Re: Snort SID Help 1:28039:5

[Vincent Zhen <vincent.zhen () nyu edu>]

The following code written in python fires the rule:

from scapy.all import *
p = IP(dst="8.8.8.8")/UDP(dport=53)/DNS(rd=1,qdcount=1,qd=DNSQR(qname="
www.google.pw"))
t = sr1(p)

Rules fired:
INDICATOR-COMPROMISE Suspicious .pw dns query
ET DNS Query to a *.pw domain - Likely Hostile



On Fri, Mar 11, 2016 at 11:27 AM, Vincent Zhen <vincent.zhen () nyu edu> wrote:

> Bunch of returns on the rule:
>
>
> https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=pw%20dns%20query
>
> Rule seems to suggest that someone is making a DNS request to a Palau
> domain (along UDP/53). In the payload, it looks for:
> 1. Does NOT have "[Start of Header]u[Start of Text]pw" anywhere
> 2. Query header has 24th and 48th bit set to 1. (Recursion desired and 1
> query - everything else set to 0 barring the first 2 bytes which is the DNS
> ID)
> 3. DOES have "[Start of Text]pw[NUL]" after the headers of the DNS query.
>
> Ref: http://www.networksorcery.com/enp/protocol/dns.htm
>
> Disclaimer: I'm new to snort sigs. This is what I figure it means but I'm
> in no way an authority on how they work. Please correct me if I'm wrong!
>
> On Fri, Mar 11, 2016 at 10:36 AM, Joel Esler (jesler) <jesler () cisco com>
> wrote:
>
> > Looks like it's a dns lookup for the .pw tld.  Generally speaking a place
> > of bad things.  More details would help us.
> >
> > --
> > Joel Esler
> > iPhone
> >
> > On Mar 11, 2016, at 10:25 AM, Matt Brichetto <M_Brichetto () cuinterface com>
> > wrote:
> >
> > Hello Fellow Snort Users,
> >
> >
> >
> > I get the following alert below on a LAN to LAN address. Everyone once
> > and awhile we get this, but there seems to be no info on the rule. Has this
> > rule been deprecated or something along those lines. I really don’t know
> > how to troubleshoot this or if it is a false positive.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > EVENT # :
> >
> > 172511
> >
> > EVENTLOG :
> >
> > Application
> >
> > *EVENT TYPE :*
> >
> > *WARNING (2)*
> >
> > SOURCE :
> >
> > snort
> >
> > EVENT ID :
> >
> > 1
> >
> > TIME :
> >
> > 3/11/2016 9:25:55 AM
> >
> > MESSAGE :
> >
> > [1:28039:5] INDICATOR-COMPROMISE Suspicious .pw dns query
> > [Classification: A Network Trojan was Detected] [Priority: 1] {UDP}
> > 192.168.22.16:17159 -> 192.168.22.4:53
> >
> >
> >
> >
> >
> > Thanks,
> >
> >
> >
> > *Matt Brichetto*
> > Network Administrator
> >
> >
> >
> >
> >
> >   ­­
> >
> >
> > ------------------------------------------------------------------------------
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>
>
>
> --
> Vincent Zhen
> Network Security Analyst, NYU Technology Security Services
> New York University
> 726 Broadway, New York, NY 10003



-- 
Vincent Zhen
Network Security Analyst, NYU Technology Security Services
New York University
726 Broadway, New York, NY 10003

------------------------------------------------------------------------------
Transform Data into Opportunity.
Accelerate data analysis in your applications with
Intel Data Analytics Acceleration Library.
Click to learn more.
http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140

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