RHEL5.5 provides spamassassin-3.2.5-1.el5. Although it appears to have been largely unannounced by the SpamAssassin developers, the 3.2.x series is now in "maintenance mode", which means the only rule updates that are pushed to it are emergency updates: http://marc.info/?l=spamassassin-users&m=127440417913677&w=2 SpamAssassin's effectiveness is largely dependent on timely rule updates. From scoring sample spam messages with both 3.2.5 and 3.3.1, and by diffing the latest rulesets available for both versions, I have found that 3.2.5's ability to detect spam has been non-trivially compromised by the discontinuation of regular rule updates. (In fact, I discovered that 3.2.x had been deprecated while investigating why the RHEL5 SpamAssassin fared poorly at identifying recent spam messages we've been receiving.) I can sympathize that SpamAssassin didn't provide much notice, but you are doing your customers a disservice by shipping this deprecated version of SpamAssassin as the latest available for RHEL5. Please update to at least 3.3.0 (preferably 3.3.1) ASAP.
Cross-filed as Service Request 2029372.
*** This bug has been marked as a duplicate of bug 481616 ***