Re: Help - a possible bot

Hi Emeric

Analyzing the PC, it does not seem it's infected by Opaserv. There is no suspicious file with *scr* anywhere.

Still, like you said, wht's worrying is that the PC is responding to the port probes. Apparently traffic to port 137 is blocked - so maybe it's penetrating from another port, of from an allowed program; but the PC is responding, which means SOMETHING inside is listening, then responding (very quickly). Also, when the Internet is on-line, the explorer and svchost processes are constantly active, with I/O of 25-30 kbps. This ceases when I go offf-line.

Can anyone help? Thanks in advance

Moshe

• Original Message ----- -------------------------------- From: Emeric Miszti To: Moshe Aelion Cc: incidents @ security focus Sent: Saturday, November 16, 2002 12:59 PM Subject: Re: Help - a possible bot

Hi Moshe,

What you are seeing with the incoming port 137 UDP requests is probably the Opeserv worm. Have a look at
http://antivirus.about.com/library/weekly/aa100102a.htm.

Do you need help?

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Everyone is seeing a lot of these at the moment and if you have a look at http://isc.incidents.org/ then you will see that port 137 is far and away the most attacked port at the moment.

You can easily identify this kind of activity because the source port of normal UDP 137 traffic is 137 and the destination is port 137. With the worm activity the source port becomes something above 1024 with the destination as 137.

Looking at your fport traces, etc it doesn't look like your PC is infected by Opaserv but what is worrying is that you may be responding to the port probes, thus making you a target for further attack and that may explain the high usage on svchost!

Make sure that you are not infected by Opaserv by checking through the details provided by anti-virus companies such as http://securityresponse.symantec.com/avcenter/venc/data/w32.opaserv.worm.htm l

Since the PC has been previously hacked I would be very suspicious anyway and wouldn't rely on the firewall doing its job properly. Dameware is a total remote control package so anything could have been installed. Personally I would rebuild the PC and then install a good firewall on a clean box. That is the only way you can ever be 100% sure you are clean.

Regards

--
Emeric Miszti
UK Security Online
http://www.uksecurityonline.com

Tel No: 0870 088 5689
Fax No: 0870 706 2162

PGP Public Key available at
http://www.uksecurityonline.com/emeric.asc

On Fri, 2002-11-15 at 20:11, Moshe Aelion wrote:

> Hi everybody


hacked

> installed DameWare and was trying to work on the computer. It was


discovered

> within about 10 minutes. I then installed ZoneAlarm Pro.

>

> The problem is, I am detecting a suspicious hit/respond activity, which,

in

> my opinion, points to an active bot. Here's the evidence: when inspecting


ZA

> logs, you can see a blocked scan (coming every couple of minutes, from


key

> doesn't show anything suspicious.


phenomenon.

> I also stopped several processes and services and the phenomenon didn't


(flags:S)

> 12 FWIN,  22:07:34,   200.76.64.2:62695,    my.net.237.99:137,UDP   <--


==================================

>

> Note: the 10.0.0.1:3028 to 10.0.0.138:1723 link is the ADSL pptp.


--

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