A day in the life of a Malware Analyst

When it comes to analyzing malware, each company has its own methods. Due to the volume of daily threats, most vendors will develop some sort of automation to process hundreds of signatures very rapidly. However, human analysts are needed to understand the mechanisms used by malware authors.

I can see at least two ways of analyzing a piece of malware:

- reverse engineer it
- execute it

Reverse engineering consists of taking apart the sample to understand how it works. Basically, the file is made of instructions written in the source code. When a malware author (or anybody) writes a program, they will compile all those instructions into a language that the machine can understand. The job of the security analyst is to go back to those lines of codes in order to reveal the hacker’s intentions.

Needless to say that this is a lengthy and sometimes difficult process. Also, the security analyst needs to have the proprer skills to understand different programming languages and identify the portions of code that present a security risk.

The other alternative to reverse engineering is much more simple and quicker but radically different. While the first method was mainly static, the second one consists of running the sample on a machine.
Security analysts use special machines, such as virtual environments, or machines that can be infected, formated and re-installed.
Samples are run and their behaviour is recorded. That behaviour is also called payload and includes: file creation, registry modification, network traffic etc.
At that point it is fairly easy to identify behaviours . When in doubt we upload the sample or a file from its payload to an online malware scanner. That can help us classify the sample into a category (i.e. Password Stealing Trojan).

In order to protect our end users, we must add the malware “payload” to our security products.  Here we use the term signature which is made of file names, paths (i.e. c:\windows), and other uniquely identifiable information such as MD5.
We regularly release database updates that include the latest threats we found.

Another part of malware analysis deals with cleaning malware samples we have added to our products. Here we want to make sure that our software is capable of removing all infections without damaging the Operating System.

The loop has been completed, from malware infection, to detection and finally removal.

There goes the day of a Malware Analyst

JSegura