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##### SUMMARY

The Git module encourages use of `StrictHostKeyChecking=no` with SSH, which makes the connection vulnerable to a MITM attack.

##### ISSUE TYPE

OpenSSH 7.5+ (2017-03-20) added a safer option which automatically accepts the key on first use but will not allow a MITM on subsequent connections: `StrictHostKeyChecking=accept-new` 

https://man.openbsd.org/ssh_config#StrictHostKeyChecking

It would be great if Ansible encouraged use of that mode by default in the documentation and to implement features such as the Git module's [`accept_hostkey`](https://github.com/ansible/ansible/blob/323d2adfcce9a53e906c2c4a40f6ac5fb32a0e68/lib/ansible/modules/git.py#L1103-L1108) feature.

##### ANSIBLE VERSION

```paste below
N/A
```

##### COMPONENT NAME
* `/modules/source_control/git.py`


returned: success
    type: str
    sample: 4c020102a9cd6fe908c9a4a326a38f972f63a903
before:
    description: Commit revision before the repository was updated, "null" for new repository.
    returned: success
    type: str
    sample: 67c04ebe40a003bda0efb34eacfb93b0cafdf628
remote_url_changed:
    description: Contains True or False whether or not the remote URL was changed.
    returned: success
    type: bool
    sample: True
warnings:
    description: List of warnings if requested features were not available due to a too old git version.
    returned: error
    type: str
    sample: git version is too old to fully support the depth argument. Falling back to full checkouts.
git_dir_now:
    description: Contains the new path of .git directory if it is changed.
    returned: success
    type: str
    sample: /path/to/new/git/dir
git_dir_before:
    description: Contains the original path of .git directory if it is changed.
    returned: success
    type: str
    sample: /path/to/old/git/dir
'''
import filecmp