I'd say it's definitely possible, if not likely.
For starters, turn off extensions altogether, to verify that they're causing the issues. Then I'd suggest disabling them one at a time (which sounds like you've tried partly), until you can isolate which one is causing the issues.
If that doesn't help (but all extensions off does), then try only one of your Javascript blockers at once, in the event that some conflict between them is causing problems.
I can confirm that I see the identical problem with Safari 7.0.2 (9537.74.9), with all current Mac OS X Mavericks updates installed. (Thousands of request packets per second with the same kind of content as described above.)
However, while this may or may not help the original poster, I have found that this problem only occurs if the Windows server has Integrated Windows Authentication (also known as NTLM Authentication) and Negotiate Authentication enabled.
The server then sends these two headers:
WWW-Authenticate: Negotiate
WWW-Authenticate: NTLM
Safari will reply:
Authorization: Negotiate YEgGBisGAQUFAqA+MDygDjAMBgorBgEEAYI3AgIKoioEKE5UTE1TU1AAAQAAAAUCiGIAAAAAGAAAAAAAAAAYAAAABgGwHQ8AAAA=
And from there, the loop will get going.
But if Negotiate Authentication is not enabled on the server, there will be only one WWW-Authenticate header:
WWW-Authenticate: NTLM
And Safari's reply will be something like:
Authorization: NTLM TlRMTVNTUAABAAAAB4IIAAAAAAAAAAAAAAAAAAAAAAA=
This will work just fine. Essentially, it seems that Negotiate is broken in Safari, and since the server sends Negotiate first, indicating a preference for it, Safari will try it and enter an infinite loop that prevents it from falling back to NTLM.
So, if the server administrator can be persuaded to turn off Negotiate in the authentication settings, the problem may be solved.
I might add that Firefox sends the "Authorization: NTLM ..." header regardless of whether the server provides Negotiate in addition to NTLM or not. Presumably, Negotiate is not implemented in Firefox.
Update
Safari 7.0.3 (9537.75.14) still exhibits the same problem.
We previously reported the issue as a bug at bugreport.apple.com, but the bug was closed as a duplicate of a previous bug—the contents of which we cannot see, except that it is still marked as open.
Update 2
I can confirm hauns's finding that the authentication works with Safari 7.0.4 (9537.76.4).
Update 3
This issue is back in Safari 7.0.5 (9537.77.4)
Update 4
This issue is still present in Safari 7.0.6 (9537.78.2), as noted by hauns, with cifs or smb volumes mounted.
Best Answer
Seems like this an issue with digicert's OCSP and Роскомнадзор. macOS tries to check certificate revocation every time when you change Safari tab with digicert certificate, but IP address is blocked by provider. Same issue with App Store downloads.
I've added different IP address to the
/etc/hosts:72.21.91.29 ocsp.digicert.comand everything works fine for me now.
Also you can try other solutions or check details from https://stackoverflow.com/questions/39899002/github-is-painfully-slow-on-safari-macos-sierra-10-12