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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Dynamically Correlating Network Terrain to Organizational Missions</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>A. E. Schulz</string-name>
          <email>alexia.schulz@ll.mit.edu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>B. David O'Gwynn</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>y J. Kepner</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>P. C. Trepagnier</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>MIT Lincoln Laboratory</institution>
          ,
          <addr-line>244 Wood St., Lexington, MA 02420</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>A precondition for assessing mission resilience in a cyber context is identifying which cyber assets support the mission. However, determining the asset dependencies of a mission is typically a manual process that is time consuming, labor intensive and error-prone. Automating the process of mapping between network assets and organizational missions is highly desirable but technically challenging because it is difficult to find an appropriate proxy within available cyber data for an asset's mission utilization. In this paper we discuss strategies to automate the processes of both breaking an organization into its constituent mission areas, and mapping those mission areas onto network assets, using a data-driven approach. We have implemented these strategies to mine network data at MIT Lincoln Laboratory, and provide examples. We also discuss examples of how such mission mapping tools can help an analyst to identify patterns and develop contextual insight that would otherwise have been obscure.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1 INTRODUCTION</title>
      <p>Situational awareness of cyber assets, as well as their function in
supporting the organizational missions, is crucial to mission
assurance, both for prioritizing cyber key terrain (KT-C) to defend
and for understanding the attack surface presented to an adversary.
Equally critical is understanding an organization’s sources of data,
and how those data sources are utilized in support of the mission.
The resources for defense of cyber assets are always limited. An
organization can only allocate those resources effectively if they
are aware of their cyber assets, and how those assets support the
organization’s goals.</p>
      <p>
        Thus, mapping cyber assets onto organizational missions is
critical for situational awareness, risk assessment and resource
allocation. Many researchers, both in the military and in industry,
have been developing manual processes to meet this critical need
[
        <xref ref-type="bibr" rid="ref13 ref14 ref2 ref3 ref4 ref5 ref7">2, 3, 4, 5, 7, 13, 14</xref>
        ]. Manually produced maps are better than
nothing, but they have severe disadvantages. They only consist of
a single snapshot in time, and do not dynamically evolve as
cyber assets are reshuffled within an organization. Also, they do not
scale. As cyber assets become more multi-purposed and mobile, the
timescale for reshuffling critical infrastructure will likely become
so short that a manually assembled map may become obsolete even
before it has been completed. Automating the process of mapping
between network assets and organizational missions is highly
desirable, but technically challenging because it is difficult to find an
appropriate proxy for asset importance within available cyber data.
However, although full automation may not be possible, most
organizations have access to data sources that can be used to partially
automate the mission mapping process, providing a starting point
which can be manually refined.
      </p>
      <p>Identification of appropriate live data sources that act as a proxy
for organizational missions is an open research question. In this
work we focus on the use of financial data to serve as a proxy for
mission. Section x2 discusses our basic methodology. In section
x2.1, we outline the technology goals for a suite of mission mapping
tools developed at MIT Lincoln Laboratory. For brevity, we will
refer collectively to this suite of utilities as PCAMM, or Person
Centric Automated Mission Mapping. In section x2.2 we discuss
one possible implementation. In section x2.3 we outline some of
the applications of PCAMM, with some examples drawn from data
at MIT Lincoln Laboratory. In section x3 we draw conclusions,
discuss the drawbacks and limitations of this approach, and outline
open research questions for the future.
2</p>
    </sec>
    <sec id="sec-2">
      <title>METHODOLOGY</title>
      <p>The key challenge in this work is to develop mapping technology
that is automated and data driven. There are three principal insights
that guide our basic approach. The first and most fundamental is
that the link between network assets and organizational missions is
the workforce: people are required to carry out tasks and
accomplish goals, and people are also the users of an organization’s
network. If the people can be mapped to the organizational missions,
we can pivot through them to the network assets that they use in
executing their tasks.</p>
      <p>The second insight is that finance data provides a mechanism
to find out what the people in an organization are doing without
manually interviewing them. All government and business entities
have a charging structure. The money they spend is subdivided
according to what the money is for i.e. the missions and programs.
The money is also distributed to people who work on those missions
and programs. Therefore the finance data provides a link between
the people and the missions.</p>
      <p>The third insight is that different questions will require the
mission map to be enriched with different data sources. The finance
data providing the link between people and missions is not “big”
in the sense of big-data. These can exist entirely in memory, even
for a very large organization. However, enriching the mission map
with all the network log data at once cannot be approached with the
fast in-memory hash-map technique used for the unenriched
mission map. Since we need a forensic tool that is lightweight and
fast, we engineer a way to leverage the big-data assets and pivot on
the fly to whichever network data sources help answer the specific
question.
2.1</p>
    </sec>
    <sec id="sec-3">
      <title>Technology Goals</title>
      <p>The development of our suite of mission mapping tools, which we
call PCAMM, is guided by a number of overarching technology
goals. The intent is to map network and cyber infrastructure to
organizational missions. The tools should provide a method to
identify mission critical assets: key users and accounts, as well as key
infrastructure. They should provide insight on the mission impact
of compromised accounts, compromised or unavailable machines,
and both the network and organizational role of Information
Technology (IT) systems of interest.</p>
      <p>
        Although the PCAMM software is not limited to visualization of
the data, it is designed to conform to Ben Schneiderman’s mantra
[
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. It should provide overview data and big-picture mission
context; it should provide search and filter capability; and it should
provide details on demand, allowing the user to specify new layers
of enrichment on the fly. The mission mapping tools are designed to
allow real-time mission-driven sense-making and forensic capacity.
      </p>
      <p>Distribution A. Approved for public release: distribution unlimited
Finally, PCAMM should be as automated as possible. The goal
is to use data to identify key network infrastructure, so that the tools
can provide real-time context that doesn’t get stale as a network
evolves.</p>
    </sec>
    <sec id="sec-4">
      <title>2.2 Implementation</title>
      <p>2.2.1</p>
      <sec id="sec-4-1">
        <title>Prototype</title>
        <p>
          We have built a prototype implementation of the automated
mission mapping tool. We emphasize that this is just one possible
implementation; if an organization has the requisite data available in
their environment, these ideas could be executed in any of a
number of ways. Our implementation consists of three distinct pieces:
a data layer consisting of an Accumulo database; a knowledge
engineering layer consisting of a domain specific language (DSL),
implemented in Python, used to interface with the database, and
a mission mapping interface, written in Python, that leverages the
DSL to build the mission map and enrich as needed. We focus on
the third layer in this work, but again wish to emphasize that the
Python-based approach utilized in our proof-of-concept
implementation was chosen tactically for speed of development, as it
interfaced easily with LRNOC’s existing LLCySA platform [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ]. Many
other frameworks (e.g. the ELK stack or a SQL database) are also
possible.
        </p>
        <p>The primary class in the mission map utility is a person. A
person has unique attributes, such as a user id, an email handle or a
network account name. A person also has attributes that are shared
with other people, such as a research group or a job title. Some of
the attributes are one-to-one, such as person’s first name. Others
are one-to-many, such as the programs a person works on. In this
latter case, the value stored in the attribute is a list. These person
objects are combined to form another type of class: a person-list.
The person-list is fundamentally a hash-table which is keyed on one
the the unique attributes of the people in the organization, such as
a badge id number. Most of the operations carried out by PCAMM
are actuated by manipulating person-list objects. The key feature
of the person-list class is the enrich method, which takes any
dictionary of data keyed on people and uses it to add attributes to the
people in the map.</p>
        <p>As with any data store, one critical tool built into PCAMM is the
slicing tool. The slice feature allows the user to filter the mission
map on any attribute of a person, and return a slice whose members
either all have, or don’t have, that attribute. It is useful to break the
mission map of an organization into sub-maps (slices), each
mapping out some subset of whole enterprise. The sub-maps can be
unique, or they can be overlapping. Making a slice for every
possible value of an attribute is a process that we call organizational
breakdown. A breakdown is stored as a dictionary structure where
the keys are the Nval possible values the attribute can take, and the
value is a sub-map: i.e. the corresponding person-list. The
breakdown computation is an embarrassingly parallel process, and the
computation time scales approximately as
tbreakdown</p>
        <p>O(tsg Nval=Nproc)
(1)
where Nproc is the number of processors the user has available,
and tsg is the computation time to generate one slice, which scales
approximately as the number of people Np populating the map:
tsg O(Np).
2.2.2</p>
      </sec>
      <sec id="sec-4-2">
        <title>Data sources</title>
        <p>
          The mission map is populated with data from the organization. The
data sources are divided into two categories, organizational data
sources and network data sources. The organizational data sources
are used to build the un-enriched mission map, which we describe
shortly. The network data sources are used to enrich the mission
map, at the operator’s discretion, with log data that is typically
available in a Network Operations Center (NOC). We emphasize,
however, that any data associated with people can be used to enrich
the map. The data used in the prototype implementation PCAMM
is data assembled from the MIT Lincoln Laboratory network, which
is stored and accessed in the Lincoln Research Network Operations
Center (LRNOC) [
          <xref ref-type="bibr" rid="ref6 ref9">6, 9</xref>
          ]. The data is accessed via the Lincoln
Laboratory Cyber Situational Awareness (LLCySA) platform [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ].
        </p>
        <p>One of the organizational data sources is phone book or
directory data; usually Lightweight Directory Access Protocol (LDAP)
data in LDIF format (LDAP Data Interchange Format), though the
directory data could be in any format. The directory data typically
provides names, identification numbers, usernames, email handles,
phone numbers, office locations, job titles, as well as information
from the organizational chart such as the divisions and groups for
the people in an organization. The directory data is used to create
a person-list that will form the backbone of the un-enriched
mission map. We have enhanced the map by binning the job titles into
broader roles within an organization. For Lincoln Laboratory, the
roles we use are research, technical support, administrative support,
leadership, information technology, security and students. This
assignment of titles to role categories is one example of a manual
processes that fits into the mapping framework. For our work, we
have also used data from Human Resources to enrich the map with
university degrees, as a proxy for subject-matter expertise.
(However, in military contexts much more precise occupational specialty
data are available.)</p>
        <p>To create the un-enriched mission map, the directory data
backbone is fleshed out with organizational financial data. There are two
main inputs that are required for this approach. The first is the
labor charging structure in the organization; for each person there is
a record of which programs were charged in each month, as well as
the fraction of time that was charged to the program. The second is
finance data on the mission allocation of money used to fund each
program, that is, which mission area is supported by each program.
Although it is possible that this mapping may need to be manually
assembled, it is common practice in most business offices to
maintain such a list and often the data already exists, as it did in the case
of Lincoln Laboratory. Once these data sources are incorporated
into the map, each person will have a list of programs they
contribute to, and a list of mission areas (and potentially submissions)
that they support. This is the un-enriched mission map.</p>
        <p>
          The mission mapping tool functions by taking this base-level
mission map and enriching it in an ad-hoc fashion with network
security data that is housed in some underlying database. In our
case we have used the Lincoln Laboratory LLCySA platform [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ],
but as previously mentioned any queriable database structure is an
option. There are several network data sources that we have
incorporated into PCAMM. One of the most important are the
authentication logs. These provide a mapping between users and machines
that they utilize, either by directly logging on with a username and
password, or authenticating with kerberos credentials. Another
important source is the property tracking data, which help us to map
between users and the machines they own. We have also
incorporated Nessus [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ] vulnerability reports, which tell us which network
assets are potentially targets. Mail exchange metadata can reveal
more informal communities within the organization. Other
possible data sources include web proxy logs, VPN logs, IDS alerts and
host-based security system data such as logs from McAffee [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ]. For
any of these network indicators, we can pivot through the people
associated with the machines of interest to the missions and programs
that are potentially affected.
2.3
2.3.1
        </p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Use cases</title>
      <sec id="sec-5-1">
        <title>Overview Utilities</title>
        <p>There are a number of utilities modeled on database queries that
build on the mission map infrastructure to provide added
functionality to PCAMM. One such utility is the getall(attribute) method.
This method aggregates all values of a particular person-attribute
for people in the map, and returns a list of these values. For
example, an analyst could create a sub-map whose members were
owners of vulnerable machines identified in a Nessus scan. The
getall(emails) method could be used to retrieve a list of the owners’
email handles, quickly generating a distribution list to whom patch
information should be sent.</p>
        <p>A related utility is the gethist(attribute) method. This method
returns a dictionary: the keys are each possible value of an attribute
and the values are the number of people who possess that value of
the attribute. Calling gethist(missions) will enumerate how many
people in an organization work on each mission area. Calling
gethist(loginfails) on each sub-map in a mission breakdown can
indicate whether any particular mission area is the target of a password
spraying attack. For convenience the the plothist(attribute) method
displays a plot of the histogram.</p>
        <p>The PCAMM software allows the user to quickly enrich
external data sources with programmatic or mission context. Figure 1
demonstrates this: the raw data are active directory log events of
failed login attempts at MIT Lincoln Laboratory between 24-27
Feb 2014, which have been enriched with mission context using
PCAMM. We only plot three of the mission areas in Figure 1. On
Feb 26th around noon, there was an event generating failed login
counts several orders of magnitude higher than the baseline. Figure
1 shows that these events potentially have more impact on one of
the mission areas than the others. This is only one example. Since
PCAMM allows an analyst to enrich any new data source with
mission context, any event data associated with hosts, ip addresses, or
people can be enriched with programmatic or mission context in
this way.</p>
        <p>The data in the mission map is inherently graph data, with nodes
and edges that connect the various attributes such as ip addresses,
missions and people. However graph representation of the data
often does not convey sufficient contextual information to be useful.
Our approach to this difficulty is to use a configurable treemap to
convey context in a flexible way. The breakdown method described
in section 2.2.1 can be applied recursively. The result is the creation
of a tree data structure that provides an overview of the components
that make up an organization. The tree([list of attributes]) method
provides a convenient way to explore the data to understand large
trends. An example, shown in Figure 2 with data from MIT Lincoln
Laboratory, might be to break down the organization by mission and
then by ip, to see which assets are most commonly utilized by each
mission area. It is particularly powerful that the user can specify
whatever branching order best answers the specific question.</p>
        <p>Figure 2 reveals that some assets are commonly used by
everyone in the Laboratory, whereas others are used only by specific
mission areas. The tree utility accepts a list of values to ignore, in case
the user would like to exclude the mail server or other common
assets. The method will build trees to arbitrary depth, which is
combined with a zoomable functionality in the visualization, that allows
the user to descend down to successive layers. Only two layers of
the tree are simultaneously visible in a given view. For example,
if we had built this tree with branding order [missions, ips,
nessusplugins], the nessus id numbers would be hidden in the top level
view. However the analyst can click in any of the mission areas.
The visualization would zoom in and show one ip per colored area,
with subdivisions depicting nessus plugin id.</p>
        <p>Mission  7  
Mission  6  
Mission  5  
Mission  4  </p>
        <p>Mission  3  
Mission  2  </p>
        <p>Mission  0  
Mission  1  </p>
        <p>Legend  
Removed    </p>
        <p>
          One of the goals of PCAMM is the discovery of relationships
between network entities, people, missions and programs. To this end
there are two useful utilities that quantify the extent to which
entities are ”connected,” the correlation method and the pattern method
(discussed in section 2.3.2). The correlation utility is best explained
in terms of a Venn diagram. If two populations overlap, one can
compute the conditional probability that a person in set A is also a
member of set B with Bayes’ theorem (e.g. [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]).
        </p>
        <p>P(BjA) =</p>
        <p>P(A \ B)</p>
        <p>P(A)
=</p>
        <p>No=NT
NA=NT
=</p>
        <p>No
NA
(2)
Here No is the number of people in the overlap region of the Venn
diagram, NT are all the people in the organization, and NA and NB
are the number of people in groups A and B, respectively. This
probability quantifies the correlation of the two properties represented
by A and B within the organization, and is equal to 1 if the two
properties correlate perfectly (i.e. complete overlap of the Venn
Diagram). The method correlate(attribute1,attribute2) will compute
the correlation of every value of one attribute with ever value of
another. Computing the autocorrelation will quantify the clustering
within an attribute, for example, correlating programs to programs
will quantify what fraction of personnel are shared between any two
programs.</p>
        <p>Because the correlate function is many-to-many, it
doesn’t lend itself well to visualization. Therefore, a
plotHost  IP  Address  Removed    </p>
        <p>Homeland  Protec.on  
Spear-­‐phish  targets  
corr(attibute1,value,attribute2) method will display the correlation
of one specific value of attribute A with all possible values of
attribute B. Figure 3 shows data collected in a 24 hour period on
Apr 29th 2014. The plot shows the probability that a user of the
host at the obscured ip address works on a given program along the
x axis. The data depicted are real, but the ip and program numbers
have been obfuscated for MIT Lincoln Laboratory operational
security. This type of analysis could be useful in quantifying which
programs are potentially at risk, in the event the host at this ip
address were compromised.
2.3.2</p>
      </sec>
      <sec id="sec-5-2">
        <title>Pattern Utilities</title>
        <p>A critical part of situational awareness is the ability to recognize
and match patterns in the data. For example, if network assets are
found to be compromised, it is reasonable to inquire whether a
particular individual is associated with them. It is also useful to know
whether these assets work in concert to support some programmatic
or mission function. Such patterns may help an analyst to decipher
the root cause of the infection, and whether there is a particular
target of the compromise within the organization. Pattern matching is
critical for searching out other individuals who may be affected, or
identifying other network assets potentially at risk.</p>
        <p>The cartoon in Figure 4 illustrates this idea. Suppose malware is
detected on the laptops of persons A, B and C. The pattern method
can help identify what these people have in common. In this
example, they all support the Homeland Protection mission area, they
all charge to a particular program, and they have all been targets in
a recently identified spear-phishing campaign. Discovering this
information is useful for potentially tracing the source of the infection
to a phishing attack, identifying which program and mission areas
are potentially impacted, and locating person D. This person has
many features in common with A, B and C; their assets may also
be infected, or person D may inadvertently have been the vector
propagating the infection.</p>
        <p>The pattern() method can be called on the mission map or any
sub-map. It systematically examines data with which the map has
been enriched. It returns a sorted list of tuples, containing the
attribute, the most common value found in the sub-map, and how
many people share that value. An example is shown in Table 1.
The pattern() method was used on a sub-map created for this
example, which corresponds to owners and users of assets at several ip
addresses at MIT Lincoln Laboratory. There are seven individuals
in the sub-map, and these results show that collectively they work
D</p>
        <p>C</p>
        <p>B</p>
        <p>A
on 22 programs in the Space Control mission area, many of which
are sponsored by Other DoD sponsors. Owners and users of these
machines happen all to be female members of the research staff. If
these machines constituted a list of compromised assets, this
pattern might help an analyst determine that the vector for the threat
was somehow connected to a professional association of technical
women. The analyst can use the map technology to explore this
hunch further. For example, she may be curious to see if these
women have recently attended some conference in common. She
could use the enrich() method to add travel data to this sub-map, and
potentially discover how many of these individuals had attended a
recent conference on women in STEM fields.</p>
        <p>The functional inverse operation of the pattern() method is the
pattern match() method. A user supplies a template with feature
values, and the map is scanned to return a sub-map whose members
match the template. An example template used identify person D
(as well as A, B and C) in Figure 4 might be (missions = Homeland
protection, programs = 10, speardates != None). Pattern matching
is accomplished by repeatedly applying the slicing algorithm. It
is an example of a utility that would be easier to optimize if the
mission map were implemented directly in a database, rather than
the in-memory prototype discussed in this work.
3</p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>DISCUSSION</title>
      <p>We present in this paper an important first step in dynamically
correlating cyber terrain to organizational missions. Such a mapping
is critical for enhanced network situational awareness, for
developing forensic insight, for assessing risk and optimally allocating
resources to defend mission-critical assets. Our approach of
incorporating finance data and identity stores with passive network
monitoring and log data demonstrates that an approximate map can
be built dynamically, providing insight that would not otherwise be
available. However, there are limitations to this approach. First, this
implementation uses authentication data as a proxy for asset
importance. While frequency of use is one important indicator, it will
overemphasize the importance of some assets, and will potentially
miss other critical assets such as servers and routing infrastructure,
whose use does not typically require authentication. One
important extension of this work that will greatly mitigate this inaccuracy
is the addition of logs from routers or switches, that lend insight
into internal connections between machines. With this new source
of information each person could be associated with a list of hosts
and/or ip addresses that they directly use, as well as a second layer
of hosts/ips observed to connect with the first layer in netflow data.
Not only will this provide more complete insight into the assets
used in a given mission area, it will also be critical for baselining
internal network connectivity, deviations from which can help
indicate potential insider threats or lateral movement.</p>
      <p>Another drawback of this approach is the heavy reliance on
finance data to identify the missions and programs. While this
mapping is likely to exist for most organizations and business entities,
it will be far more accurate in some cases than in others. Following
the money will always provide an approximate proxy for
organizational mission structure, but it would be best to combine this with
other indicators of a person’s role or work function. These indicia
will in many cases be directly available, but may be augmented by
e.g. semantic analysis of their documents or email.</p>
      <p>Another potential improvement to the implementation presented
here will be to add data dependencies of the various missions and
programs to the map. This will provide a secondary indication of
asset importance, particularly for database and server infrastructure.
It will also help interpret the risk associated with adverse events,
such as a discovery of data exfiltratration, to the missions and
programs. We reserve an analysis of mapping data dependencies for
future work.</p>
      <p>Despite these imperfections, the PCAMM implementation has
demonstrated that pivoting through employees to filter for attributes
of interest is a highly effective way to increase network situational
awareness and convey mission context. The PCAMM software
provides</p>
      <p>Overview
– Display histograms for a program, division or mission
– Create treemaps showing the distribution of subgroups
and sub-subgroups
– Compute statistics and distributions for aggregated
quantities
– Identify rare attribute values
– Filter on a particular feature to create a sub-map
– Correlate between any attribute and any other
– Identify individuals who meet some profile</p>
      <sec id="sec-6-1">
        <title>Zoom and Filter</title>
      </sec>
      <sec id="sec-6-2">
        <title>Pattern identification</title>
      </sec>
      <sec id="sec-6-3">
        <title>Details on Demand</title>
        <p>Mapping network assets onto organizational missions is vital for
identifying infrastructure and quantifying its mission impact,
identifying interdependency of mission components, identifying
patterns and finding other assets that meet a profile. Mapping informs
the optimization of resource allocation, helps to quantify risk, and
provides the basis for mission assurance. We have demonstrated
some initial capabilities toward the ultimate realization of
dynamically achieving these goals, and are searching for appropriate
usecases on which to test and calibrate the method.</p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>ACKNOWLEDGEMENTS</title>
      <p>The authors wish to thank the members of the LLCySA team for
their support of this work. They also acknowledge useful
conversations with Jeffrey Gottschalk, Bill Streilein, Bill Campbell and
James Riordan. This work is sponsored by the Assistant Secretary
of Defense for Research &amp; Engineering under Air Force Contract
#FA8721-05-C-0002. Opinions, interpretations, conclusions and
recommendations are those of the authors and are not necessarily
endorsed by the United States Government.
– Identify commonalities between persons (or machines)
of interest
– Identify others assets that fit the pattern
– Retrieve data for any person or group of interest</p>
    </sec>
  </body>
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