Re: Strange pings from 127.0.0.1

From: Ranjeet Shetye (ranjeet.shetye2_at_zultys.com)
Date: 06/19/04

  • Next message: captgoodnight_at_acsalaska.net: "Re: False negative on anti sniffing programme." 
    Date: Fri, 18 Jun 2004 15:06:42 -0700
To: security-basics@securityfocus.com

    consider a packet of the type

    Eth_DST=Eth_A
    Eth_SRC=Eth_B
    Eth_Type=IP
    IP_Src=127.0.0.1
    IP_Dst=IP_D

    On Linux - packets from localhost to a local IP dont make it onto the
    network. Assuming the same to be the case on Windows, any target hosts
    (IP_D) that you see ICMPs for, are probably NOT the origin of THIS packet.
    This might help you narrow the possible sources of the traffic.

    Next, (assuming non-promiscuous mode of operation by the NIC) I fail to
    understand how the author of this attack intends to reach his/her targets,
    if the dest MAC addresses are fake! I might be missing something obvious,
    so if someone can point it out to me, that would be great. thanks.

    Instead of an attack, it might be that you have someone on your network
    who is learning socket or libnet programming, and is testing his/her
    networking coding skills on the corporate network. That might explain
    the non-existant destination MAC addresses - which I admit again, don't
    make a lot of sense to me.

    **Unless**, some kind of an ARP-poisoning scheme is being executed,
    so that switches are forced to forward all traffic on all ports cos their
    internal arp tables are messed up.

    In which case, maybe you need to lock down the arp tables in your managed
    switches, if you can.

    I am very curious about this traffic pattern, please let us know the
    answer once you've resolved it. thanks, 

    -- 
Ranjeet Shetye
Senior Software Engineer
Zultys Technologies
Ranjeet dot Shetye at Zultys dot com
http://www.zultys.com/
 
The views, opinions, and judgements expressed in this message are solely those of
the author. The message contents have not been reviewed or approved by Zultys.
* Timothy Schwimer (tschwimer@hotmail.com) wrote:
> Not yet. Doesn't sound like you're having the same issue though. Mine is 
> all ICMP traffic, all sourced from the loopback, but destined to several 
> different host IP's.  In addition, the source and dest MAC are always the 
> same regardless of the IP's.
> I'm fairly certain that I've got a compromised host, but with the source IP 
> being a loopback, I've got no way of deducing which host.
> 
> 
> >From: Murad Talukdar <talukdar_m@subway.com>
> >To: Tim Schwimer <tschwimer@hotmail.com>, security-basics@securityfocus.com
> >Subject: Re: Strange pings from 127.0.0.1
> >Date: Fri, 18 Jun 2004 09:43:07 +1000
> >
> >I've been getting this on my router logs saying that the tcp got dropped.
> > Source:127.0.0.1, 80, WAN - Destination:210.80.144.150, 1912, LAN -
> >'Suspicious TCP Data'
> >
> >Did you work out what it was with the pings? Not sure if it's similar or
> >not.
> >
> >Murad Talukdar
> >
> >
> >----- Original Message -----
> >From: "Tim Schwimer" <tschwimer@hotmail.com>
> >To: <security-basics@securityfocus.com>
> >Sent: Sunday, June 13, 2004 5:24 PM
> >Subject: Re: Strange pings from 127.0.0.1
> >
> >
> >> In-Reply-To: <GAEPLEDFDDGJLBGAABCNKENBCMAA.gg@stober.mailsnare.net>
> >>
> >> I started seeing the same thing on my DMZ segments this Friday afternoon
> >at about 4:00pm (figures, huh??). Anyway, I was wondering what you found 
> >out
> >about this. Any insight would be appreciated.
> >> Thanks,
> >> T
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> >> >From: "Marc" <gg@stober.mailsnare.net>
> >> >To: <security-basics@securityfocus.com>
> >> >Subject: Strange pings from 127.0.0.1
> >> >Date: Thu, 13 May 2004 23:55:35 -0400
> >> >Message-ID: <GAEPLEDFDDGJLBGAABCNKENBCMAA.gg@stober.mailsnare.net>
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> >> >
> >> >
> >> >The networked applications I am responsbile for have been performing
> >slowly.
> >> >When I tried to run Ethereal on my computer, I found some odd ICMP echo
> >> >request (ping) packets with a source IP of 127.0.01, to addresses both
> >> >within our 192.168.1.* network as well as to random Internet addresses.
> >The
> >> >source and destination Mac addresses aren't anything I can associate 
> >with
> >a
> >> >computer on our network (and they're not the real Mac address of my
> >> >computer), so I think maybe these packets are spoofed? Could this be 
> >some
> >> >sort of virus or DOS attack somewhere within our network? I've haven't
> >seen
> >> >anything quite like this mentioned online anywhere.
> >> >
> >> >Thanks, Marc
> >> >
> >> >
> >>
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Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off 
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to facilitate one-on-one interaction with one of our expert instructors. 
Attend a course taught by an expert instructor with years of in-the-field 
pen testing experience in our state of the art hacking lab. Master the skills 
of an Ethical Hacker to better assess the security of your organization. 
Visit us at: 
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