Circular reference when outputting JSON with starttls

[MWedl]

Describe the bug
When using the JSON output with option --starttls=pop3 or imap and the server does not support STARTTLS, sslyze fails with an error indicating a "circular reference". When using --starttls=smtp no circular reference error occurs.

To Reproduce
Steps to reproduce the behavior:

1. Install SSLyze using '...' [e.g. pip, git]
2. Run the following command 'sslyze --regular --json_out=- --starttls=pop3 mail.server.com:110'
3. See error

Traceback (most recent call last):
  File "/usr/bin/sslyze", line 11, in <module>
    load_entry_point('sslyze==2.0.6', 'console_scripts', 'sslyze')()
  File "/usr/lib/python3/dist-packages/sslyze/__main__.py", line 117, in main
    output_hub.scans_completed(exec_time)
  File "/usr/lib/python3/dist-packages/sslyze/cli/output_hub.py", line 69, in scans_completed
    out_generator.scans_completed(total_scan_time)
  File "/usr/lib/python3/dist-packages/sslyze/cli/json_output.py", line 79, in scans_completed
    self._json_dict, default=_object_to_json_dict, sort_keys=True, indent=4, ensure_ascii=True
  File "/usr/lib/python3.7/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.7/json/encoder.py", line 201, in encode
    chunks = list(chunks)
  File "/usr/lib/python3.7/json/encoder.py", line 431, in _iterencode
    yield from _iterencode_dict(o, _current_indent_level)
  File "/usr/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "/usr/lib/python3.7/json/encoder.py", line 325, in _iterencode_list
    yield from chunks
  File "/usr/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "/usr/lib/python3.7/json/encoder.py", line 439, in _iterencode
    yield from _iterencode(o, _current_indent_level)
  File "/usr/lib/python3.7/json/encoder.py", line 436, in _iterencode
    raise ValueError("Circular reference detected")
ValueError: Circular reference detected

Expected behavior
A error message in JSON, like with --starttls=smtp.

Python environment (please complete the following information):

• OS: Kali Linux
• Python version: 3.7

[RaheelaKhan1172]

Try upgrading sslyze, I think nabla-c0d3 fixed this error -
default=_object_to_json_dict is removed from json_output.py and ssylze is on version 2.1.3 now instead of 2.0.6

[nabla-c0d3]

Yes it was fixed in 2.1.2.

[MWedl]

@nabla-c0d3 @RaheelaKhan1172 I updated sslyze to version 2.1.3 but the error still persists.

sslyze --tlsv1_2 --json_out=- --starttls=pop3 mail.server.com:110                                                                                                                                    127 ↵
Traceback (most recent call last):
  File "/usr/local/bin/sslyze", line 10, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.7/dist-packages/sslyze/__main__.py", line 125, in main
    output_hub.scans_completed(exec_time)
  File "/usr/local/lib/python3.7/dist-packages/sslyze/cli/output_hub.py", line 77, in scans_completed
    out_generator.scans_completed(total_scan_time)
  File "/usr/local/lib/python3.7/dist-packages/sslyze/cli/json_output.py", line 69, in scans_completed
    json_out = json.dumps(self._json_dict, cls=_CustomJsonEncoder, sort_keys=True, indent=4, ensure_ascii=True)
  File "/usr/lib/python3.7/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.7/json/encoder.py", line 201, in encode
    chunks = list(chunks)
  File "/usr/lib/python3.7/json/encoder.py", line 431, in _iterencode
    yield from _iterencode_dict(o, _current_indent_level)
  File "/usr/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "/usr/lib/python3.7/json/encoder.py", line 325, in _iterencode_list
    yield from chunks
  File "/usr/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "/usr/lib/python3.7/json/encoder.py", line 439, in _iterencode
    yield from _iterencode(o, _current_indent_level)
  File "/usr/lib/python3.7/json/encoder.py", line 436, in _iterencode
    raise ValueError("Circular reference detected")
ValueError: Circular reference detected

[RaheelaKhan1172]

I see, I was able to reproduce this. I have a fix for it!