SSL: WRONG_VERSION_NUMBER

[04fsnape]

Long story short

My program which uses aiohttp to asynchronously connect to a website via multiple instances, all running proxies leads to some errors.

Expected behaviour

I expect them to visit the website without errors.

Actual behaviour

They all work for a bit, then they start giving the error below

15:01:29.600 SSL error in data received
protocol: <asyncio.sslproto.SSLProtocol object at 0x0873A0B0>
transport: <_SelectorSocketTransport fd=1492 read=polling write=<idle, bufsize=0>>
Traceback (most recent call last):
  File "C:\Users\x\AppData\Local\Programs\Python\Python37-32\lib\asyncio\sslproto.py", line 526, in data_received
    ssldata, appdata = self._sslpipe.feed_ssldata(data)
  File "C:\Users\x\AppData\Local\Programs\Python\Python37-32\lib\asyncio\sslproto.py", line 207, in feed_ssldata
    self._sslobj.unwrap()
  File "C:\Users\x\AppData\Local\Programs\Python\Python37-32\lib\ssl.py", line 767, in unwrap
    return self._sslobj.shutdown()
ssl.SSLError: [SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:2609)

Then some give this error

12:33:03.173 SSL handshake failed
protocol: <asyncio.sslproto.SSLProtocol object at 0x095B9A90>
transport: <_SelectorSocketTransport fd=1676 read=polling write=<idle, bufsize=0>>
Traceback (most recent call last):
  File "C:\Users\x\AppData\Local\Programs\Python\Python37-32\lib\asyncio\sslproto.py", line 625, in _on_handshake_complete
    raise handshake_exc
  File "C:\Users\x\AppData\Local\Programs\Python\Python37-32\lib\asyncio\sslproto.py", line 189, in feed_ssldata
Cannot connect to host www.<website>.co.uk:443 ssl:None [[SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:1056)]
    self._sslobj.do_handshake()
  File "C:\Users\x\AppData\Local\Programs\Python\Python37-32\lib\ssl.py", line 763, in do_handshake
    self._sslobj.do_handshake()

And then they completely fail and give this error Cannot connect to host <proxy domain>:<proxy port> ssl:None [Connect call failed ('<proxy ip>', <proxy port>)], as well as this oneCannot connect to host www.<website>.co.uk:443 ssl:None [An existing connection was forcibly closed by the remote host]

Steps to reproduce

Run this with a different HTTP proxy for each instance:

import asyncio
import ClientSession from aiohttp

async def launch(url, ip, port):
    done = False
    proxy = "http://{}:{}".format(ip, port)
    async with ClientSession() as session:
        while not done:
            async with session.get(url, timeout=40, proxy=proxy) as initial:
                html_text = await initial.text()
                if x in html_text:
                    done = True
                else:
                    await asyncio.sleep(60)
        await session.close()


def main():
    tasks = []
    loop = asyncio.get_event_loop()
    for i in range(10):
        task = asyncio.ensure_future(launch(url, ip, port))
        tasks.append(task)
    loop.run_until_complete(asyncio.wait(tasks))


if __name__ == "__main__":
    main()

Your environment

Windows 10 1903, Python 3.7.3, aiohttp client 3.5.4.

[asvetlov]

aiohttp uses Python ssl module defaults.
The connected server uses too old (and insecure) SSL version that is not enabled by default (SSLv2 or SSLv3). See https://docs.python.org/3/library/ssl.html#ssl.SSLContext for creating ssl context with compromised security settings.