Security Incidents: Re: Unusual volume: UDP:137 probes

[Alain Fauconnet <alain () cscoms net>]

On Fri, Oct 04, 2002 at 07:58:18AM +1200, Nick FitzGerald wrote:
> Richard.Grant () mail state ky us wrote:
> Two...
>
> You are right that Bugbear does not produce the flood of port 137 
> traffic currently being reported.  Bugbear does some spreading via 
> open or otherwise accessible shares (those writable with the 
> permissions of the user that ran the EXE) but it uses standard 
> known network resource enumeration APIs to do its work.  Opaserv (aka 
> Scrup, Scrsvr, Opasoft) aggressively scans for machines listening on
> port 137 and is the likely source of most of the increased port 137 
> activity.
>
> > ScrSvr31415.KERNEL32.dll.RegisterServiceProcess.SOFTWARE\Microsoft\Wind
> > ows\CurrentVersion\Run.Software\Microsoft\Windows\CurrentVersion\Interne
> > t
> > Settings.ScrSvr.ScrSvrOld.ProxyEnable.ProxyServer.\ScrSvr.exe.ScrSin.dat
> > .ScrSout.dat.scrupd.exe.www.opasoft.com.GET
> > http://www.opasoft.com/work/scheduler.php?ver=01&task=newzad&first=0
> > HTTP/1.1..Host: www.opasoft.com.....GET
> > http://www.opasoft.com/work/lastver HTTP/1.1..Host:
> <<snip>>
Talking of Opaserv, I have an example of a Win95 OSR2.1  box  (yes,  I
know)  which saw SCRSVR.EXE appear in its Windows folder while online.
McAfee caught it immediately so  it  didn't  have  a  chance  to  run.
However  this  box *did* have passwords set on the shares (yes, all of
them, I have checked).

These passwords were quite non-obvious so I doubt that they  could  be
found as a result of brute-force attack.

I  know that Win95 had its share of bugs regarding SMB passwords. This
one looks like a good candidate:

http://security-archive.merton.ox.ac.uk/bugtraq-200010/0228.html
NSFOCUS Security Advisory(SA2000-05)

But  then  it means that Opaserv goes beyond checking for passwordless
shares (that's all I have seen written so far). It also exploits known
vulnerabilities.

Greets,
_Alain_

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