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layout: post title: "Software Security Notes 4 Basic Binary Analysis in Linux" date: 2021-3-2 07:00:00 +0800

categories: [Notes, Software Security]

Basic Binary Analysis in Linux

Tools

GNU Binutils tools:

• c++filt
• objdump
• readelf
• strings
• nm
• base64
• file
• ldd
• strace
• ltrace
• xxd
• hexedit
• dd

CTF Walkthrough

1. Identify the payload

base64:
represent binary in a textual form using "=" as padding

Use $base64$ to encode and decode.
Use $file$ to identify the type of file.
Use $ldd$ to identify dependencies.

2. Finding the missing shared library

Use $xxd$ to find ELF header.
Use $dd$ to extract.

ELF header is 64 bytes.

3. Extracting the shared library

Size of the file = Start of section headers + (Number of section headers * Size of section headers)