Metamorfo PowerShell script cleaner

Metamorfo_PS1_Cleaner.py

'''
Tested on the sample (Sha256):
70e303792d1699fc53b9b3251faf7fc66a070a981972ab64783a1a368e4c96f8
'''
import re
from base64 import b64decode

pattern = r'(\$\(\[Text\.Encoding\].*FromBase64String(\(.*\'\))\)\))'
file_handle = open('metamorfo_stage.ps1', 'r').readlines()

for line in file_handle:
    match = re.findall(pattern,line)
    if match:
        b64String = match[0][1]
        line = re.sub(pattern,b64decode(match[0][1]).decode(),line)
        open('metamorfo_stage_cln.ps1','a').write(line.replace('\0',''))
    else:
        open('metamorfo_stage_cln.ps1','a').write(line)

pattern2 = r'^(\$.*) \= (.*)$'
file_handle = open('metamorfo_stage_cln.ps1', 'r').readlines()
replace_list = []
for line in file_handle:
    match = re.findall(pattern2,line)
    if match:
        replace_list.append([match[0][0],match[0][1]])

final = open('metamorfo_stage_cln.ps1', 'r').read()

for replaceArg in replace_list:
    final = final.replace(replaceArg[0],replaceArg[1])
    #print(replaceArg[0])

open('metamorfo_stage_cln.ps1', 'w').write(final)