Know Your Enemy: Honeynets in Universities

Know Your Enemy: Honeynets in Universities
Know Your Enemy: Honeynets in Universities
Know Your Enemy:
Honeynets in Universities
Deploying a Honeynet at an Academic Institution.
Honeynet Project
http://www.honeynet.org
Last Modified: 26 April, 2004
Honeynets have demonstrated their value as a research tool in the area of Information Assurance (IA).
Many researchers and organizations in the security community, both public and private, are currently
employing honeynets to continue to gather knowledge concerning the tactics, techniques and
procedures of the hacker community. Since the summer of 2002, Honeynet Alliance members at The
Georgia Institute of Technology (Georgia Tech), successfully deployed a honeynet on the internal
network to collect information on hackers and to help secure their campus enterprise network. The
purpose of this paper is to help academic organizations deploy honeynets in .edu environments by
sharing with you their experiences and lessons learned. We assume that you have already read and
are familiar with the concepts of a honeynet as discussed in the KYE: Honeynets paper.
The deployment of a honeynet on a large enterprise network such as that found on a major college or
university can offer numerous benefits to an institution. Based on our experience, we identified two
primary benefits. The first is the ability to use the data collected as a teaching and research tool for any
type of computer security related course or research that is being offered. Professors and students can
potentially use the honeynet as a testing ground for classes or research. In fact, one student recently
received his Ph.D based on our honeynet. The second, and based on our experience the more
significant benefit of a honeynet, is it can serve as a network security tool to dramatically increase the
overall security posture of that institution's network. For example, our honeynet identified over 165
compromised systems on the GA Tech networks, providing extensive information what was
compromised, how, and potentially by whom. Later on in the paper we cover in greater detail the value
our honeynet provided GA Tech and its faculty, staff, and students.
Getting That Bad Boy Approved
Lets say you are interested in the idea of deploying a honeynet on your internal, academic networks,
for either research or detection purposes. Where does one start? The first step you need to take is
getting approval. A common concern for academic honeynets is permission; how do you get institution
authorization to deploy this on internal networks? One thing we learned is it is necessary to receive
permission from several organizations before establishing a honeynet at a University. This usually
involves two things; demonstrating the value of honeynets and addressing issues concerning legality,
security and privacy. These areas must be addressed since you will not own the network in which you
will be using to establish your honeynet. You must coordinate with your network administrators and
your university administration to ensure that issues previously mentioned are addressed. You do not
want to set up a honeynet without your network administrators being aware of it.
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For value, we initially requested to set up our honeynet for research purposes. Honeynets provide
fertile ground for research topics including: databases, distributed agents, data analysis, agent
technology, network fundamentals and advanced topics. Additionally, honeynets provide a wealth of
data collections for research. However, the honeynet also quickly demonstrated its value in detection,
we soon realized its role as part of the university security infrastructure. The value of honeynets extend
beyond the research lab and into the system/security administrators toolkit. As detailed later in the
paper, the deployment of honeynets at Georgia Tech has significantly increased the cyber-security
posture of the university.
The second area to be addressed are the concerns of legality, security and privacy. These are all
potential topics for the network administrators and the university administration to use as justification
for denying the honeynet deployment and must be addressed up front. It will most likely be necessary
to receive permission from the Network Administrators of your campus network in order to establish a
honeynet at your institution. Some network administrators may be reluctant to do so fearing that a
honeynet will increase the chance of a system compromise occurring. We have found the opposite to
be true here at Georgia Tech. The honeynet can provide additional analysts to examine suspicious
traffic that is occurring within the campus network. If the principle of data control is followed, the danger
posed by a honeynet machine being utilized to compromise any other campus machines is greatly
mitigated. Frequent monitoring of the honeynet data and providing frequent reports of suspicious
incidents to the network administrators should put them at ease concerning the establishment of a
honeynet. In our case, a network administrator (Technical Project Director from the Network Security
Branch of the Georgia Tech Office of Information Technology (OIT)) actually took an active role in our
honeynet initiatives, co-authoring a recent paper titled, The use of a Honeynet to Detect Exploited
Systems across Large Enterprise Networks. This paper is a detailed discussion of the usefulness of
honeynets in networks that can be used to help convince your network administrators of the value of a
honeynet in helping to secure the campus network. The campus network administrators should provide
you with IP addresses located within the production campus network.
In addition to the technical security buy-in needed from the network staff, the university administration
will have to approve the deployment of honeynets. The administration will primarily be concerned with
issues of legality and privacy. The best practice is to obtain a policy letter that identifies the legal and
procedural guidelines on the use of honeynets. One of the most frequently asked legal question is
whether a honeynet violates the Wiretap act. This question has been answered by the the United
States Department of Justice recognizing that a honeynet can qualify under an Exception to Wiretap
Act, the Provider Exception (System Protection) clause. The second legal concern frequently raised is
the question of entrapment. Given that honeynets are deployed on networks and no advertisement
enticing people to scan and/or break into the honeynet, the case of entrapment has little merit. A final
administrative legal concern is the privacy of data on the network. Information such a credit card
numbers, user IDs/passwords, social security numbers, and a myriad of other data could easily be
captured by a honeynet. Proper handling of this data is very important.
Your network administrators will most likely be aware of issues concerning the monitoring of traffic on
the campus network as well as what steps can be legally taken to secure the campus network. If this is
not the case, you, or the network administrators, may need to approach your campus legal
department. The Georgia Tech campus legal department has decided the use of a honeynet on the
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Georgia Tech campus networks provides the university with a legal method to unobtrusively observe
anomalous and misuse traffic directed on the campus network. The Georgia Tech Office of Information
Technology (OIT) has cleared the establishment of the Georgia Tech Honeynet with the Georgia Tech
Legal Department. OIT authorized us to establish and monitor a honeynet on the Georgia Tech
campus network in order to assist in protecting this network. These are the guidelines used at Georgia
Tech, and may need to be modified to meet the specific concerns of both the network and the
university administrators.
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The Georgia Tech Honeynet is located within the production address space of the Georgia
Tech Campus Network.
The Georgia Tech Honeynet uses computer operating systems that are representative of
computers found on the Georgia Tech network.
No IRC traffic is collected from our honeynet. If an IRC server is established on our honeynet
that machine is immediately taken off line. This is to stay in compliance with the US Wiretap Act
since a client utilizing that IRC may be unaware that the channel is on a compromised machine.
A user such as this may have an expectation of privacy. We decided that it is best not to take
the chance of violating the US Wiretap Act. Other nations will most likely have similar statutes
concerning means that can be utilized to secure networks.
Technology We Used
Once you get approval to deploy a honeynet, the next step is to decide what type you want to deploy.
There are currently two types of honeynets that can be employed on a network. These are GEN I, or
first generation, and GEN II, or second generation. The type of honeynet depends on many factors
including availability of resources, types of hackers and attacks that you are trying to detect, and
overall experience with the honeynet methodology.
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GEN I Honeynets - a simpler methodology to employ. This is the technology we choose to
initially deploy when we first set up our honeynet. Its simplicity allowed us to learn how to run
our honeynet. Although this is a simpler version of the honeynet, it still offers the opportunity to
learn a lot about the basics concerning honeynets.
GEN II Honeynets - a more sophisticated version of the honeynet. This is the current
configuration of the Georgia Tech Honeynet after learning the basics by utilizing a GEN I
technology. A Honeywall CDROM will soon be available that greatly simplifies the deployment
of a GEN II honeynet. For additional information on honeynet technologies, refer to KYE:
Honeynets.
We had chosen to initially deploy a GEN I Honeynet on our enterprise network. Our initial objective
was to detect machines within our enterprise network that had been compromised by automated script
type attacks in addition to collecting rootkit research. We also wanted to start simple. As we became
more comfortable with our data analysis methods we then employed a GEN II Honeynet in our
research efforts. Regardless of which type of honeynet you deploy, you will need resources
(computers, switches, hubs, etc). Fortunately, we found honeynets to be pretty cheap hardware wise.
The only people using your honeynet are attackers, so you don't need high performance systems. We
used surplus machines and available research lab space here at Georgia Tech to deploy our
honeynet. Surplus machines should be available at most academic institutions. Addition tools might
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include a KVM type switch box to provide the ability to connect the honeynet machines to a single
monitor and keyboard. If possible, the honeynet machines should be configured with removable hard
drives to allow for compromised systems to be analyzed off-line. Given the high probability of available
existing resources, you should not have to spend a lot of money for hardware to set up a honeynet.
Time, on the other hand, can become a high demand resource concerning the honeynet (hint, grad
students are cheap). We used surplus available resources here at Georgia Tech (to include student
time, which is free). Were we to purchase the current configuration we estimate it would cost:
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8 port KVM switch OSU21032 $355.00
Dell Dimension 2400 Computer x 8 @$675.00 $5400.00
Data Castle BT-27 removable drives 2 per computer @ $20.00 $160.00
Computer Rack $1058.00
Total $6973.00
Our honeynet, in its current configuration, could be set up for less than $7000. All computer resources,
to include a KVM switch box, surplus computers, and removable drives with a disk duplicator were also
available. It did not cost anything, besides time, to establish and maintain our honeynet. If you had to
buy the hardware we used, we estimate the cost to be $7000.00. You may find similar circumstances
at your university.
Maintaining and Monitoring our Honeynet
While honeynets may be relatively simple and cheap to deploy, they can be a time intensive endeavor
to maintain. Here at Georgia Tech we spend on average one hour per day to analyze traffic that was
collected from the previous day. Keep in mind, the advantage with a honeynet is that you are not
analyzing the data to determine what is hostile traffic and what is benign. Instead, with honeynets you
operate under the assumption that all data it collects is bad, the reason you are analyzing it is to derive
value from it. This makes honeynets a very effective tool for learning what unauthorized activity is
happening on your network. When we initially established the honeynet, we used a session of snort
running with the default rule set employed and then correlated these alerts against the tcpdump data
via ethereal in order to learn what to focus on in ethereal. When we began to get more comfortable
with snort we began to write our own snort rules to alert on specific suspicious traffic that we were
observing on our campus network. Later on, using the tcpdump data we were able to go directly to
ethereal and write our own filters to look for specific data. The capability to automate this analysis
process does not exist; however, someone will have to do the manual analysis to determine what to
automate on.
When a compromise occurs we expect to spend up to forty hours of analysis for each hour of attack
traffic that has been collected from the honeynet. This process can be very time consuming but very
rewarding. We now split this analysis up here at Georgia Tech and everyone who is involved in the
investigation contributes to the compromise report. A report is produced for every compromise that
occurs on the honeynet. Any suspicious behavior from campus machines directed to the honeynet is
also reported. These reports are sent to OIT personnel, professors, individual network administrators,
and other parties of interest here at Georgia Tech.
Our Honeynet Proves its Worth
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The Georgia Tech campus is typical of many university environments, we face many of the same
challenges and problems. We are very large environment required to give open access to many of our
resources, making it extremely difficult to secure. Some statistics of Georgia Tech.
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15000 Students, 5000 Staff, 69 Departments
Mix of many different computers and operating systems
Not uncommon to have systems that can boot up in four different operating systems
30000-35000 networked computers on campus
Academic, administrative, resident (REZNET), and research networks
Like many academic institution, we also find ourselves a large target, for several reasons.
1. High bandwidth capability to/from Internet (600Mbps/4 Terabytes per day here at Georgia Tech)
2. Lots of student machines with large storage capability
3. Can hide in "Academic Freedom" traffic. The concept of academic freedom concerning network
traffic is that since Georgia Tech is a research institution, network traffic should not be restricted
so that on-going research efforts are not interrupted. Because of the requirement for academic
freedom, Georgia Tech chooses not to implement a firewall between the campus network and
the Internet. Individual enclaves within the Georgia Tech network do utilize firewalls. An IDS is
also run at the campus gateway with Out of band monitoring and follow-on investigation. These
network characteristics make Georgia Tech well suited as a network to employ a honeynet as
an additional IDS tool. Other academic institutions may have similar characteristics and benefit
from the employment of a honeynet.
The original purpose, and one of the benefits of our honeynet, is research. The honeynet network is
used by students conducting research in the areas of operating system and network security here at
Georgia Tech. The honeynet has assisted in research efforts to include devising a new methodology
for characterizing rootkits to aid in their subsequent detection as part of Ph.D. research. Other Ph.D.
students are looking to incorporate analysis of the two years of honeynet data that we have collected
here into their Ph.D. research efforts. One research effort produced a detailed analysis of new and
existing rootkits collected from the honeynet and examination of inadequacies in the existing state of
the art rootkit detection methodologies. We have produced one paper concerning the analysis of a
previously unseen rootkit that was collected from the honeynet. We were able to characterize this
rootkit and produce signatures in order to detect subsequent incidents. We have also provided
suggestions to authors of GPL tools for rootkit detection in order address shortcomings and improve
their tools. There is a current on-going research effort incorporating the honeynet with a Darknet (a
research effort to track traffic to unused IP addresses) in order to establish a linkage between these
two types of IDS tools. As previously mentioned, the use of a honeynet allows for operating systems of
interest to be deployed in order to collect any attack traffic for subsequent analysis. The honeynet has
provided for multiple research papers to be written here at Georgia Tech as well serving as a platform
for on-going computer and network security research.
We have also found the honeynet to be an outstanding teaching tool - working with the honeynet
provides hands-on experience to students who monitor the honeynet as part of an independent study
program. This hands-on work provides a number of opportunities for these students. Studying the
attacks and the root-kits allows these students to produce documentation and notes on how and when
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the attacks occurred as well as analysis of the root-kits: how to remove them, how they work, and how
they could be improved. As a member of the Honeynet Alliance, Georgia Tech is expected to send a
report each quarter to the Alliance detailing what we have seen on our Net. The students who monitor
the honeynet as part of their independent study are expected to produce this report as well as a report
of any compromise that occurred during this time period. Honeynet data is also used in network
security classes in order to teach students how to use tools such as ethereal and tcpdump in order to
analyze attack traffic. Presentations on the honeynet are also given to classes and other group s of
interest. During the 2003 'Capture the Flag' network security exercise hosted by the University of
California Santa Barbara (UCSB) technology from the GEN II Honeynet was employed. A session of
Snort-Inline was run in order to analyze attack traffic. One Georgia Tech team placed third in the
exercise after two UCSB teams.
What surprised us was the tremendous value of a honeynet for detection. Our honeynet helped to
accurately detect over 165 compromised systems on our internal network. As our honeynet had very
few false positives, it was in many ways easier to use, and more effective, then traditional detection
technologies. Its greatest detection benefit was the ability to give detailed information, we were able to
collect all data concerning these actual compromises to include passwords, remote IP addresses, and
the methods of compromises used by the hackers. Very early on in its deployment our honeynet
enabled us to identify an internal Georgia Tech system that had its passwords compromised by a
hacker. This system was then used by the attacker to connect to other internal systems, including our
honeynet. Our honeynet quickly identified this attacker and the tools and tactics he was using to
infiltrate systems. The attacker set up a back door port on the honeynet in order to connect at a later
time. We knew that this system had been compromised but keep it up and running in order to track the
hacker's behavior. Several days after this system was compromised the hacker connected to the back
door port established on this computer using another computer from within the Georgia Tech
Enterprise Network. We immediately notified the Georgia tech Office of Information Technology (OIT)
personnel of this other potential compromised computer on campus. The OIT personnel took this
computer off-line for analysis. Upon conducting analysis the OIT personnel could not find any
indication that this other machine had been compromised. We learned this machine was not
compromised by an exploit; instead it appeared the password to the system had been compromised.
OIT personnel speculated that the hacker used some method to get the password of this machine. The
hacker could have used a brute force technique to guess this password. He could have harvested this
password from a dummy web site set up to harvest usernames and passwords from unwitting users
(social engineering). The OIT personnel instructed the user to change his password by selecting a
password that was more secure and to not use this password when establishing accounts at other web
sites. The Georgia Tech OIT personnel have stated that it would have been very difficult for them to
detect that this system had been compromised using the existing security measures that they have
available. Our GEN I Honeynet allowed us to detect a system that most likely had been compromised
by a hacker with some skill. At this point the Georgia Tech OIT personnel became supporters of the
honeynet after having seen its worth in detecting compromised systems on campus. Since its
establishment in the summer of 2002 the honeynet has detected over 165 compromised machines on
campus.
Lessons Learned
Out of all of this were a variety of lessons learned things to do and NOT to do. Hopefully this short list
can help you avoid some common mistakes.
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1. Start Small - If you are going to install a honeynet within your enterprise, start small. Begin
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initially with two machines (in order to detect sweep scans of your honeynet) with operating
systems that you are familiar with installed behind the reverse firewall. This will allow you to
begin to understand how to analyze the data that you will receive on the honeynet. You will also
be able to fine tune your configuration. The more machines that you have, the more data you
will most likely receive going to and from the honeynet.
Maintain good relations with your enterprise administrators. THIS IS CRITICAL! Inform your
network administrators of the types of exploits that you are seeing. In some cases, they will
already be aware of these exploits, but in other cases, you will have been the first person to
notice them. The enterprise administrators should benefit from your efforts since they most
likely provided you with the range of IP addresses that you are using for the honeynet.
Focus on attacks and exploits originating from within your enterprise network. Theses are the
attacks that can do the most damage to your enterprise. Inform your enterprise administrators
immediately of these types of attacks since they indicate machines that have already been
compromised within the enterprise.
Don't publish the IP address range of the honeynet. There is no need to do this. Hackers and
worms are constantly scanning across the Internet for machines to exploit. You honeynet will be
found and attacked.
Don't underestimate the amount of time required to analyze the data collected from the
honeynet. This data must be analyzed every day. You will be collecting lots of information and it
must be analyzed to provide any benefit. Most attacks take seconds to compromise and take
over a vulnerable system. It can take weeks to analyze and document such an attack. Once
again, we think its well worth the effort.
Powerful machines are not necessary to establish the honeynet. The Georgia Tech Honeynet
did not use state of the art machines and it functioned as intended. Everything we needed to
establish our honeynet was already available on campus.
Conclusion
Honeynets can be a very powerful tool when deployed in an academic environment. Not only can it be
used for securing your production environment by acting as a reliable and in-depth detection solution,
but can also be used for a variety of extensive research projects. GA Tech has had great success
applying honeynets to both areas.
The Honeynet Project
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