source NetFlow tools
- Commercial tool suites
Visualization tools and techniques
- Capturing wireless traffic
- Identifying clients susceptible to fake access-point-based MITM attacks
- Detecting fake access points and the client(s) they attacked
Log data to supplement network examinations
- Microsoft eventing
- HTTP server logs
- Firewall and IDS
- Log collection, aggregation, and analysis
- Web proxy server examination
- Encrypted traffic flow analysis
Deep packet work
- Network protocol reverse engineering
- Payload reconstruction
|FOR572.1: Off the Disk and onto the Wire|
Focus: Although many concepts of network forensics are similar to those of any other digital forensic investigation, the network presents many nuances that require special attention. Today you will learn how to apply what you already know about digital forensics and incident response to network-based evidence. You will also become acclimated to the basic tools of the trade.
Network data can be preserved, but only if captured directly from the wire. Whether tactical or strategic, packet capture methods are quite basic. You will re-acquaint yourself with tcpdump and Wireshark, the most common tools used to capture and analyze network packets, respectively. However, since long-term full-packet capture is still uncommon in most environments, many artifacts that can tell us about what happened on the wire in the past come from devices that manage network functions. You will learn about what kinds of devices can provide valuable evidence and at what level of granularity. We will walk through collecting evidence from one of the most common sources of network evidence - a web proxy server - then go hands-on to find and extract stolen data from the proxy yourself.
The Linux SIFT virtual machine, which has been specifically loaded with a set of network forensic tools, will be your primary toolkit for the week.
CPE/CMU Credits: 6
Goals of Forensic Investigation
Hypothesis Management Fundamentals
Foundational Network Forensics Tools: tcpdump and Wireshark
Network Evidence Sources and Types
Case Management and Evidence Collection/Handling
Web Proxy Server Examination
Network Architectural Challenges and Opportunities
Packet Capture Applications and Data
|FOR572.2: Network Protocols and Commercial Network Forensics|
Focus: Network protocols are the foundation on which all network communications build. Without an understanding of how the most fundamental protocols behave, further examination and investigation is simply impossible. More importantly, without honing the skills necessary to learn new protocols, the network forensicator will be unprepared for the future in the rapidly evolving field in which we work.
This section covers some of the most common and fundamental network protocols that you will likely face during an investigation. We will cover a broad range of protocols including the Dynamic Host Configuration Protocol, which "glues" together layers two and three on the OSI model, and Microsoft's Remote Procedure Call protocol, which provides all manners of file, print, name resolution, authentication, and other services.
While no one course could ever exhaustively cover the dizzying list of protocols used in a typical network environment, you will build the skills needed to learn whatever new protocols may come your way. The "learn how to learn" skill is critical, as new protocols are being developed every day. Advanced adversaries develop their own protocols, too, and as you will see later in this class, successfully understanding and counteracting an adversary's undocumented protocol is a similar process to learning those you will see in this section.
You will also take this new protocol knowledge "hands on" in real-world scenarios.
CPE/CMU Credits: 6
Dynamic Host Configuration Protocol (DHCP) and Domain Name Service (DNS)
Hypertext Transfer Protocol (HTTP)
Secure HTTP (HTTPS) and Secure Sockets Layer (SSL)
File Transfer Protocol (FTP)
Network Time Protocol (NTP)
Commercial Network Forensics
Simple Mail Transfer Protocol (SMTP)
|FOR572.3: Netflow Analysis and Wireless Network Forensics|
FOCUS: Network connection logging, commonly called NetFlow, may be the single most valuable source of evidence in network investigations. Many organizations have extensive archives of flow data due to its minimal storage requirements. Since NetFlow does not capture any content of the transmission, many legal issues with long-term retention are mitigated. Even without content, NetFlow provides an excellent means of guiding an investigation and characterizing an adversary's activities from pre-attack through operations.
Just as photos from high-altitude reconnaissance aircraft and satellites are instrumental in national policy decisions, NetFlow data can provide a network investigator with extremely high-value intelligence about network communications. The key to extracting that value is in knowing how to use NetFlow evidence to drive more detailed (and labor-intensive) investigative activities.
In this section, you will learn what data items NetFlow can provide, and the various means of collecting those items. As with many such monitoring technologies, both commercial and open-source solutions exist to query and examine NetFlow data. We will review both categories and discuss the benefits and drawbacks of each.
In the same vein, presenting concise findings from extremely large data sources is an important skill. A network forensicator should be able to aggregate and visually present findings, especially when faced with a years-long compromise incident. Expressing findings supported with visualizations can provide a much clearer picture than words alone.
Finally, we will address the forensic aspects of wireless networking. We will cover similarities with and differences from traditional wired network examination, as well as what interesting artifacts can be recovered from wireless protocol fields. Some inherent weaknesses of wireless deployments will also be covered, including how attackers can leverage those weaknesses during an attack, and how they can be detected.
CPE/CMU Credits: 6
Introduction to NetFlow
NetFlow Collection Approaches
Open-Source Flow Tools
Commercial Flow Analysis Suites
Visualization Techniques and Tools
Wireless Network Forensics
|FOR572.4: Logging, OPSEC, and Footprint|
Focus: Full-packet capture evidence is often unavailable. Even when it is, the period of coverage rarely extends past a few weeks. Incidents frequently go undiscovered for months or years, so we must turn to what evidence does exist to characterize the network activity around the time of original compromise. Existing infrastructure assets can also be reconfigured to gather more or higher fidelity evidence during an incident response.
Log data is one of the unsung heroes in the realm of network forensics. While the near-perfect knowledge that comes with full-packet capture seems ideal, it suffers from several shortfalls. It is often unavailable, as many organizations have not yet deployed or cannot deploy comprehensive collection systems. When they are in use, network capture systems quickly amass a huge volume of data, which is often difficult to process effectively and must be maintained in a rolling buffer covering just a few days or weeks.
Understanding log data and how it can guide the investigative process is an important network forensicator skill. Examining network-centric logs can also fill gaps left by an incomplete or nonexistent network capture.
In this section, you will learn various logging mechanisms available to both endpoint and network transport devices. You will also learn how to consolidate log data from multiple sources, providing a broad corpus of evidence in one location. As the volume of log data increases, so does the need to consider automated analytic tools. You will learn various solutions that accomplish this, from tactical to enterprise-scale.
Another benefit available in the network domain of incident response is the ability to repurpose infrastructure devices so they will better serve an ongoing investigation. When properly executed, this practice becomes an invaluable component in the incident response cycle. As incident responders acquire intelligence, they tune collections to better track the adversary's actions, which then begets better intelligence. This process requires special care, however, since interaction with active devices can create additional network traffic, and therefore, additional source evidence. As in many forensic processes, the key is to take measured steps, make minimal changes, and keep detailed documentation of each step.
Finally, the network domain provides some significantly different challenges than the traditional computer forensic domain. The process of analysis and research is an active one - simply looking up a domain name from a log file can alert an attacker to the response team's status in the investigation. You will learn which types of activities should be avoided and which can be mitigated to better ensure operational security.
CPE/CMU Credits: 6
HTTP Server Logs
Firewall and Intrusion Detection Systems
Log Data Collection, Aggregation, and Analysis
Investigation OPSEC and Footprint Considerations
|FOR572.5: Encryption, Protocol Reversing, and Automation|
Focus: Advancements in common technology have made it easier to be a bad guy and harder for us to track them. Sound encryption methods are readily available and custom protocols are easy to develop and employ. Despite this, there are still weaknesses even in the most advanced adversaries' methods.
Encryption is frequently cited as the most significant hurdle to effective network forensics - and for good reason. When properly implemented, encryption can be a brick wall in between an investigator and critical answers. However, technical and implementation weaknesses can be used to our advantage. Even in the absence of these weaknesses, the right analytic approach to encrypted network traffic can still yield valuable information about the content. We will discuss the basics of encryption and how to approach it during an investigation. The section will also cover flow analysis to characterize encrypted conversations.
In addition, this section addresses how network forensicators can rebuild fragmented payloads in order to reconstruct original communication streams. We will then address undocumented protocols and how to derive intelligence value with limited or nonexistent knowledge of the protocol.
Finally, we will discuss how to pivot labor-intensive tasks into scalable solutions through automation. Whether chaining single-use tools together to create an end-to-end solution or developing a new tool using various existing forensically minded libraries, your methods can be applied as easily to terabytes of live-source data as they can to a 2-gigabyte pcap.
CPE/CMU Credits: 6
Introduction to Encryption
Encrypted Traffic Flow Analysis
Network Protocol Reverse Engineering
Automated Tools and Libraries
|FOR572.6: Network Forensics Capstone Challenge|
Focus: This section will combine all of what you have learned prior to and during this week. In groups, you will examine network evidence from a real-world compromise by an advanced attacker. Each group will independently analyze data, form and develop hypotheses, and present findings. No evidence from endpoint systems is available - only the network and its infrastructure.
Students will present their findings at each stage of the exercise. This will test their understanding of the evidence and ability to articulate and support their hypotheses. The audience will include senior-level decision makers, so all presentations must include executive summaries as well as technical details. Time permitting, students should also include recommended steps that could help to prevent, detect, or mitigate a repeat compromise.
CPE/CMU Credits: 6
Network Forensic Case
!!IMPORTANT - BRING YOUR OWN SYSTEM CONFIGURED USING THESE DIRECTIONS!!
You can use any 64-bit version of Windows, MAC OSX, or Linux as your core operating system that also can install and run VMware virtualization products.
It is critical that your CPU and operating system support 64-bit so that our 64-bit guest virtual machine will run on your laptop. VMware provides a free tool for Windows and Linux that will detect whether or not your host supports 64-bit guest virtual machines. For further troubleshooting, this article also provides good instructions for Windows users to determine more about the CPU and OS capabilities. For Macs, please use this support page from Apple to determine 64-bit capability.
Please download and install VMware Workstation 10, VMware Fusion 6.0, or VMware Player 6.0 or higher versions on your system prior to class beginning. If you do not own a licensed copy of VMware Workstation or Fusion, you can download a free 30-day trial copy from VMware. VMware will send you a time-limited serial number if you register for the trial at their Web site. VMware Player is a free download that does not need a commercial license. Most students find VMware Player adequate for the course. Please note that other virtualization software is not supported in the lab environment, and may not successfully run the supplied virtual machines.
MANDATORY FOR572 SYSTEM HARDWARE REQUIREMENTS:
MANDATORY FOR572 SYSTEM SOFTWARE REQUIREMENTS (Please install the following prior to the beginning of the class):
OPTIONAL ITEMS TO BRING TO CLASS
If you have additional questions about the laptop specifications, please contact firstname.lastname@example.org.
|Who Should Attend|
|What You Will Receive|
|You Will Be Able To|
|Press & Reviews|
"I feel like I have won the lottery with the wealth of information from this week! Very relevant and applicable. I have already started using in our environments with results." -Charlie H.
"This is an incredible curriculum. This class NEEDED to happen and I am glad it did." -Peter Steinmann
"Cutting edge - puts me ahead in the job market." -Anonymous
"Very good real-world material." -Jason Lawrence
"Great resource. Only true network forensics course I know of." -Jeremy Robbins
"If you are into disk/memory forensics, you will need this, too!" -Wouter Jansen
"This class is immediately applicable to my work environment." -Thomas Heffron
"No FLUFF - focused and targeted learning!" -Jackie Stokes
"Awesome! Best SANS course I have taken!" -Jim Horvath
"Although FOR572 is a network forensics class, it gets exactly right what most incident response courses get wrong. Instead of focusing on specific exploits and malware that quickly become outdated, 'Advanced Network Forensics' taught me about the full range of evidence sources available and how to effectively mine them for clues. Even more importantly, FOR572 taught me how to use different evidence sources to fill in missing gaps. This is critical, as most environments or incidents will not have every type of evidence available. A large scale APT breach will not have full packet capture available for what could be over a year of attacker activity, but making effective use of network log files can fill in those gaps. It also dove into advanced topics like analyzing unknown protocols, which is an important skill when dealing with the ever-evolving landscape of malware and odd but legitimate applications. Finally, the network forensics capstone investigation is a small but realistic simulation of an APT breach. Having to perform a realistic investigation under the pressure of limited in-class hours felt much like the pressures of investigating a live incident under the pressure of stopping ongoing data theft. It is an excellent class, and I would definitely recommend it to anyone wanting to bring their IR skills to the next level." - Alexander Bond, Mandiant
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