Sun Solaris 7 through 9, when Basic Security Module (BSM) is enabled and the SUNWscpu package has been removed as a result of security hardening, disables mail alerts from the audit_warn script, which might allow attackers to escape detection.
https://exchange.xforce.ibmcloud.com/vulnerabilities/15042
http://www.securityfocus.com/bid/13724
http://www.ciac.org/ciac/bulletins/o-070.shtml
http://sunsolve.sun.com/search/document.do?assetkey=1-26-57483-1