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Date: Sat, 20 Sep 2003 14:05:27 -0700
From: Kris Kennaway <kris@obsecurity.org>
To: Pertti Kosunen <pertti.kosunen@kolumbus.fi>
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cc: freebsd-stable@freebsd.org
Subject: Re: [snort] BAD-TRAFFIC loopback traffic 4.9-PRE
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On Sat, Sep 20, 2003 at 08:04:46PM +0300, Pertti Kosunen wrote:
> Source: 127.0.0.1:80 -> Destination: my.inet.ip: ports ~1025-1999
>=20
> >From snorts alert log file, these come ~1000 in a day:
> [**] [1:528:4] BAD-TRAFFIC loopback traffic [**]
> [Classification: Potentially Bad Traffic] [Priority: 2]
> 09/19-22:52:46.419992 127.0.0.1:80 -> my.inet.ip:1821
> TCP TTL:127 TOS:0x0 ID:13627 IpLen:20 DgmLen:40
> ***A*R** Seq: 0x0  Ack: 0x59780001  Win: 0x0  TcpLen: 20
> [Xref =3D> http://rr.sans.org/firewall/egress.php]
>=20
> What could cause this loopback traffic?

Forged source address on a network with no egress filtering.

Kris

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