_mask_credentials uses UGC in a regex substitution

[barm]

I recently ran into an issue when testing passwords with whitespace characters on an app with silk installed. I found that if I have multiple consecutive spaces in a password (which silk treats as a sensitive field and tries to mask), the regex substitution in _mask_credentials fails. This is because the user input is used as a pattern in a re.sub and so if the user uses certain characters, they are interpreted as a regex pattern. Space here in the raw_body is a literal +. This seems unsafe.

for res in results:
    body = re.sub(res[1], RequestModelFactory.CLEANSED_SUBSTITUTE, body)

From: https://github.com/jazzband/django-silk/blob/master/silk/model_factory.py#L131

Is there any reason we can't do a simple string replace instead?

for res in results:
    body = body.replace(res[1], RequestModelFactory.CLEANSED_SUBSTITUTE)