RE: What is up with i.gtld-servers.net?

From: Mike Batchelor (mikebatat_private)
Date: Mon Jun 18 2001 - 12:19:05 PDT

  • Next message: Rafael Coninck Teigao: "Strange stuff on logs, followed by reboot"

    > I first noticed odd probes not too long after h.gtld-servers.net went
    > online (yes, I meant H and not I). I use the ARIS security focus stuff
    > as a sanity check (i.e. if I'm the only one seeing something, not a big
    > deal).
    
    Nothing is up with I.gtld-servers.net.  Just because it shows up in a snort
    log, or on ARIS, doesn't mean it's a probe, and doesn't even mean it's
    suspicious.  Check out the other GTLD or root servers.  I bet most of them
    have just as many "reports" on ARIS.
    
    The most likely explanation is that Snort "lost state" on your outgoing DNS
    queries, because I.gtld-servers.net is taking too long to answer.  So it
    flagged the "unknown" UDP replies as "misc traceroute" traffic.  You need to
    read IDS logs with a jaundiced eye, or you'll go crazy chasing down false
    positives.
    
    >
    > I see listed "Total Incidents: 6372, System Cumulative Incidents: 6372,
    > Other Affected ARIS Users: 32" for 192.36.144.133. Hey, a little bit of
    > this could be some kid out of school using nmap to spoof, except that
    > they are valid (sort of) queries, and they just look ODD. Below is a
    > snort sample (yes, it's always to port 8708, which is indeed bound to
    > named):
    
    "Valid (sort of) queries"?  Being valid is like being pregnant, there is no
    "sort-of".  What is "looks ODD" about these packets?  They look like normal
    DNS replies to me.
    
    >
    > [**] IDS03 - MISC-Traceroute UDP [**]
    > 06/15-01:38:06.209014 0:20:6F:5:6:3B -> 0:20:78:10:59:1D type:0x800
    > len:0x9A
    > 192.36.144.133:53 -> 206.111.213.146:8708 UDP TTL:1 TOS:0x0 ID:18065
    > Len: 120
    > 57 F0 80 00 00 01 00 00 00 02 00 02 03 52 53 31  W............RS1
    > 04 41 52 49 4E 03 4E 45 54 00 00 01 00 01 C0 10  .ARIN.NET.......
    > 00 02 00 01 00 02 A3 00 00 0D 03 52 49 50 03 50  ...........RIP.P
    > 53 47 03 43 4F 4D 00 C0 10 00 02 00 01 00 02 A3  SG.COM..........
    > 00 00 0D 03 52 53 30 06 4E 45 54 53 4F 4C C0 32  ....RS0.NETSOL.2
    > C0 2A 00 01 00 01 00 02 A3 00 00 04 93 1C 00 27  .*.............'
    > C0 43 00 01 00 01 00 02 A3 00 00 04 D8 A8 E0 CE  .C..............
    >
    > [**] IDS03 - MISC-Traceroute UDP [**]
    > 06/15-08:12:23.098548 0:20:6F:5:6:3B -> 0:20:78:10:59:1D type:0x800
    > len:0x20F
    > 192.36.144.133:53 -> 206.111.213.146:8708 UDP TTL:1 TOS:0x0 ID:18918
    > Len: 493
    > 8A 48 80 00 00 01 00 01 00 0C 00 0C 04 44 4E 53  .H...........DNS
    > 34 02 43 50 04 4D 53 46 54 03 4E 45 54 00 00 01  4.CP.MSFT.NET...
    > 00 01 C0 0C 00 01 00 01 00 02 A3 00 00 04 CF 2E  ................
    > 8A 0B C0 14 00 02 00 01 00 02 A3 00 00 07 04 44  ...............D
    > 4E 53 32 C0 11 C0 14 00 02 00 01 00 02 A3 00 00  NS2.............
    > 07 04 44 4E 53 31 C0 11 C0 14 00 02 00 01 00 02  ..DNS1..........
    > A3 00 00 0A 04 44 4E 53 31 02 54 4B C0 14 C0 14  .....DNS1.TK....
    > 00 02 00 01 00 02 A3 00 00 07 04 44 4E 53 32 C0  ...........DNS2.
    > 69 C0 14 00 02 00 01 00 02 A3 00 00 0A 04 44 4E  i.............DN
    > 53 33 02 55 4B C0 14 C0 14 00 02 00 01 00 02 A3  S3.UK...........
    > 00 00 07 04 44 4E 53 34 C0 92 C0 14 00 02 00 01  ....DNS4........
    > 00 02 A3 00 00 0A 04 44 4E 53 33 02 4A 50 C0 14  .......DNS3.JP..
    > C0 14 00 02 00 01 00 02 A3 00 00 07 04 44 4E 53  .............DNS
    > 34 C0 BB C0 14 00 02 00 01 00 02 A3 00 00 0A 04  4...............
    > 44 4E 53 31 02 44 43 C0 14 C0 14 00 02 00 01 00  DNS1.DC.........
    > 02 A3 00 00 07 04 44 4E 53 32 C0 E4 C0 14 00 02  ......DNS2......
    > 00 01 00 02 A3 00 00 0A 04 44 4E 53 31 02 53 4A  .........DNS1.SJ
    > C0 14 C0 14 00 02 00 01 00 02 A3 00 00 07 04 44  ...............D
    > 4E 53 32 C1 0D C0 3E 00 01 00 01 00 02 A3 00 00  NS2...>.........
    > 04 CF 2E 8A 15 C0 51 00 01 00 01 00 02 A3 00 00  ......Q.........
    > 04 CF 2E 8A 14 C0 64 00 01 00 01 00 02 A3 00 00  ......d.........
    > 04 CF 2E E8 25 C0 7A 00 01 00 01 00 02 A3 00 00  ....%.z.........
    > 04 CF 2E E8 26 C0 8D 00 01 00 01 00 02 A3 00 00  ....&...........
    > 04 D5 C7 90 97 C0 A3 00 01 00 01 00 02 A3 00 00  ................
    > 04 D5 C7 90 98 C0 B6 00 01 00 01 00 02 A3 00 00  ................
    > 04 CF 2E 48 7B C0 CC 00 01 00 01 00 02 A3 00 00  ...H{...........
    > 04 CF 2E 48 7C C0 DF 00 01 00 01 00 02 A3 00 00  ...H|...........
    > 04 CF 44 80 97 C0 F5 00 01 00 01 00 02 A3 00 00  ..D.............
    > 04 CF 44 80 98 C1 08 00 01 00 01 00 02 A3 00 00  ..D.............
    > 04 CF 2E 61 0B C1 1E 00 01 00 01 00 02 A3 00 00  ...a............
    > 04 CF 2E 61 0C                                   ...a.
    >
    > Any suggestions? I'm just plain baffled. Oh, and I now have tcpdump
    > running, just waiting for any further stuff from it. Hey, if you can't
    > trust the (sub)root servers, who can you trust?
    >
    > --
    > When explaining a command, or language feature, or hardware widget,
    > first describe the problem it is designed to solve.
    >               David Martin
    >
    



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