Re: SNMP Detection

Gisle, Tim,

I introduced this bug recently when I switched from bin.unpack("H") to
stdnse.tohex() because the first converts to uppercase hex and the second
to lowercase. I've fixed it in this instance by changing string literals to
lowercase, and will be revisiting the changes I made elsewhere to make sure
similar problems don't crop up.

Dan

On Tue, Mar 28, 2017 at 5:00 AM, Gisle Vanem via dev <[email protected]> wrote:

> Tim Naami wrote:
>
> > I have a target with SNMP working and I have confirmed it is responding
> using snmpwalk.
> >
> > When I use:
> >
> > nmap -sU -p 161 --script=snmp-interfaces 10.255.22.222
> >
> > I get:
> >
> > Starting Nmap 7.01 ( https://nmap.org ) at 2017-03-21 11:45 CDT
> > Nmap scan report for testuser-pc.rhsnet.org <
> http://testuser-pc.rhsnet.org> (10.255.22.222)
> > Host is up (0.00053s latency).
> > PORT STATE SERVICE
> > 161/udp open|filtered snmp
>
> I think the snmp-interface.lua script is not up-to-date. Because I
> get:
> c:\> nmap -d -sU -p 161 --script=snmp-interfaces 10.0.0.1
>
> NSE: [snmp-interfaces 10.0.0.1:161] no decoder for etype: a2
> NSE: snmp-interfaces against router (10.0.0.1:161) threw an error!
> f:\MingW32\src\inet\nmap/nselib/snmp.lua:398: attempt to index a number
> value (field '?')
> stack traceback:
>         f:\MingW32\src\inet\nmap/nselib/snmp.lua:398: in function
> 'snmp.fetchResponseValues'
>         f:\MingW32\src\inet\nmap/nselib/snmp.lua:513: in method 'getnext'
>         f:\MingW32\src\inet\nmap/nselib/snmp.lua:557: in method 'walk'
>         f:\MingW32\src\inet\nmap/scripts\snmp-interfaces.nse:430: in
> function
>       <f:\MingW32\src\inet\nmap/scripts\snmp-interfaces.nse:397>
>         (...tail calls...)
>
> Completed NSE at 09:47, 0.10s elapsed
> Nmap scan report for router (10.0.0.1)
> Host is up, received arp-response (0.00018s latency).
> Scanned at 2017-03-28 09:47:43 CET for 1s
> PORT    STATE SERVICE REASON
> 161/udp open  snmp    udp-response ttl 64
> MAC Address: 1C:BD:B9:C0:63:C6 (D-Link International)
> Final times for host: srtt: 182 rttvar: 4114  to: 100000
>
> --------
>
> But snmp-info.lua works fine.
>
> Since I know very little of Lua, I'm at loss as to what is wrong.
> But I guess the ASN1 decoder should be extended somehow.
>
> --
> --gv
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>

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