SpamAssassin Rule: RATWARE_MS_HASH
Standard description: Bulk email fingerprint (msgid ms hash) found
Explanation
The Message-Id in the header seems to be generated using a scheme found in Microsoft software, but has no other identifiers to confirm that this software was used. This is known to be a possible ratware identifier.
Further Info
The default scores for this rule can be found in the online list of tests.