Silva97 / pei

PE Injector - Inject code on 32-bit and 64-bit PE executables

pei - PE Injector

Command-line tool for inject code and manipulate PE32 (32-bit) and PE32+ (64-bit) executables.

With pei you can:

• Display informations about the executable like COFF header, sections and more.
• Get individual values from fields of the headers to manipulate the values by scripts. Example: pei get test.exe optional.entry_point '0x%x' - Will print 0x12345
• Edit individual fields. Example: pei edit test.exe optional.entry_point = 0xabcd
• Manipulate memory access permissions to sections of the executable.
• Find zeroed blocks of data on the sections of the executable.
• Inject code to be executed before the OEP of the executable.
• Compares executables and show differences between.

Compilation and installation

Just run the commands below to compile the project:

git clone https://github.com/Silva97/pei
cd pei
cmake -DCMAKE_BUILD_TYPE=Release .
cmake --build . -t pei

Done! pei has no dependencies other than libc. To install, just run:

sudo cmake --install .

If you doesn't want more pei on your system, run sudo make uninstall. :(

How it injects code

With pei you can specify the section to inject the code or leave the tool to select the section with the biggest zeroed block of data. You can run pei z test.exe to gets a list of blocks from all sections of the executable. The entry point of the executable will be updated to point the injected code, and at end of the code a absolute jump to OEP (Original Entry Point) will be added.

Note: After pei writes the code on the section, these as been marked with permission to execute code and the dynamic base of the executable will be disabled.

Basic Usage

pei [options] <operation> <executable> [argument]

Argument	Descrption
operation	First letter or full name of the operation to do with executable
executable	PE32 or PE32+ executable

Note: You can run pei -h to get full help about usage of the tool.

Examples

pei s test.exe         # Show general informations about the executable
pei -vs0 s test.exe s  # Show first section in verbose mode
pei s test.exe d       # Show all data directories
pei s test.exe gc      # Show general informations and COFF header

pei g test.exe optional.entry_point '%x'         # Entrypoint in hexadecimal
pei g test.exe optional.iat.virtual_address '%x' # Virtual address of IAT structure
pei g test.exe section.0.name '%s'               # Name of the first section

pei e test.exe section.0.name = .code            # Edit the name of the first section
pei e test.exe optional.entry_point = 0xaabb1234 # Edit the entry point

# Inject code from `payload` raw binary file to `test.exe` entry point
pei -f payload i test.exe

# Replicates the modifications on t2.exe for t3.exe
pei diff t1.exe t2.exe | pei patch t3.exe

Tip 1: For see the name of the fields to use with get operation, just use show operation to see all fields of the given structure. Example:

pei show test.exe o

After run the command above, you can see all (except data directories) fields of the optional header.

Tip 2: Remember that the data directories are in the optional header.