l0pht develops Sniffer Sniffer 97
An anonymous reader has written in to say that l0pht has released a sniffer detector called AntiSniff.
You can use it to determine if someone is sniffing around your network.
There's already rumors of sniffer-sniffer-proof-sniffer already for
those of you who already knew what I knew I thought you knew I knew.
Old news... (Score:1)
Cool, but... (Score:1)
- A.P.
--
"One World, One Web, One Program" - Microsoft Promotional Ad
Re:Not again.. (Score:2)
Yes, but... (Score:1)
If someone NEW tries using a name like that, then no slack.
Re:tracing sniffers with corrupt ARP entries (Score:1)
-Peter
Re:Network General, anyone? (Score:1)
That's just one of many tricks; others involve talking to sniffer candidates to see how the cards respond to packets differently when in promiscuous mode.
How to get your software posted on slashdot (Score:1)
Re:So what (Score:2)
what anti-sniff isn't... (Score:2)
Anti-sniff was made mainly to try to detect sniffing on machines that are known to exist and must still listen on the network (like servers).
It will send bogus IP and others weird things to check if it slow down the machine, as well as a few others tricks.
Depending of the bandwidth to the machine, the speed of the machine and the intelligence of the sniffer that may not work.
However it is a little extra in a sysadmin toolbox, it's not perfect but may help.
Re:Linux Sniffer? (Score:1)
Re:Linux Sniffer? (Score:1)
Thankyou for moderators, slashdot (Score:1)
I guess there aren't enough moderators to keep all of the "I don't know anything about this, and I can't think of how it could work, therefore it must not work" down to -1.
Re:Linux Sniffer? (Score:1)
The Ethereal site is here. [zing.org] (I shan't say what the best sniffer is, as I'm not exactly a neutral observer.... :-))
(Note also that Ethereal isn't Linux-only.)
Re:Promiscuous mode in 98/NT? (Score:1)
If your system has a driver that lets you get at raw packets (the moral equivalent of raw DLPI access on Solaris, SOCK_PACKET or packet filter access on Linux, BPF access on BSD, etc.), the driver could provide a way to enable or disable promiscuous mode on cards that support it, read and write raw packets, etc..
Unfortunately, NT either doesn't come with such a driver by default, or doesn't document it (NT Server comes, I think, with Network Monitor, which includes such a driver, although the version that comes with NT is claimed not to support promiscuous mode; you need the version that comes with System Management Server to get that).
The Microsoft Developer Network stuff comes with sample driver and userland code to do that, at least on NT, and PCAUSA [pcausa.com] sells the Win32 NDIS Framework [pcausa.com], which includes a driver and a userland library to let you do that on W9x and WNT (complete with a BPF interpreter in the driver, so you can do BPF-style packet filtering when capturing).
I've not used either of them, so I can't say one way or the other how well they work.
Details? (Score:2)
Re:Defeat sniffer easily ... (Score:1)
The design of AntiSniff is to detect intruders running sniffers on your network.
-weld
Defeat sniffer easily ... (Score:1)
Re:So what (Score:1)
Re:Not again.. (Score:1)
Coudn't you just use ARP? (Score:1)
Or has this been tried and found not to work?
Re:So what (Score:1)
hrm (Score:1)
automotive electronics has this beat already (Score:1)
AntiSniff timeline... (Score:1)
08/15/1999 - AntiSniff mentioned on CryptoGram [counterpane.com]
08/17/1999 - Submitted to Slashdot by anonymous reader [slashdot.org]
Re:Not anything new (Score:1)
Not anything new (Score:2)
Re:anti sniffer (Score:1)
The third method takes response time data from hosts before and during a flood of packets with bogus MAC addresses. This is the core detection routine, and actually comprises three different timing attacks.
There are multiple techniques to invalidate these tests; however, the intent of the tool is to detect *unauthorized* sniffing on a segment, and a number of the best anti-antisniffer techniques imply control of the surrounding network infrastructure...
It's an arms race, but isn't it always? The tool has its place.
-- Cerebus
Re:I knew that... (Score:1)
Maybe?
...
Re:like in "the Big Hit" (Score:1)
But yeah, after a certain point you'll hafta use exponents:
trace-buster^3
trace-buster^27
There is alreadi an anti-antisniffer sniffer (Score:2)
The technique used by this anti-sniffer is to check for machines lagging in replys due to the small amount of time it takes the sniffer to write everything on disk.
It's fairly easy to modify the current sniffers to drop the promiscuous mode once they detect the huge amount of packets sent by the AntiSniffer
My $.02
Yeah, it's just you (Score:1)
This works great (Score:1)
Re:There is alreadi an anti-antisniffer sniffer (Score:1)
Not again.. (Score:1)
Re:Linux Sniffer? (Score:1)
Re:Sniffing the sniffer? (Score:1)
I know that an ethernet aui connection can be wired so that it only receives. I don't think you can do that with a 10BaseT connection (link integrity won't work and may take the port down).
Can't compile Ethereal (Score:1)
Can compile now (Score:1)
Sniffing the sniffer? (Score:2)
The one that is not relies on the fact that if you beat the hell out of a system in promiscuous mode, it'll slow down, badly. Basically, it pings the shit out of the system while adding a bunch of network traffic destined to somewhere else. Then it measures latency on the pings. If that latency stays about the same, then the system you are pinging is probably ignoring all that other traffic at the hardware layer. If it goes up by a good amount, then that extra traffic may be getting through, passing to the software, thus slowing the system down enough to detect.
An actual sniffer device has none of these issues. Hell, a lot of them don't even HAVE an IP address. You stick it on the network, and hear pretty much what you want to hear. Transmit from any IP you want. It's just a matter of forming the packet correctly. If the system doesn't send out anything at all, there's no way to detect it, short of mucking about with resistances on the line or some EE stuff I know nothing of.
---
Network General, anyone? (Score:1)
Guess I'll have to check this out...
Re:Network General, anyone? (Score:1)
Then again, that wouldn't explain why the NT boxes have two interfaces - one for monitoring and one for transport...
Eh, I liked the DOS version more than the NT version anyway.
Re:Impossible product. (Score:1)
AntiSniff on Bugtraq... Go to the source. (Score:3)
Some very interesting discussion about AntiSniff took place on the bugtraq mailing list; here are the relevant threads (and yes, there is already an AntiAntiSniff Sniffer :) :
07/25/1999 - People start trying to figure out workarounds [securityfocus.com]
07/25/1999 - Another discussion thread on AntiSniff and how it works [securityfocus.com].
07/25/1999 - The AntiAntiSniffer Sniffer is released: "All Hail The AntiAntiSniffer Sniffer!" [securityfocus.com]
--
Re:Other Ways to Detect Sniffers (Score:1)
However, most crackers have to get into your network remotely. They usually find their way into a general-purpose machine. For practical reasons, it may not be possible for him/her to put the NIC into 100% receive-only mode. That is the kind of situation that AntiSniffer detects.
As others have said, a switch can make sniffing more difficult. Not impossible, just more difficult. Remember that no computer can be 100% secure, unless of course it finds itself in the middle of a nuclear explosion.
This
No... (Score:1)
Re:"The Big Hit" (Score:1)
like in "the Big Hit" (Score:1)
unless he has a trace-buster-buster-buster that is
Re:Sniff of old news (Score:1)
that's my contribution.
anti sniffer (Score:1)
just my worthless opinion.
Can't always cut the Tx (Score:1)
The Tx can be cut on AUI lines since it is not the same line as the keep alive, but on RJ45 Tx and keep alive are the same line so if you cut Tx, the device on the other end will stop sending you data.
Another method that would work better (which was also on Bugtraq) was to sniff on one nic that had an unreachable address (eg 0.0.0.0) and have another nic in the sniffer machine to connect remotely with that has a valid IP. This hack practically requires a rewrite of the tcp driver tho so it would really one be feasable on an Open Source OS.
Promiscuous mode in 98/NT? (Score:1)
Impossible product. (Score:1)
Of course if the sniffer was running as a process on an NT or Windows 95 machine, then it is possible that sniffed packets get passed up to the protocol stack, but I have not been daft enough to run such a sniffer.
Looks like another means of making money out of ignorance.
Re:Impossible product. (Score:1)
It would also work on a token-ring network, but in this case there would be some MAC frames put on the ring.
I will pay £1000 to anyone who could detect that such a LANWatch PC was scanning an Ethernet network.
Re:Network General, anyone? (Score:1)
In other words, Anti-Sniff cannot detect a sniffer box unless it's running the less-popular Windows version of Sniffer.
At my last job at Adaptec we made the NIC cards used by Sniffer and my former boss worked in the Sniffer group at Data General. As a network developer I use a Sniffer all the time.
Sniffer is a trademark of Data General.
Re:Network General, anyone? (Score:1)
As of a year ago about 90% of the Sniffer sales included the special NIC card since that version came with the DOS version in addition to the Windows version. The Windows version is just too limited and not as easy to use.
Bullshit! (Score:2)
All this will protect you against is sniffers being run by legitimate machines. It won't protect you against a rogue machine.
-russ
Yea (Score:1)
Re:This is news? (Score:1)
Not easily (Score:2)
The l0pht anti-sniff program just does a couple of well known tricks to detect the response time of a normal machine hacked to be in promiscuous mode. A router could be used to do the same thing, just a bit more crudely, with less reliability (antisniff is pretty unreliable, I've been testing with it)
Your router admin sounds like a know-it-all with no real knowledge. Ask for details, and if you get anything solid then email me. I'm always looking for new tricks
the AC
Re:There is alreadi an anti-antisniffer sniffer (Score:1)
This always seems to be the conventional knee-
jerk reaction to sniffer protection. Obviously,
it is impossible to detect with software the
presence of a "hardware" sniffer. People who
insist on pointing this out repeatedly miss the
point: the overwhelming vast majority of malicious
sniffers are software, installed on general-
purpose computers.
A general technique to detect such sniffers would
have a dramatic beneficial effect.
Re:So what (Score:1)
More wrong-headed "conventional wisdom". The two
flaws in the logic that "switches solve sniffing":
A.) switches aren't designed for security (even
the ones with "security features"), and B.) there
are things you can do at the network layer that
affect the way the link layer works.
There are switches that will revert into an
"insecure" forwarding mode when room for
forwarding tables runs out (if you think about
this, you'll realize that there's basically no
way any switch can prevent this attack, other
than detecting it and locking down the offending
port). There are switches that can be "fooled"
by seeing a frame with an Ethernet address it
believes to be on a different port (forwarding
table updates happen instantaneously). There
are tens of other little problems like this that
can be exploited.
More importantly, there are games you can play
with IP that completely subvert switches; you can
race ARP, for instance, and transparently forward
captures packets. You can play games with dynamic
routing. Look at the recent L0pht advisory on
Router Discovery.
For something to be useful as a security device,
it needs to provide some degree of assurance that
it is doing what you expect it to be doing.
Switches, as "anti-sniffing" devices, fail this
test --- there is no way for you to know, outside
of expensive testing, not only of the switch but
of your entire LAN environment, whether or not
they are really providing any protection.
Re:So what (Score:1)
solution to most security problems. When the
entire Internet speaks IPsec, you will have
a valid point. Until then, LAN snooping is a
problem that is important to address.
Even when IPsec is deployed widely, the only
reasons sniffing will cease to be such an issue
is that so few people will be doing it anymore.
Right now, sniffer detection is a valuable means
of detecting _intrusions_, and after-the-fact
intrusion detection is obviously valuable when
you can't assure attack detection.
Re:tracing sniffers with corrupt ARP entries (Score:1)
This only works against a small number of broken
stacks. When we (Secure Networks, Inc) discovered
this technique several years ago, it only worked
reliably against Linux and SunOS (Ivan Arce, the
guy who came up with this idea, could tell you
better). Since then, operating systems have gotten
better about back-checking Ethernet addresses in
their drivers.
If you look at the AntiSniff material, this is one
of the checks they perform, and its limitations
are well-documented.
Re:Bullshit! (Score:1)
system and has "legitimate" network connectivity,
the presence of a promiscuous-mode sniffer on the
box will be detectable (not necessarilly by
AntiSniff --- I'm not very familiar with how
effective their implementation is) with latency
analysis.
Re:Impossible product. (Score:1)
act of measuring network traffic on a general-
purpose platform produces changes in that
platform. These changes are detectable.
Promiscuous mode sniffing alters the way the
Ethernet drivers work, it changes the performance
characteristics of the whole network system, and
it causes the platform to react to events it
wouldn't normally react to.
Common sense tells us that unless there's no
way to talk to the sniffing machine and thus no
way to take measurements, running a naieve (read,
not sniffer-sniffer-protected) sniffer is going
to change SOMETHING on the box we can detect.
Re:Someone in here smell horse manure? (Score:1)
A.) The "company" you're talking about never
published any research. They might as well have
never done it.
B.) Your idea of how the L0pht tool works has
very little to do with what the tool actually
does. The technique your "company" uses (which
is well-known, though undocumented) is not the
only (or even the most powerful) check done by
the L0pht tool.
C.) Physical sniffers are not the threat that
this tool purports to defend against, nor are
they a threat for the vast majority of networks
(in which physical access to the network is not
an issue).
L0pht, Credibility (Score:1)
at the L0pht are among the more respected in the
whole security industry (speaking as one who spent
a great deal of time in that industry). They're
responsible for a good deal of pioneering work,
and they have a reputation for doing things right.
Which is what I believe they are doing here, by
thoroughly documenting the way their tool works
and what its limitations are. We can study their
tool and determine through peer-review how
effective it is. And, if we wanted to, we could
use their research to build our own tools.
Which is only fair, because they are also using
publically available research to build their
tool.
Someone in here smell horse manure? (Score:1)
despite the fact that I had a discussion with
a guy 3 years ago whose company was doing
_exactly_ this same thing.
The theory is that if a machine is in promiscuous
mode, certain IP communications are not responded to. (Sending an ICMP error to the machine and seeing if you get a reply is one such test.)
So if your protocol stacks still respond normally, these tests don't work.
The problem is that 1) after my conversation 3
years ago, I managed to modify a public domain IP implementation that would sniff and not interrupt normal processing of packets, and 2) even if intruders are nice enough to use garbage stack implementations that respond like this, what if they are running a machine you don't know is there, and no protocol stack? No way to query the machine, no way to know it is sniffing.
The point is that this company is grandstanding on a couple well-known behaviours of promiscuous machines. Don't believe them. They'll not improve your security.
This is news? (Score:1)
But, since you brought it up, I would think an organization like l0pht would have thought of a better name for their product. Hmm, let's see, a product that detects others who are promiscuous. How about Celibacy? Or Puritan? Guess they're going corporate, huh?
Other Ways to Detect Sniffers (Score:1)
He's a real jerk so he may just be embellishing the truth.
-matt
Re:Not easily (Score:1)
Your router admin sounds like a know-it-all with no real knowledge.
I agree. When i pressed him for more he copped out, mentioning security issues that prevented him from disclosing the info. I don't wanna do anything wrong. I just want to learn.
Re:like in "the Big Hit" (Score:1)
I love that movie.
Heart attack -> life buster
pacemaker -> life buster buster
microwave -> life buster buster
Re:like in "the Big Hit" (Score:1)
microwave -> life buster buster buster
weak. I'll stop now
So what (Score:2)
Encrypted mail and such
Not that I'm any sort of security expert, but this sounds kind of like the Radar Gun Detector argument - if you're afraid of being pulled over in the first place, you have to work to change the speed limit, not try to evade the Radar Guns.
I knew that... (Score:1)
I don't know why we even bother...someone will always find a loop hole...
Why is it that thier are never fixed before someone exploits it? You'd think that somewhere and sometime, one of the good guys would find the exploit first.
Ah well...
Re:So what (Score:2)
True, if you're in the same VLAN you would see all broadcast/multicast traffic (unless the switch was capable of IGMP then you wouldn't even get all the multicast traffic). But, my experience is that broadcast/multicast traffic is not too useful for snooping passwords and such (at least for TCP/IP/unix connections and that's all we care about, right?).
Switches definately do not "guarantee security" but your method for snooping will not work. Even if you were able to get control of the conversation steering or port mirroring (or whatever your particular vendor calls it) capabilities of your switch there would be problems. First, you would have to be plugged into the same switch as the device you wanted to sniff. Second, you would probably only get half of the "conversation." A little know fact is that most switches are setup for auto-negotiation to 100BT full duplex. Most switches are unable to buffer frames while port mirroring. So if the device you are sniffing happens to be in full duplex mode and is sending a frame at the same time the switch is sending a frame to it you would only get one of the frames copied to your mirror port.
Besides, auto-negotiation does not always work and when it doesn't the results are not too pleasant. It varies between combinations of various vendor's switches and various NIC cards. Some combinations work excellent, some are intermittent, and some fail all the time. The end result is that some network engineers choose to force speed and duplex in all cases just so that there is no possibility of problems.
"The Big Hit" (Score:1)
"I have a call tracer blocker tracker blocker....."
Re:I knew that... (Score:1)
Re:Network General, anyone? (Score:1)