How to tell if a firewall alert is suspicious or not

On Thu, 15 Sep 2005 15:44:45 +0100, Mike wrote:

Snip pointless list

Without knowing what you were doing at the time, what applications you
need to run, how your network is configured, if you indeed have a
network and a host of other detail, there is no way of knowing. There is
no 'correct' answer.

Sorry about not being specific. I already pared the list down to those
event which occur WITHOUT the users' explicit action. For example, I
removed any request to/from the NNTP software which occur while using it.
Likewise with POP3/SMTP clients, explicit actions from HTTP clients, etc.

The Sygate Personal Firewall software has the ability to "remember" a
decision so the user, if they knew which to ignore, would not see those
which make it into the innocuous list. That is mainly why I ask.

Example:-
Generic Host Process for Win32 Services (svchost.exe)
is trying to connect to time.windows.com [207.46.130.100
using remote port 123 (NTP - Network Time Protocol).
Do you want to allow this program to access the network?

Again, I should have noted, I never explicitly told the Windows XP machine
to synchronize the time so that is why this unasked for request made it
onto the posted listing. Said another way, if I KNEW I had explicitly asked
WinXP to synchronize the time, I would have removed that request from the
list (by telling Sygate Personal Firewall to simply accept all of those
requests in the future).

Ditch the stupid software and get a router.

Isn't the D-Link wired and wireless box connected to the DSL modem a
"router"?

On Thu, 15 Sep 2005 11:02:57 -0400, null wrote:

However, to tell him to trash the software firewall and rely strictly on
a router is simply bad advice.

I'm confused whether the D-Link wired and wireless box I have connected to
the DSL modem is considered the "router" you bespeak of. Is it?

On Thu, 15 Sep 2005 18:11:47 GMT, nutso fasst wrote:

NDIS messages from 192.168.x.x suggest you have a wireless NAT router and
your firewall is responding to messages from it. (Surely you are behind some
kind of NAT, ICS perhaps.) If you're not using a wireless network, disable
wireless configuration service.

I am using a wireless D-Link (is that the router you bespeak of)?

You're suggesting the compilation of what could be an ever-expanding
database of mostly-irrelevant details. Seems to me time would be better
spent becoming more of an expert.

I do run http://www.dnsstuff.com checks on all requests that the Sygate
Personal Firewall pops up before putting the messages on the list of
suspicious items. Also I don't put on the list messages which pop up from
KNOWN events. For example, when I start the NNTP client, a message pops up
which I tell the Sygate Personal Firewall program to accept forever (so
that message only pops up once). Likewise with the web browser, email
client, Microsoft Anti-Spyware update program, Windows Updater, Real Audio
client, etc.

I only posted what I considered the unasked for messages (not the obvious
ones).

On Thu, 15 Sep 2005 07:56:07 -0400, Karl Levinson, mvp wrote:

There are ways you can research these things...

Generally I do two obvious things each time I get a NEW message.
1. I run a reverse-IP address lookup at www.dnsstuff.com
2. I search Google Groups for the exact message (often I find others have
the exact same question, with the exact same message, and IP address).

Should I do more?
I'm hoping others can find THIS THREAD, for example, when they get the
messages I just posted and therefore they'd get the advice we all so
desperately need.

Where would YOU go when you received any one of the messages previously
posted when you didn't explicitly ask for that IP address to connect to
you?



however, you will get so many of these alerts, and it is so
fruitless to research them all, that I strongly recommend you consider
a firewall configuration that does not alert you all the time with
these things.

THAT's THE WHOLE POINT OF THIS THREAD!
With Sygate Personal Firewall (and I suspect all software firewalls), you
can tell the program to silently ignore and simply LOG all these
connections! My question was really WHICH OF THESE WOULD YOU IGNORE?


Having a firewall ask the user to make decisions is a security accident
waiting to happen, and is also a significant consumption of your time.

Is there any other choice?
These requests were made to my machine and I must respond to them.
Of course, I could simply say "Accept All Requests" but that would be
folly. The question really becomes two questions:
1. Which of these common requests is truly something to ignore
2. Of those which aren't ignorable, HOW DO NOVICES FIGURE THEM OUT?

If and when you do want to research these things, you should look up what
the remote IP address is

I generally use http://www.dnsstuff.com but your suggestion of adding for
www.nwtools.com or www.netsol.com is valid. I did that, for example, with
the DHCP server request. But, that really only tells me who owns the
machine. It doesn't tell me WHY they would be contacting me. (Remember,
that server only contacted me once and I have been using this same setup
for years). So, why, all of a sudden, would a machine which purports to be
a DNS server, be contacting me?

It's also useful to know what the protocol [e.g. TCP] and remote port number
is... the firewall alert below didn't seem to tell you, which is really
dumb.

In defence of the Sygate Personal Firewall, there is a DETAILS button which
spits out a huge amount of cryptic (to a novice) information about
something called a "packet" so the remote port MIGHT be in that listing.

A really smart firewall would let you inspect the TCP flags and contents of
the incoming packet, but I guess that's too much to ask.

I could post the DETAILED information if it would help (caution, it's
cryptic at best).

On Thu, 15 Sep 2005 15:48:26 +0100, Mike wrote:

Novices do not have the knowledge as you so patently demonstrate.
You need a hardware firewall like the ones built into Zyxel routers etc.

Is the D-Link wireless/wired box connected to the DSL modem set up in the
default configuration sufficient?

Or is there something ELSE I should purchase to get this "hardware
firewall"?

If you had a router you would not have seen it or been startled plus you
would have been protected.

I've been using this setup for more than a year and this is the FIRST time
that particular server contacted me (for whatever reason). That is what
startled me and made me suspicious.

On Thu, 15 Sep 2005 12:51:41 GMT, Duane Arnold wrote:

That's for you to determine by using a link like to one below and entering
the IP into the WhoIs search box and finding out of the IP is
dubious or not.

That's only HALF the answer.
All it tells you is WHO made the request.
That doesn't tell you if the request is valid.

For example, the posted DNS address has NOT contacted me ever in the more
than a year that my DSL to D-LINK setup has been in existance. So, WHY
should a machine which purports to be a DNS machine all of a sudden contact
me today?

On the other hand, many of the requests happen every day all day.
That STILL doesn't make them innocuous; it just makes them "probably" not
suspicious. That would include, for example, the NDIS User mode I/O Driver,
the NDIS Filter Intermeidate Driver, the Generic Host Process for Win32
Services, etc. All I'm asking is for these events, none of which are
explicitly user initiated, is it reasonable to tell the Sygate Personal
Firewall to ACCEPT all these requests without complaint?

On Thu, 15 Sep 2005 18:14:23 -0300, alfranze wrote:

Firefox is a browser of the Mozilla.
then, you can do the command line: tracert 206.13.28.12 and to know
what/where this IP (or any) is, if it really works....

Since NOBODY has mentioned the problem that this is only HALF the story, I
wonder if I understand this correctly.

Knowing the machine "name" and "owner" is only HALF the story (isn't it)?
The other half is for what PURPOSE did the machine contact my machine.

For example, when Adobe Acrobat 6.0 (Acrobat.exe) [206.13.31.12] contacts
me on local port 1880 (VSAT-CONTROL - Gilat VSAT Control), I can find the
name of the machine contacting me from www.dnsstuff.com as
"dns1.scrmca.sbcglobal.net" ... but that does not tell me anything about
WHY this SBCGlobal DNS server would be contacting Adobe Acrobat on port
1880 (whatever that port is for).

Knowing ONLY the name of the server contacting you, would YOU want to allow
this program to access the network?

On Thu, 15 Sep 2005 19:25:21 -0600, Bruce Chambers wrote:

Sygate Personal Firewall:
Firefox (firefox.exe) is being contacted from a remote machine
[206.13.28.12] using local port 1258 (OPENNL - Open Network Library).
Do you want to allow this program to access the network?

Do you have another computer on your internal network with that
specific IP address? Is that computer allowed to connect to the
Internet via your computer?

Of course not!

If I had another machine on the same tiny home network with that IP address
(which would be highly unlikely in a 192.168.0.XXX network), then I would
NOT have posted that specific request in the list above as it would have
been an obvious innocuous request.

Again, knowing the machine name & owner is only HALF the story. Actually,
it's only 1/3 the story as the following is important:
1. WHO is the owner of that machine?
2. WHAT is the purpose of the port being used?
3. WHY is that machine contacting me?

Is this information available somewhere?

Note that the WHO part is trivial to obtain, e.g., we can obtain that from:
http://www.dnsstuff.com
http://www.nwtools.com
http://www.netsol.com
http://remote.12dt.com/rns
http://www.zoneedit.com/lookup.html
etc.; but that doesn't tell us WHAT or WHY.


The WHAT part, albeit often highly technical, is not too very difficult to
obtain, e.g., we can use any of the following which describe the ports:
http://www.bekkoame.ne.jp/~s_ita/por...1200-1299.html
http://www.seifried.org/security/ports/1000/1258.html
http://www.iana.org/assignments/port-numbers
http://www.sonomawireless.com/~ports/port1200-1299.html
http://www.auditmypc.com/freescan/re...m/portlist.asp
etc.; but that doesn't tell us WHY they contacted us.

The WHY part is the key question.

For example, WHY would dns1.snfcca.sbcglobal.net contact my machine on tcp
tdp/udp port 1258 named the Open Network Library?

The question becomes:
1. HOW do users learn MORE about the PURPOSE of this OPEN NETWORK LIBRARY?
2. HOW do we obtain possible REASONS for a machine contacting us on this
port?

That advice was the purpose of the original question.

On 15 Sep 2005 10:10:51 +0200, Volker Birk wrote:

Firefox (firefox.exe) is being contacted from a remote machine
[206.13.28.12] using local port 1258 (OPENNL - Open Network Library).
Do you want to allow this program to access the network?
How can I tell if this is suspicious or not?

You can't. This is, why such messages are nonsense. BTW, they're useless,
too, because also Sygate cannot prevent "phoning home" from malicious
programs anyway, as my simple POC here shows:

http://www.dingens.org/breakout.c

Unfortunately, I don't know what a POC (point of contact?) is nor do I have
a c compiler.

What does the breakout.c program do for us? Does it slip past the Sygate
Personal Firewall somehow secretly and silently?

I think there are 3 parts to the problem, one of which is trival, the other
of which is technical, and the third of which is the crux of the matter:

1. WHO is it that is contacting us (all agree this is trivial to obtain but
nearly meaningless in many cases as it doesn't tell us WHAT they are doing
when they contact us or WHY they are doing it).

2. WHAT the machine is doing when it contacts us (I suspect this is
explained somewhere on the Internet based on the port being contacted, but
so far all I've found is the posted listings of a NAME and quick
DESCRIPTION of the port used). This is INCOMPLETE information as merely
knowing the name of a protocol doesn't always help to understand WHAT is
occurring. Plus, I routinely DENY all these requests and my machine seems
to work fine so what is it that it is doing anyway?

3. WHY would the machine contact us on the specified port. I believe this
is the crux of the question. My question to you experts is to ask if there
is a good web site which would explain WHY any particular machine would be
contacting us on any particular port. If we knew WHY, we could then decide
whether to allow this connection or now.

For example, WHY would Adobe Acrobat 6.0 (Acrobat.exe) be contacted from an
SBCGlobal DNS machine [206.13.31.12] using local port 1880 (VSAT-CONTROL -
Gilat VSAT Control)?

What could it possibly want?
Why doesn't anything bad happen when I deny the request?

On 15 Sep 2005 19:14:08 +0200, Volker Birk wrote:

It's OK, that not everybody is a networking expert. A good security solution
has to work _without_ asking the user.

For we novices who still desire basic firewall protection, it would be nice
to refer to a list of known generally non-dangerous requests to accept.

Why not using the Windows-Firewall and not having such problems?

Since the remote machine is gonna try to contact us anyway, wouldn't we
have the same three problems no matter which personal firewall solution we
used?

For example, if I used Windows XP Firewall, or ZoneAlarm (
http://snipurl.com/6ohg ) or Kerio Personal Firewall (
http://www.kerio.com/kpf_download.html ) or Sygate Personal Firewall (
http://smb.sygate.com/free/spf_download.php ) or Outpost Firewall (
http://www.agnitum.com/products/outpost ) or whatever, WOULDN'T the
offending machine STILL try to contact my machine?

And then, if it did, wouldn't we STILL have the THREE QUESTIONS:
1. Who is trying to contact us?
2. On what port are they trying to contact us?
3. Why are they trying to contact us?

This seems, to me, to be such a common need for virtually every one of the
millions of computer users out there, that the ANSWER to these three
questions SHOULD be somewhere very easy to locate for we novice users?

I can't believe there is a single person out there on the Internet who
doesn't have this very same problem. That's why it's so frustrating to me
to not be able to find the all-important WHY information so desperately
needed by millions of us users.

GS

Gerard Schroeder wrote:
I thank you for your detailed suggestions summarized below as:
1. There exists innocent common connections reported by the firewall

Yes.

Regarding the first interesting comment above:
- Is there a site where all the common innocent connections are listed?

I don't know one. And I think, this will not be possible. There are
too many possibilities for these. Why using a "Personal Firewall" at all,
which is showing useless Popups?

Regarding looking up the NAME of the IP address:
- WHY would my DNS provider suddently connect (this does not happen often)?

There may be many reasons for this.

Regarding the content of the incoming packets:
- Sygate Personal Firewall 5.6 provides a Yes/No/Details response
- The DETAILS button gives more information (cryptic to me, a novice).
- Again I wonder if there is a list of known non-dangerous contacts.

The point is, that this is a b0rken concept to ask the only person,
who for sure does not know what to do here - you, the user.

It's OK, that not everybody is a networking expert. A good security solution
has to work _without_ asking the user.

For we novices who still desire basic firewall protection, it would be nice
to refer to a list of known generally non-dangerous requests to accept.

Why not using the Windows-Firewall and not having such problems?

Yours,
VB.

On 15 Sep 2005 19:09:09 +0200, Volker Birk wrote:

null wrote:
However, to tell him to trash the software firewall and rely strictly on
a router is simply bad advice.

No. It's a very good advice. Also he could use the Windows-Firewall.

Unless the router performs stateful packet inspection and is highly
configurable, etc., etc., etc., then the router alone will not be
providing sufficient protection.

The "Personal Firewalls" we tested all were terribly incompetently
implemented. I doubt, that with a "Personal Firewall" he will be secure
in any way.

His use of a software firewall is not unreasonable, and your advice to
get rid of it is unwise.

The opposite is true.

If Adobe Acrobat 6.0 (Acrobat.exe) is going to be contacted from a remote
machine [206.13.31.12] using local port 1880 (VSAT-CONTROL - Gilat VSAT
Control), what would Windows Firewall do differently from what Sygate,
ZoneAlarm, Kerio, Outpost, etc. would do?

"Gerard Schroeder" wrote in message
...

I am using a wireless D-Link (is that the router you bespeak of)?

Not specifically, but it qualifies. I'd OK the NDIS messages.

I only posted what I considered the unasked for messages (not the obvious
ones).

Unasked for... You weren't visiting a secure web page when you got the HTTPS
message? Weren't looking at a PDF when the DNS server tried to contact
Acrobat? That would be odd indeed. As for some of the others, is it possible
a web page you were visiting pulled an advertisement or graphic from a
different address? Have you looked at the relevant transactions in context
in the firewall logs? Do you understand that local ports 1024-5000 are
typically ones YOUR system uses to connect to a remote system? And that once
a connection is made, the remote system communicates FROM the destination
port TO the port your system has connected from?

Next time you get a prompt referring to any of those local ports, try
opening a command prompt and typing 'netstat -a' and see if the port's
currently connected to something. I suspect the references to 'Open Network
Library' and 'NetBill Authorization Server' are bogus (pulled from the list
of 'registered ports'). But then, I'm no expert.

Ask on the Sygate forum.

nf

"null" wrote in message
...

However, to expect the average user to understand what the different
protocols are, what they do, and what ports are used for what, is a bit
over the top. Like you hinted at, the firewall responses to incoming and
outgoing packets should be as automated as possible for the average user.

I don't expect the user to know that. But I expect the firewall to include
that information in the error message, for situations like this one where
the user copies and pastes the error message to their firewall support or to
a newsgroup for assistance. Not having those details really cripples
whoever is trying to help the user. If necessary, the vendor can hide this
information under a "Details" button on the message, and put them into the
log file for posterity.

"Gerard Schroeder" wrote in message
...

Where would YOU go when you received any one of the messages previously
posted when you didn't explicitly ask for that IP address to connect to
you?

I do the same things I suggested in my post.

THAT's THE WHOLE POINT OF THIS THREAD!
With Sygate Personal Firewall (and I suspect all software firewalls), you
can tell the program to silently ignore and simply LOG all these
connections! My question was really WHICH OF THESE WOULD YOU IGNORE?

I think the best firewall configuration is one that doesn't give you any
popups whatsoever. Corporate firewalls don't give the firewall
administrator popups and ask him or her questions. They just work. The
same thing is true of hardware firewalls used in homes. Firewalls should
have just two situations: packets it knows are bad and it blocks without
question, and everything else that it lets through.

Having a firewall ask the user to make decisions is a security accident
waiting to happen, and is also a significant consumption of your time.

Is there any other choice?

Yes... I don't have the latest version of Sygate, but I believe most
software firewalls have a configuration choice that does not cause any
popups. If Sygate doesn't, there's also www.kerio.com, www.zonealarm.com,
both of which are free. If you are already protected by a hardware
firewall, you may not really totally need that software firewall.

1. Which of these common requests is truly something to ignore

All of them.

machine. It doesn't tell me WHY they would be contacting me. (Remember,

The problem is all you've got is what the firewall tells you, and it hasn't
told you everything you need to know. Very often, you will not be able to
100% determine the cause. You'll have to make a best guess, go with a gut
feeling, and move on. Even professionals who monitor computer networks for
intrusions do this as well.

Another possibly strategy would be to deny any packets you have questions
about. If something breaks, then you know it was probably something you
needed to allow. This is also the safest strategy.

that server only contacted me once and I have been using this same setup
for years). So, why, all of a sudden, would a machine which purports to be
a DNS server, be contacting me?

I believe it is more likely that this was a reply to a connection your
computer made. The reply took too long to come back, and your firewall
stopped watching that connection, was surprised when the reply came back and
considered it a new connection. DNS servers should never be contacting you.
This situation can happen when you look up the IP address for a host name
where the DNS server is troubled or down and does not respond, and the
request times out 45 seconds or more later. It's happened to me.

In defence of the Sygate Personal Firewall, there is a DETAILS button
which
spits out a huge amount of cryptic (to a novice) information about
something called a "packet" so the remote port MIGHT be in that listing.

Ah, that might help us a little. But I'm still leaning towards ignoring
this one, moving on, and pursuing a silent firewall configuration.

I could post the DETAILED information if it would help (caution, it's
cryptic at best).

Sure, go ahead.

"Gerard Schroeder" wrote in message
...

So, why, all of a sudden, would my DNS server be contacting me, out of the
blue. And, why, does my network still (apparently) work even though I said
NO to the request?

See my other post. More likely, this was a reply to your computer, but the
reply took so long, your firewall wrongly considers this a new inbound
connection. DNS especially does this due to having timeout values that are
greater than the timeout values in many stateful firewalls.

What would be nice is for users to post (and for experts to doublecheck)
what they consider to be innocuous requests uninitiated by them which
appear in their yes/no request list from Sygate.

I am willing to START that list of what appears to be common innocuous
requests (for expert review).

It's not really that easy. If it was, someone would have done it already.
One problem is that each firewall reports things in different ways. Another
problem is that some Firefox traffic is good, and some might not be so good.
These sorts of things are very variable and conditional. However, you can
find some informative resources by searching www.google.com for firewall-faq
and also search for ids-faq. In particular, there are some good IDS FAQs on
Robert Graham's web site [google says it's at
http://www.robertgraham.com/pubs/net...detection.html but I
can't get to that web site currently] and especially this, I strongly
recommend reading this:

http://www.myne****chman.com/kb/res-falsepos.htm

By the way, you may want to sign up with a free service like
www.myne****chman.com or www.dshield.org Those sites automatically report
hacking attempts blocked in your firewall to the ISPs responsible, and they
also let you see useful relevant information from other people's firewall
logs, which helps you determine whether something is just hitting you or is
hitting a lot of other people. You can't get that information any other
way.