#453 FORGED_MUA_THEBAT_CS: The Bat! and Spamassassin
The mail user agent "The Bat!" creates header lines like this if there is some non-ascii character like a umlaut (ä):
X-Mailer: The Bat! (v2.00)
Content-Type: text/plain; charset=ISO-8859-15
"The Bat!" never puts quotes around the charset. Mailman's Decorate.py changes this to:
X-Mailer: The Bat! (v2.00)
Content-Type: text/plain; charset="iso-8859-15"
Spamassassin has a spam detection rule that triggeres if X-Mailer contains "The Bat!" and there are quotes around the charset. The rule is named FORGED_MUA_THEBAT_CS and is located in rules/20_ratware.cf
http://svn.apache.org/repos/asf/spamassassin/tags/spamassassin_release_3_2_3/rules/20_ratware.cf
My patch renames X-Mailer to X-X-Mailer. That prevents triggering the rule without information loss.
I've tested the patch that applies to 2.1.7 and it works for me. I havn't tested the patch for trunk (8228).
rename X-Mailer: The Bat! to X-X-Mailer: The Bat!
rename X-Mailer: The Bat! to X-X-Mailer: The Bat!
Logged In: YES
user_id=561017
Originator: YES
File Added: Decorate.py-8228.diff
Logged In: YES
user_id=1123998
Originator: NO
If you really want to nullify this spamassassin test, why not just put
score FORGED_MUA_THEBAT_CS 0 0 0 0
in the appropriate spamassassin user_prefs file?
Logged In: YES
user_id=561017
Originator: YES
Mailman delivers the email to all subscribers of the mailing list. Spamassassin runs on the mail servers of the subscribers. I don't have access to the configuration of these mail servers, so I cannot nullify that spamassassin test.
For discussing improvements to spamassassin regarding this bug please use http://issues.apache.org/SpamAssassin/show_bug.cgi?id=5658
However, as many sites don't update spamassassin frequently we should consider patching Mailman as well.