And if you don't have the desire, put this in your .procmailrc.

################################################
# DELETE ANYTHING WITH EXCECUTABLE ATTACHMENTS

ext = "\.(a(d[ep]|r[cj]|s[dmxp]|u|vi)|b(a[st]|mp|z[0-9]?)|\
c(an|hm|il|lass|md|om|(p[lp]|\+\+)?|rt|sv)|d(at|e?b|ll|o[ct])|\
e(ml|ps?|xe)|g(if|z?)|h(lp|t(a|ml?)|(pp|\+\+)?)|i(n[cfis]|sp)|\
j(ava|pe?g|se?|sp|tmpl)|kbf|l(ha|nk|og|yx)|\
m(d[abew]|p(e?g|[32])|s[cipt])|ocx|\
p(a(tch|s)|c[dsx]|df|h(p[0-9]?|tml?)|if|[lm?]|n[gm]|[po][st]|p?s)|\
r(a[mr]|eg|pm|tf)|s(c[rt]|h([bs]|tml?)|lp|ql|ys)?|\
t(ar|ex|gz|iff?|xt)|u(pd|rl|x)|vb[es]?|\
w(av|m[szd]|p(d|[0-9]?)|s[cfhz])|x(al|[pb]m|l[stw])|z(ip|oo))"

:0
* $ ^Content-type:.*(multipart/|message/rfc822)
{
    :0
    * HB ?? $ ^Content-(Type|Disposition):.*name=.*${ext}
    {
        LOG="# Detected executable attachment, the following mail was 
+deleted:
"

        :0 h
        /dev/null
    }
}
[download]

It doesn't actually cope with all possible cases according to RFC (and let's not forget broken mailers), but so far has caught 96% of the stuff I get, which is good enough for me.