File Extraction

In some occasions (a forensics or stego case) you will have a file (disk image, memory dump, zip file, image…) that will have more files embedded on it (especial efforts may have made to hide them). In these cases, there are a bunch of tools you can try to extract all of the embedded files.
Remember that it’s possible that each tools will uncover different files.

Extraction tools

Autopsy

The most common tool used in forensics to extract files from images is Autopsy. Download it, install it and make it ingest the file to find “hidden” files. Note that Autopsy is built to support disk images and other kind of images, but not simple files.

Binwalk

Binwalk is a tool for searching binary files like images and audio files for embedded files and data.
It can be installed with apt however the source can be found on github.
Useful commands:

sudo apt install binwalk #Insllation
binwalk file #Displays the embedded data in the given file
binwalk -e file #Displays and extracts some files from the given file
binwalk --dd ".*" file #Displays and extracts all files from the given file

Foremost

Another common tool to find hidden files is foremost. You can find the configuration file of foremost in /etc/foremost.conf. If you just want to search for some specific files uncomment them. If you don’t uncomment anything foremost will search for it’s default configured file types.

sudo apt-get install foremost
foremost -v -i file.img -o output
#Discovered files will appear inside the folder "output"

Scalpel

Scalpel is another tool that can be use to find and extract files embedded in a file. In this case you will need to uncomment from the configuration file (/etc/scalpel/scalpel.conf) the file types you want it to extract.

sudo apt-get install scalpel
scalpel file.img -o output

Bulk Extractor

This tool comes inside kali but you can find it here: https://github.com/simsong/bulk_extractor

This tool can scan an image and will extract pcaps inside it, network information(URLs, domains, IPs, MACs, mails) and more files. You only have to do:

bulk_extractor memory.img -o out_folder

Navigate through all the information that the tool has gathered (passwords?), analyse the packets (read Pcaps analysis), search for weird domains (domains related to malware or non-existent).

FindAES

Searches for AES keys by searching for their key schedules. Able to find 128. 192, and 256 bit keys, such as those used by TrueCrypt and BitLocker.

Download here.

Complementary tools

You can use viu to see images form the terminal.
You can use the linux command line tool pdftotext to transform a pdf into text and read it.