full-disclosure - Re: SNMP Reflected Denial Of Service

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Date: Sun, 02 Sep 2012 18:03:05 -0400
From: Full Disclosure <full.disclosure@...dex.ru>
To: Anestis Bechtsoudis <bechtsoudis.a@...il.com>
Cc: "full-disclosure@...ts.grok.org.uk" <full-disclosure@...ts.grok.org.uk>
Subject: Re: SNMP Reflected Denial Of Service - PoC

Actually, if you test it against windows snmpd or a lot of Cable modems out there, the getbulk request causes a 1500 byte packet reply.
You probably tested it against linux snmpd or cisco, which in that case , yes, it returns null. 

31.08.2012, 09:31, "Anestis Bechtsoudis" <bechtsoudis.a@...il.com>:
> On 8/30/12 8:13 PM, Full Disclosure wrote:
>
>>  Hi list,
>>
>>  I am releasing this code due to the fact that my dev server got hacked and people have been using it in the wild for bad things.
>>
>>  Network admins should patch their networks appropriately by rejecting snmp connections from unwanted IPs.
>
> The quoted code is actually nothing more than a regular threaded UDP
> flood DoS tool, both SNMP spoofed requests and responses are equally 65
> bytes (no reflection). Make a simple network capture for verification.
>
> The payload is a mis-used .1.3.6.1 getBulk SNMP request resulting in a
> null value response.
>
> A sample perl script with the biggest reflection factor per transaction
> achieved on Cisco devices is available here [1] (Amplification = 84
> bytes request / 1480 bytes response).
>
> For more information about SNMP reflection DoS you may refer to this
> link [2].
>
> The quoted code reminds me an old implementation on the same concept [3].
>
> [1] http://pastebin.com/M9cJs89h
> [2] https://bechtsoudis.com/hacking/snmp-reflected-denial-of-service/
> [3] http://packetstormsecurity.org/DoS/snmpdos.c
>
> -A
>
> --
> #----------------------------------------------#
> | Anestis Bechtsoudis                          |
> |                                              |
> | Network Operation Center,                    |
> | Laboratory for Computing (LabCom),           |
> | Dept. of Computer Engineering & Informatics, |
> | University of Patras, Greece                 |
> |----------------------------------------------|
> | Public Key: http://bit.ly/Q2f5gW             |
> | Website: https://bechtsoudis.com             |
> #----------------------------------------------#

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