Ozwillo invitation emails marked as spam by SpamAssassin

[bobeal]

From @vdachev on December 9, 2015 9:13

We have a SpamAssassin deployed in our organization. Yesterday I received two organization invitation emails (one for the prod and another for the pre-prod) and they got marked as spam, due to the following reasons:

One of them (the pre-prod one) got 6.4 pts (threshold is 5.5 pts):

pts	rule name	description
-0.0	SPF_HELO_PASS	SPF: HELO matches SPF record
0.4	URIBL_GREY	Contains an URL listed in the URIBL greylist [URIs: mj.am]
2.1	HTML_IMAGE_ONLY_12	BODY: HTML: images with 800-1200 bytes of words
1.5	BAYES_60	BODY: Bayes spam probability is 60 to 80% [score: 0.6781]
0.0	HTML_MESSAGE	BODY: HTML included in message
0.7	MIME_HTML_ONLY	BODY: Message only has text/html MIME parts
0.8	RDNS_NONE	Delivered to internal network by a host with no rDNS
0.0	T_DKIM_INVALID	DKIM-Signature header exists but is not valid
2.0	LIST_PARTIAL_SHORT_MSG	Incomplete mailing list headers + short message
0.0	T_REMOTE_IMAGE	Message contains an external image
-1.1	AWL	AWL: Adjusted score from AWL reputation of From: address

The other one (the prod one) got 6.0 pts (threshold is 5.5 pts):

pts	rule name	description
0.4	URIBL_GREY	Contains an URL listed in the URIBL greylist [URIs: mj.am]
-0.0	SPF_HELO_PASS	SPF: HELO matches SPF record
0.0	HTML_MESSAGE	BODY: HTML included in message
1.7	HTML_IMAGE_ONLY_08	BODY: HTML: images with 400-800 bytes of words
0.8	BAYES_50	BODY: Bayes spam probability is 40 to 60% [score: 0.5296]
0.7	MIME_HTML_ONLY	BODY: Message only has text/html MIME parts
0.8	RDNS_NONE	Delivered to internal network by a host with no rDNS
0.0	T_DKIM_INVALID	DKIM-Signature header exists but is not valid
2.0	LIST_PARTIAL_SHORT_MSG	Incomplete mailing list headers + short message
-0.4	AWL	AWL: Adjusted score from AWL reputation of From: address

Copied from original issue: ozwillo/ozwillo-portal#353

[bobeal]

From @mdutoo on December 9, 2015 15:6

That's actually a Kernel problem (and different from #226 mailjet spamtrapped).

My 2 cents: at the very least the header & missing text MIME issues can be addressed.