├── .gitignore
├── README.md
└── flutter_extractor.py


/.gitignore:
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103 | # mypy
104 | .mypy_cache/
105 | 


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/README.md:
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 1 | # flutter_extractor
 2 | Extracting strings and function names from Flutter apks, based on this blogpost - https://medium.com/@rondalal54/reverse-engineering-flutter-apps-5d620bb105c0
 3 | 
 4 | ## Usage
 5 | ```
 6 | flutter_extractor.py [OPTIONS] APP_PATH
 7 | 
 8 | app_path: path to the extracted apk directory (the output directory of the apktool)
 9 | 
10 | Options:
11 |   --out TEXT  The output dir
12 |   --help      Show this message and exit.
13 | ```
14 | **Please use [ApkTool](https://ibotpeaches.github.io/Apktool/) or jadx** before running the extractor. Due to the fact that APKs are somewhat a zip file, there's need to extract the files first, for the extractor to use them.
15 | 
16 | ## Example
17 | ```python flutter_extractor.py /path/to/extracted_apk/ --out ./flutter_data```
18 | 


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/flutter_extractor.py:
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 1 | import click 
 2 | import subprocess
 3 | import os
 4 | import re 
 5 | 
 6 | # Could be changed due to changes in the Flutter engine  
 7 | DATA_FILE = "isolate_snapshot_data"
 8 | POSSIBLE_DATA_TYPES = [{"type": "functions", 
 9 |                     "pattern":b"([a-zA-Z_]{1}\w+)@[0-9]+",
10 |                      "filename": "functions"},
11 |                      {"type": "strings", # including functions 
12 |                     "pattern":b"[\w]{4,}",
13 |                     "filename": "strings"}]
14 | 
15 | def get_data_from_snapshot(app_path):
16 |     data_path = os.path.join(app_path, "assets", "flutter_assets", DATA_FILE)
17 |     data = ""
18 | 
19 |     with open(data_path, 'rb') as data_file_handle:
20 |         data = data_file_handle.read()
21 | 
22 |     return data
23 | 
24 | def extract_by_pattern_to_file(data, pattern, out_path):
25 |     extracted_strings = set(re.findall(pattern, data)) # using set() to remove duplicates
26 |     extracted_strings = b"\n".join(extracted_strings)
27 | 
28 |     click.echo("Writing to %s" % out_path)
29 |     with open(out_path, "wb") as file_handle:
30 |         file_handle.write(extracted_strings)
31 | 
32 | def mkdir_if_not_exist(directory):
33 |     if not os.path.exists(directory):
34 |         os.makedirs(directory) 
35 | 
36 | @click.command()
37 | @click.option('--out', default="./flutter_data", help='The output dir')
38 | @click.argument('app_path')
39 | def main(app_path, out):
40 |     """app_path: path to the extracted apk directory (for example - output directory of the apktool)"""
41 |     mkdir_if_not_exist(out)
42 | 
43 |     click.echo("Reading from the isolate data file...")
44 |     data = get_data_from_snapshot(app_path)
45 | 
46 |     for data_type in POSSIBLE_DATA_TYPES:
47 |         out_path = os.path.join(out, data_type["filename"])
48 |         extract_by_pattern_to_file(data, data_type["pattern"], out_path)
49 | 
50 | if __name__ == '__main__':
51 |     main()
52 | 


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