SyncEvolution sends Basic Auth in its initial request, to avoid round-trips. If http with Digest Auth is used, then this behavior exposes the credentials. SyncEvolution should only send Basic Auth over https. See bug #56240 comment #4.
Fix is in master, will be in 1.3.99.3: commit 68ef2f37dd2490e90fc3dad4b97d8ab3e893f108 Author: Patrick Ohly <patrick.ohly@intel.com> Date: Mon Mar 4 07:05:56 2013 -0800 WebDAV: don't send Basic Auth via http (FDO #57248) Sending basic authentication headers via http is insecure. Only do it when the connection is encrypted and thus protects the information.
The commit introduced a regression, fixed in this: WebDAV: send Basic Auth via http in some cases (FDO #57248) It turned out that finding databases on an Apple Calendar server accessed via http depends on sending Basic Auth even when the server does not ask for it: without authentication, there is no information about the current principal, which is necessary for finding the user's databases. To make this work again, sending the authentication header is now forced for plain http if (and only if) the request which should have returned the principal URL fails to include it. This implies sending the same request twice, but as this scenario should be rare in practise (was only done for testing), this is acceptable.
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