import re
s = """
user "username"
password "P@ssword"
dbname "SOME_DB_NAME"
"""
r = re.compile(r'({}\s")[\w@#$%^&*]+"'.format('password'))
print(r.sub(r'\1new_passw0rd"', s))
aW1wb3J0IHJlCgpzID0gIiIiCnVzZXIgInVzZXJuYW1lIgpwYXNzd29yZCAiUEBzc3dvcmQiCmRibmFtZSAiU09NRV9EQl9OQU1FIgoiIiIKciA9IHJlLmNvbXBpbGUocicoe31ccyIpW1x3QCMkJV4mKl0rIicuZm9ybWF0KCdwYXNzd29yZCcpKQpwcmludChyLnN1YihyJ1wxbmV3X3Bhc3N3MHJkIicsIHMpKQ==