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Vulnerability Assessment Details

Firewall ECE-bit bypass

Vulnerability Assessment Summary
Firewall ECE-bit bypass

Detailed Explanation for this Vulnerability Assessment

The remote host seems vulnerable to a bug wherein a remote
attacker can circumvent the firewall by setting the ECE bit
within the TCP flags field. At least one firewall (ipfw) is
known to exhibit this sort of behavior.

Known vulnerable systems include all FreeBSD 3.x ,4.x, 3.5-STABLE,
and 4.2-STABLE.

Solution: If you are running FreeBSD 3.X, 4.x, 3.5-STABLE,
4.2-STABLE, upgrade your firewall. If you are not running FreeBSD,
contact your firewall vendor for a patch.

See also: http://www.securityfocus.com/bid/2293/
Risk Factor: High

Networks Security ID: 2293

Vulnerability Assessment Copyright: This script is Copyright (C) 2004 Andrey I. Zakharov and John Lampe

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