Thursday, December 31, 2015

Extracting without installing
7-Zip for All...! We can easily extract many installer types with this "little tool that can" do so much :) Even other archiver based on it like Bandizip can't do all of 7-Zip can.
   And its "Open archive" prowess is so useful in identifying what kind of installer an executable is. We will see this prowess later in analyzing each installer type. The basic rule is to try to open any installer executable with 7-Zip first.

NSIS Installer

A good open source installer package that's very friendly with 7-Zip comes from our good old portable application developer's buddy: NSIS/Nullsoft Scriptable Install System.

   We will show you an example in which we have the chance to use some of 7-Zip neatest feature on the WPS Office installer executable. Let's open this archive, Open archive
   As we can see here, there's a $PLUGINSDIR folder. This is the most typical property of an NSIS installer. $PLUGINSDIR
   A glance at the "Packed Size" column, it's obvious that it stores most of its files in $_11_ folder, so let's go inside. There we find the main installer file called the $EXEFILE, $EXEFILE
   Let's right-click on it and select Open Inside, Open Inside
   Here we find a CONTROL folder without anything meaningful inside it. After all, its total size is only about 0.7MB, CONTROL folder
   Let's move up again to $EXEFILE but now let's try Open Inside * (with asterisk),Something big
   We got something big called [0]. If we select Open Inside on [0] it will open that CONTROL folder again—same thing with Open Inside *.
   So let's now try that Open Inside # (with hash/fence), and it brings up something that 7-zip can recognize!
Open Inside #
Something known
   Now let's open the biggest archive called 4.7z with Open Inside and we finally find what we're looking for, Open the biggest one
Found it

By the way, we can save time by opening the $EXEFILE with Open Inside # directly and find that 4.7z and the "bonanza" inside, Open Inside #
4.7z
bonanza
   That's why we really love 7-Zip!