Strange results on a normal nmap-scan

Carter Bullard carter at qosient.com
Tue Jan 20 18:25:01 EST 2015


Do you have a packet capture ??  That will say a lot !!
The single line represents fragments ( 'F') notice that there aren't any port numbers.
Not sure why they are seen as fragments, but it may actually be that way on the wire ????

The other records look right, as if you're only seeing the response, and not  the SYN.

Packet capture would be great !!
Carter

 	
> On Jan 20, 2015, at 11:39 AM, elof2 at sentor.se wrote:
> 
> 
> 
> I just ran:
> # nc -nv 10.234.5.6
> (UNKNOWN) [10.200.8.4] 1234 (?) : Connection refused
> 
> 
> # nmap -sS -f 10.234.5.6
> Starting Nmap 6.00 ( http://nmap.org ) at 2015-01-20 17:15 CET
> Nmap scan report for foobar (10.234.5.6)
> Host is up (0.0023s latency).
> Not shown: 995 closed ports
> PORT     STATE SERVICE
> 22/tcp   open  ssh
> 25/tcp   open  smtp
> 53/tcp   open  domain
> 587/tcp  open  submission
> 9102/tcp open  jetdirect
> 
> Nmap done: 1 IP address (1 host up) scanned in 6.84 seconds
> 
> 
> The first netcat command resulted in:
>      StartTime      Flgs  Proto            SrcAddr  Sport Dir DstAddr  Dport  SrcPkts  DstPkts     SrcBytes     DstBytes         State
> 17:13:50.701444  e           tcp        10.123.4.5.36358   -> 10.234.5.6.1234          1        1           74           60 S_RA
> 
> Everything looks good. I sent a SYN and got a RESET-ACK back since port 1234 is closed.
> 
> 
> The nmap SYN-scan should produce lots of lines with S_, S_, S_, S_, S_ or S_RA, S_RA, S_RA, but instead I get this:
>      StartTime      Flgs  Proto            SrcAddr  Sport Dir DstAddr  Dport  SrcPkts  DstPkts     SrcBytes     DstBytes         State
> 17:15:21.343940  e          icmp        10.123.4.5.0x0008 <-> 10.234.5.6.0x9cac        1        1           56           60 ECO
> 17:15:21.344884  e  S F      tcp        10.123.4.5         ?> 10.234.5.6            3408        0       190848            0 _
> 17:15:21.345134  e           tcp         10.234.5.6.443     ?> 10.123.4.5.55213         2        0          120            0 RA_
> 17:15:21.345719  e    F     icmp        10.123.4.5.0x000d <-> 10.234.5.6               3        1          168           60 TST
> 17:15:21.347765  e           udp        10.123.4.5.37485  <-> 10.234.5.6.53            1        1           83          188 CON
> 17:15:21.352116  e           tcp         10.234.5.6.111     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.352986  e           tcp         10.234.5.6.22      -> 10.123.4.5.55213         1        1           60           56 SA_R
> 17:15:21.354002  e           tcp         10.234.5.6.1025    ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.354925  e           tcp         10.234.5.6.110     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.355825  e           tcp         10.234.5.6.53      -> 10.123.4.5.55213         1        1           60           56 SA_R
> 17:15:21.356719  e           tcp         10.234.5.6.1720    ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.357615  e           tcp         10.234.5.6.143     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.358508  e           tcp         10.234.5.6.8888    ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.359391  e           tcp         10.234.5.6.3306    ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.360296  e           tcp         10.234.5.6.5900    ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.362378  e           tcp         10.234.5.6.256     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.363184  e           tcp         10.234.5.6.445     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.364210  e           tcp         10.234.5.6.139     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.364996  e           tcp         10.234.5.6.135     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.365960  e           tcp         10.234.5.6.3389    ?> 10.123.4.5.55213         1        0           60            0 RA_
> 17:15:21.366715  e           tcp         10.234.5.6.113     ?> 10.123.4.5.55213         1        0           60            0 RA_
> 
> If I try again, now with -P0 to prevent nmap from first pinging the host, the ra results are the same. One line with thousands of packets.
> 
> 
> Why is all the SYNs aggregated into one line with a strange state of "_" and not put on 3408 separate rows with status "S_" or "S_RA"?
> 
> /Elof
> 
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