/etc/postfix/main.cf:
body_checks = regexp:/etc/postfix/body_checks
header_checks = regexp:/etc/postfix/header_checks
/etc/postfix/body_checks:
# Вырезаем EXE файлы.
# в скобках [     ] - один пробел и один символ табуляции.
/^[     ]*name=.*\.(exe|dll|eml|vbs|pif|com|bat|scr|lnk)\"?$/           REJECT
/\<iframe src=cid\:.* height=0 width=0\>/i      REJECT
/^Content-Disposition: attachment; *filename=.*\.(exe|dll|eml|vbs|pif|com|bat|scr|lnk).*/i   REJECT
/etc/postfix/header_checks:
# Sircam
/^Content-Type:multipart.*"----[A-F0-9]+_Outlook_Express_message_boundary"/i    
# Nimbda
/^X-Unsent: 1/  REJECT
/^X-Mailer: Advanced Mass Sender/       REJECT                                 
/^X-Mailer: Mail Bomber/        REJECT                                      
/^X-Mailer: .*\-VC_IPA \[/      REJECT