PCRT (PNG Check & Repair Tool)

Description

PCRT (PNG Check & Repair Tool) is a tool to help check if PNG image correct and try to auto fix the error. It's cross-platform, which can run on Windows, Linux and Mac OS.

It can:

Show image information
Fix PNG header error
Fix wrong IHDR chunk crc due to error picture's width or height
Fix wrong IDAT chunk data length due to DOS->UNIX conversion
Fix wrong IDAT chunk crc due to its own error
Fix lost IEND chunk
Extract data after IEND chunk (Malware programs like use this way to hide)
Show the repaired image
Inject payload into image
Decompress image data and show the raw image
...
Maybe more in the future :)  

Install

• Install Python 3.11

• Install Python dependency packages

  • PIL

• Clone the source code

    git clone https://github.com/sherlly/PCRT.git
    cd PCRT
    python PCRT.py
  

Usage

> python PCRT.py -h
usage: PCRT.py [-h] [-q] [-y] [-v] [-m] [-n NAME] [-p PAYLOAD] [-w WAY]
             [-d DECOMPRESS] [-i INPUT] [-f] [-o OUTPUT]

optional arguments:
-h, --help            show this help message and exit
-q, --quiet           don't show the banner infomation
-y, --yes             auto choose yes
-v, --verbose         use the safe way to recover
-m, --message         show the image information
-n NAME, --name NAME  payload name [Default: random]
-p PAYLOAD, --payload PAYLOAD
                      payload to hide
-w WAY, --way WAY     payload chunk: [1]: ancillary [2]: critical
                      [Default:1]
-d DECOMPRESS, --decompress DECOMPRESS
                      decompress zlib data file name
-i INPUT, --input INPUT
                      Input file name (*.png) [Select from terminal]
-f, --file            Input file name (*.png) [Select from window]
-o OUTPUT, --output OUTPUT
                      Output repaired file name [Default: output.png]

[Notice] without -v option means that assume all IDAT chunk length are correct

Show

• Window:

• Linux:

• Mac OS:

Some Problem:

• For Window:

Can't show the repaired image

1. Find the file named ImageShow.py under the path like X:\Python27\lib\site-packages\PIL\ImageShow.py
2. Find the code return "start /wait %s && ping -n 2 127.0.0.1 >NUL && del /f %s" % (file, file) around line 100 and commented it
3. Add the new code: return "start /wait %s && PING 127.0.0.1 -n 5 > NUL && del /f %s" % (file, file) and save
4. Restart the python IDE

Release Log

version 1.1:

Add：

• Show image information (-m)
• Inject payload into image (-p)
  • add into ancillary chunk (chunk name can be randomly generated or self-defined) (-w 1)
  • add into critical chunk (only support IDAT chunk) (-w 2)
• decompress image data and show the raw image (-d)

version 1.0：

Feature:

• Fix PNG header error
• Fix wrong IHDR chunk crc due to error picture's width or height
• Fix wrong IDAT chunk data length due to DOS->UNIX conversion
• Fix wrong IDAT chunk crc due to its own error
• Fix lost IEND chunk
• Extract data after IEND chunk (Malware programs like use this way to hide)
• Show the repaired image