ipfw and ip6fw in FreeBSD 4.2 and earlier allows remote attackers to bypass access restrictions by setting the ECE flag in a TCP packet, which makes the packet appear to be part of an established connection.Referenceshttp://www.securityfocus.com/bid/2293http://www.ciac.org/ciac/bulletins/l-029.shtmlhttp://www.security-express.com/archives/bugtraq/2001-01/0424.htmlhttps://exchange.xforce.ibmcloud.com/vulnerabilities/5998ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:08.ipfw.aschttp://www.osvdb.org/1743
