I would like to share my experience and understanding with regards to forensics and where I started to get a foothold in forensics.
Questions that I normally get : I want to get into forensics. What should I study? What kind of certificates are good? What background should I have?
By this blog I will answer those question based on my experience. I will not dwell into explaining what forensics is and why do we perform that. For that you can just google it and/or read my blog entry – Incident Response and Forensics : The Two Towers. Understand Forensics is considered a specialised field, meaning one must have prior knowledge of fundamentals in operating systems, networking, packet analysis, incident handling etc.
For me I started in Technical Support – this is first due to I was a student and second technical support guys will go through numerous issues and fix through out the day which can be extended into Forensics investigation. For example, a user calls into saying my system is working slow – a tech support guy will first investigate why and provide solution/workaround based on the findings. This helped in understanding system internals especially Windows. One must understand how an operating system works – their processes, services, kernel level attributes etc. A very good link to start is here for windows, here for MacOSX and here for linux. I will be creating mind map for this and will provide them on my github account.
Certificates such as SANS GCFE will give you insights on windows operating system forensics. Individuals thinking of this course should read on here.
Other courses and comparison can be viewed here.
We obviously need tools to perform forensics. There are numerous tools available to perform forensics based on what is required. SANS has their own linux distribution SIFT and further information can be found here.
There is also a debate, that System Admins are the best Forensic examiners or investigators and I don’t agree with that statement. Yes system admins have knowledge of system, however that’s mostly into hardening and fixing an issue. Rarely security aspect is covered in System Admin side. System Admin will still need to learn and/or go through training (self or class based) and understand how their experience overlaps in forensics.
To gain a bit more knowledge about networking, incident handling, packet analysis I dwelled into SOC (security operations centre). This allowed me to understand how operating system communicates to other operating systems, network and/or external systems. In SOC, I was responsible to identify anomalies, develop SIEM content to identify incidents within network and/or operating system from a known bad behaviour. This allowed me understand what is a good behaviour. All operating system logs events and one must understand what is the meaning of those and in what situations they are triggered, and how one can use these events in identifying an unauthorised activity and/or unusual behaviour for example. This knowledge, during forensics, allowed me to investigate the operating system and/or infected host in different manner. Yes, Forensics and Incident Response overlaps and are two sides of the same coin. I always took initiatives and that helped me in the field.
To understand how Forensics should be performed one must also understands standards and RFC. Understanding these standards allowed me to grasp how corporate world and/or any forensics practice should perform forensics and how that can be integrated in Incident Response. Have a read here for NIST publication, here for RFC and here for NIST Mobile forensics publication.
This will be a good start to for individuals interested in Forensics. One should also dive into the operating system they normally use at work/home on their laptop/desktop and go through system. For Windows, work on PowerShell, look at the event viewer, services, use Sysinternal Tools. Fire up wireshark and/or Chrome net internals to see what happens when you access a website. Note down whatever is considered a normal behaviour. For linux/Mac look at the logs under directory /var/logs.
Lastly, read the blogs that are forensics and incident response related which will give a good insight in using tools, how forensics is performed and current methodologies and type of investigations.
Few Forensics Blogs :
Another point, I will raise is certifications are not the only way you will understand or gain more knowledge in Forensics. Your practice and dedication in self-learning and implementing on a regular basis will help a lot. But, also in corporate world these certifications are considered an entry point and it is advisable to get them. I have done SANS certifications (I am not advocating them and/or advertising SANS for personal gain, just sharing my personal experience), and I believe they concentrate on fundamentals and have better content with related to topics that are covered in any certifications.
I will be providing more links on the up coming mind map. I will also be providing any Forensic and/or IR investigations that I perform, at my home lab including tools usage.