The Life of Binaries
The Life of Binaries
Topics include but are not limited to:
- Scanning and tokenizing source code.
- Parsing a grammar.
- Different targets for x86 assembly object files generation. (E.g. relocatable vs. position independent code).
- Linking object files together to create a well-formed binary.
- Detailed descriptions of the high level similarities and low level differences between the Windows PE and Linux ELF binary formats.
- How an OS loads a binary into memory and links it on the fly before executing it.
Along the way we discuss the relevance of security at different stages of a binary’s life, from the tricks that can be played by a malicious compiler, to how viruses really work, to the way which malware “packers” duplicate OS process execution functionality, to the benefit of a security-enhanced OS loader which implements address space layout randomization (ASLR).
Lab work includes:
- Using the new “Binary Scavenger Hunt” tool which creates randomized PE binaries and asks randomized questions about the material you just learned!
- Manipulating compiler options to change the type of assembly which is output.
- Manipulating linker options to change the structure of binary formats.
- Reading and understanding PE files with PEView.
- Reading and understanding ELF files with Readelf.
- Using WinDbg and/or GDB to watch the loader dynamically link an executable.
- Using Thread Local Storage (TLS) to obfuscate control flow and serve as a basic anti-debug mechanism.
- Creating a simple example virus for PE.
- Analyze the changes made to the binary format when a file is packed with UPX.
- Using the rootkit technique of Import Address Table (IAT) hooking to subvert the integrity of a program’s calls to external libraries, allowing files to be hidden.
- Do a deep dive into the big picture of how binaries are executed on most OSes.
- Provide detailed information about Windows/Linux binary formats which will be useful to future reverse engineers.
- Show the security-relevance of knowledge about all stages of a binary's life.
The materials within this course focus on the Knowledge Skills and Abilities (KSAs) identified within the Specialty Areas listed below. Click to view Specialty Area details within the interactive National Cybersecurity Workforce Framework.
If you would like to provide feedback for this course, please e-mail the NICCS SO at NICCS@hq.dhs.gov.