Page tree
Skip to end of metadata
Go to start of metadata

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 22 Next »

Table of contents

Introduction

The information technology evolution has changed the human life in all spheres, making information one of the most valuable resources. Same as other resources, information is valuable for its owner and can cause disputes and conflicts. That's why, the information security should be taken seriously into account. The information systems development and the large amounts of data accumulation require an integrated approach in ensuring the security of the technical systems.

This document describes the information security methods used in networks comprised of Infinet Wireless devices. Each wireless device family has its own capabilities of application security tools, so at the end of a document's section you will find links to the technical documentation of each described tool.

Terminology

  • Information - knowledge about the world and the processes in it, perceived by a person or a special device.
  • Information Security (IS) - the security of the information and of the infrastructure components against influences that may harm the subjects of information relations.
  • Technical company policy - a set of technical solutions necessary to be used by the company's technical systems. The technical policy includes requirements for installation, operation and configuration of the devices. It is necessary to carry out periodical updates of the document and check its proper implementation.
  • Threat - potential violation of the information security.
  • Attack - attempt to realize a threat. An attack can be either malicious or not.
  • Attacker - a person or group of people making an attack.
  • Echelon - a subject for attack prevention, implemented as a part of an information security policy.
  • Risk - the likelihood of a specific threat.
  • Responsibility area - a network segment which has a certain subject  responsible for its effective operation. A subject can be either a specific person or an organization.
  • Internal network segment - a network segment that is in the responsibility area of our organization.
  • External network segment - a network segment that is under the responsibility of a third-party organization or client. Since the external network segment is managed by a third-party organization, the crossing of the internal and the external network segments is a source of threats.

Information Characteristics

Information security measures should be applied in accordance with the company's IS policy. The IS policy should take into account the following information characteristics:

  • Accessibility - the ability to access information in an acceptable time.
  • Integrity - relevance and consistency of the information.
  • Confidentiality - the impossibility of obtaining unauthorized access to information.

An information security policy should include measures to ensure each of the basic information characteristics. If the described information characteristics aren't respected, it may lead to financial, reputation and other loses. Remember that the IS policy implementation is an endless process that requires periodic review of the measures and of their implementation.

The IS organization should be multilevel and not only realized with technical solutions. In addition to technical measures, legislative, administrative and procedural measures should be provided.

Scenarios for Infinet equipment 

The measures to ensure the IS are determined not only by the Infinet device family, but also by the scenario of their use (Figure 1a-d). Let's look at several scenarios in which wireless devices connect network segments belonging to different responsibility areas, each area being characterized by a certain set of threats:

  • joining of internal network segments;
  • connection of internal and external network segments;
  • internal network segments connected with the Internet.

The security measures should correspond to existing risks, the IS architecture should not be redundant. For example, filtering of external connections should be performed at the interface on border with a third-party telecom operator, not on all the intermediate nodes of the network.

The requirements for physical safety and security in the radio link are the same for all the scenarios below and are described in detail in the relevant sections. In order to configure the devices, let's specify the following general requirements for information security:

  • the management of the external devices should be limited by whitelists;
  • service network protocols should not leave the internal network segment;
  • at the border of responsibility areas, an internal segment should be protected from malicious traffic.

Joining of the internal network segments

The simplest scenario is joining two network segments located in the same responsibility zone (Figure 1a). The devices are used as a bridge using a simple connector in the LAN structure, therefore, the main information security tools are located at the boundaries of the left and right segments.

Figure 1a - Radio link joining two internal network segments

Connection of internal and external network segments

In the scenario of connecting two networks located in different responsibility areas, the information security measures are implemented on a radio device located at the border of the two segments. A special example of the external network segment is the client’s network, which is provided with a data transmission service. In such scenarios, both inbound and outbound traffic should be filtered.

Figure 1b - Radio link connecting internal and external network segments

Figure 1c - Radio link connecting internal and external network segments

Internal network segments connected with the Internet

The scenario where a wireless device is located at the border of the internal segment and the Internet is a special case of the previous scenario's external network. The difference is in a low security on the device from the side of the Internet connection, that causes a large number of risks.

Figure 1d - Radio link connecting internal network segments and the Internet

Information security measures in various scenarios

The IS realization is achieved by the implementation of the measures described in the sections and in the subsections of the IS:

IS sectionIS subsectionApplication
Physical securityAll

ALL SCENARIOS

Radio SecurityAll

ALL SCENARIOS




Device management

Authentication

ALL SCENARIOS

Access method

LAN - EXTERNAL LAN

LAN - WAN

Management interface

ALL SCENARIOS

Firewall

LAN - EXTERNAL LAN

LAN - WAN

Access recovery

ALL SCENARIOS


Data transmission

General recommendations

ALL SCENARIOS

Data transmission settings

ALL SCENARIOS

Network protocol settings

ALL SCENARIOS


Infrastructure

Monitoring

ALL SCENARIOS

History storage

ALL SCENARIOS

Technical Accounting

ALL SCENARIOS

Physical security

The physical layer is the foundation of information security, so the devices physical security has a priority over company technical policy. Physical security should be comprehensive and include several components:

  • site selection for equipment installation;
  • organization of auxiliary facility infrastructure;
  • equipment installation;
  • facility operation.

The communication node (including wireless devices) consists of three main elements (Figure 2):

  • High-rise part: the location of wireless devices, for example, the roof of a building, a mast, a telecommunication tower.
  • Cable route: cables connecting the high-rise part and the equipment located indoor.
  • Building: equipment located indoor and points of connection to the infrastructure. Infrastructure may include data channels, power, climate systems, etc. Equipment should be placed in a rack or telecommunication enclosure, which can be placed in a dedicated room or be combined with the high-rise part of the object.

Figure 2 - Communication node block diagram

Site selection for equipment installation

The site for the equipment placement must meet the requirements of the company technical policy and make possible the future communication node development. Following aspects should be taken into account while choosing a site:

  • Access to the facility is an important factor affecting communication recovery time and equipment maintenance time. Access to facility should be limited in time and for white lists of employees. Access lists must be up to date.If access lists are not up to date, it can be used, for example, by a dismissed employee whose name was not promptly excluded from the lists. Pay attention on the guards and locks in the places where equipment is located to prevent unauthorized access.
  • A dedicated room availability. It is recommended to place data transmission equipment and points of connection to the infrastructure in a dedicated room, closed from external factors. For example, it can be a room with a separate entrance and access for the company employees only or a machine room where the third-party companies equipment is located.
  • Cable route. The site must meet the requirements for the cable route installaion and for access during the operation phase. General requirements adherence for cabling is an important factor in reducing the risks associated with links accessibility, which can be caused by cable damage or connection errors.
  • Power. The site must have connection point to a stable power supply network. In accordance with the company technical policy, a backup line of electric power supply or an uninterrupted power supply system can be organized. Power supplies must be independent, i.e. there should be no single point of failure. For backup power supply systems, it is recommended to implement automatic switching schemes between sources, which will avoid communication interruption in case of the main power supply source failure.
  • Grounding. Proper grounding can significantly reduce the likelihood of wireless devices failing in the case of electromagnetic noises or lightning strikes.
  • Climate systems. Reliable network equipment operation depends on external conditions: the device is guaranteed to function in the specified temperature range, pressure and humidity. The environment influence is random, therefore, in order to maintain stable operation, the specified climatic conditions must be created artificially, it is recommended to install an air conditioner and a heater with the possibility of their automatic on / off. The climate systems in the high-rise part are impossible, therefore, for reliable operation in harsh conditions, devices of the InfiLINK 2x2 / InfiMAN 2x2 families with an extended temperature range can be used. Such devices are equipped with a built-in heater, which turns on when the ambient temperature drops below a set threshold.
  • Links. A network accessibility can be increased due to the backup links installation. Links must be independent, i.e. do not have single points of failure, for example, a wired communication channel can be the main one, and wireless can be the backup one. Realization of fault-tolerant schemes for automatic links redundancy and aggregation using Infinet devices are described in the Link aggregation, balancing and redundancy article. Scenarios with the mobile objects require a different reservation scheme, describer in the Connectivity with mobile objects article.

Organization of auxiliary facility infrastructure

An important factor of a site choosing is the ability to install auxiliary infrastructure elements, which will increase the availability of the communication system. Video surveillance and alarm systems are examples of auxiliary infrastructure. An alarm allows quickly detect an unauthorized access to the object, and a video surveillance system will be useful in investigating incidents.

Equipment installation

Installation work on the site should be guided by the general requirements and company technical policy. Improperly executed installation can cause a violation of the entire network facility availability, the restoration of which may require large time and financial resources.

In order to ensure physical security, make the following settings for the wireless device:

  • turn off the indicator lights on the device, it will increase its stealth;
  • unused ports of wireless devices can be used by an attacker to gain access to the network, therefore, to eliminate the possibility of unauthorized connections, it is recommended to disable unused network interfaces;
  • devices based on the H11 hardware platform support PoE-out function on eth1. An attacker can use it to power third-party equipment. If the PoE-out function is not used, make sure it is disabled.

Facility operation

Installation work quality control is carried out at the stage of object acceptance into service. The acceptance procedure should be performed in accordance with the company technical policy.

Ensuring information security is a continuous process that requires monitoring and response to identified and emerging threats, therefore, it is necessary to carry out preventive maintenance of communication facilities. Depending on the requirements established in the company and the specifics of the network node, the list of preventive measures may vary. A common set of regular jobs includes:

  • facility inspection to make a list of deviations from the technical policy requirements;
  • cleaning on site;
  • periodic testing of backup systems: for links - scheduled work with the main channel turned off, for power systems - scheduled work with the main source turned off (additionally, uninterruptible power supplies and battery capacity testing).

Physical security implementation for device families

Physical security measures

Event / InterfaceInfiLINK 2x2 and InfiMAN 2x2InfiLINK XG and InfiLINK XG 1000Quanta 5
WebCLIWebCLIWeb
Mounting devicesInfiNet Wireless R5000 installationInstallation ProcedureInstallation
LED indication management
-General Commands-General Commands-
Interface Status managementNetwork SettingsIfconfig commandSwitchIfconfig commandSwitch Settings
PoE-out managementNetwork SettingsIfconfig command---
Heater control-Other commands---

Security in radio

Wireless data transmission is performed in a shared environment, which brings a lot of possibilities for attackers. The security measures described below should be applied in a comprehensive manner, since measures protecting from one threat may not be effective against another.

Frequency configuration

The frequency resource is limited, so the frequencies distributing process between wireless systems should be taken comprehensively. Third-party wireless systems operating at the same or adjacent frequencies can affect the link (Figure 3). Usually, such an influence is not malicious, but it should be considered as a threat, since it leads to the link operation failure. Our task is to search and select a frequency channel free of interference. Keep in mind that interference may not be present at the installation stage, but may appear during the wireless system operation.

Following actions can reduce the risks associated with this threat:

  • Search for interference sources: devices of the InfiLINK 2x2 and InfiMAN 2x2 families allow to obtain the MAC addresses of systems operating in the selected frequency channel using the Radio scanner utility, it make possible to identify the source of interference and decide on measures to eliminate its effect on the link.
  • Manual spectrum scan: manual preliminary radio survey of the territory in which the communication system will be deployed. The frequency is selected taking into account the scan data. Infinet devices allow to evaluate the state of the spectrum using the built-in "Spectrum analyzer" utility.
  • Auto spectrum scan: radio survey of the territory in which the communication system is deployed, performed periodically in automatic mode. The frequency channel can be automatically changed in accordance with the scan data. Infinet devices support DFS and iDFS technology (see Dynamic Frequency Selection), which are designed to automatically scan the spectrum.

Figure 3 - An example of a threat in the frequency channel

Even if a frequency channels distribution is coordinated, the problem of mutual interference may persist. That happens due to an out-of-band radiation: a radiation spectrum is not an ideal rectangle. It has side bands that affect adjacent frequency channels. Below are the spectra of communication systems (Figure 4 a-b) which using adjacent frequency channels: in the first case (Figure 4a) the radiation power of the systems is equal and the threat source influence is lower than the communication system sensitivity, in the second case (Figure 4b) the radiation power of the threat source is higher than communication system and the out-of-band level is higher than sensitivity, it will affect the communication system in the interference form.

The automatic transmit power control (ATPC) function can help to reduce the influence of a third-party communication system on the used frequency channels. In case of interference, devices with active ATPC will increase the radiation power and keep the link performance.

The link budget depends also on the used modulation-coding scheme: higher MCS require higher link parameters, therefore, they are impossible to use with a low signal level and a high level of interference. Thus, the modulation-code scheme selection is a compromise between the link performance and reliability. The automatic modulation control (AMC) function allows to select a modulation-coding scheme in accordance with the current parameters of the radio and change it in accordance with the situation. This allows to increase the reliability and availability of information, by keeping the link operability even in strong interference conditions.

For more information about signals frequency characteristics proceed to the online course "Wireless Networking Fundamentals".

Figure 4a - An example of an adjacent frequency channel influence on a communication system

Figure 4b - An example of an adjacent frequency channel influence on a communication system

Authentication Settings

Popular scenarios of the information confidentiality and integrity violation in a radio channel are attacks of the Man-In-The-Middle type (MITM). Let's look at the examples of such attack:

  • Data interception (Figure 5a): the attacker installs a device that receives all transmitted signals in the communication system coverage area. All wireless systems use a shared data transmission medium, so devices receive data even if they are not specified as a recipients. Further, the device processes the frame at the L2 layer, if it is its recipient, or discards it if it is not. An attacker can pretend to be the recipient and gain an access to all messages, along with a legal addressee.
  • Data relay (Figure. 5b): a specific case of the "Data interception" scenario in which an attacker uses a relay instead of a passive receiver. Such an attack option is applicable for example for point-to-point links with a narrow radiation pattern, where the Data Interception scenario is not suitable.
  • Data spoofing (Figure 5c): a specific case of the "Data relay", in which the attacker changes data during relay. In such a scenario, not only confidentiality is violated but data integrity.

Figure 5a - Data interception

Figure 5b - Data relay

Figure 5c - Data spoofing

Also scenarios of obtaining unauthorized access to resources through a connection to a radio network are possible. Let's look at the examples of such attack:

  • Connection to an enterprise network (Figure 6): an attacker with a subscriber device can install it in the base station coverage area. After establishing a link with the base station sector, an attacker can gain access to the enterprise network and implement attacks aimed at integrity, availability and confidentiality violation. An attacker will be able to establish a link with a base station sector only if the Infinet wireless device is used.

Figure 6 - Connection to an enterprise network

  • Base station sector substitution (Figure 7a-b): an attacker installs a base station sector to which a subscriber station can connect. After that the attacker gains unauthorized access to the data originating from the subscriber station and to the network segment behind the subscriber station. Let's look at the example of such attack in scenarios with the mobile objects (see Connectivity with mobile objects). The radio link is established between BS1 and CPE (Figure 7a), the CPE is inttalled on the mobile object and breaks the connection while moving from BS1 and starts to look for a new base station sector to set a connection (Figure 7b). An attacker set a base station sector along the CPE route, between BS1 and BS2, therefore, after disconnecting from BS1, the CPE establishes a connection with the attacker's sector. This attack type implementation is possible only in case of the security settings disregarding.


Figure 7a - Connection of the CPE station to the enterprise base station sector

Figure 7b - Connection of the CPE station to the attacker base station sector

Infinet devices use their own radio frame format, it makes impossible to organize a communication between devices operating according to the 802.11 family standards and Infinet devices. This complicates the attacker's plans, as he will be forced to use Infinet devices.

To counter such attacks, the following options should be used:

  • Link ID: always change the default value to unique.
  • Security key: devices can establish a connection only if they have the same link ID and security key, i.e. to reduce the likelihood of organizing a link with an attacker device, security keys must be installed on both devices.
  • Authentication Mode: InfiLINK 2x2 and InfiMAN 2x2 family devices support authentication mode settings when establishing a wireless link. "Static" and "remote" modes can limit the list of devices with which the link installation is allowed. The static mode allows to set a list of devices MAC addresses with which connection can be established (white list), or a list of addresses with which connection establishment is forbidden (black list). The remote method allows to store MAC addresses for whitelists or blacklists centrally and perform appropriate requests when trying to establish a connection. Using one of the described authorization methods will significantly complicate an unauthorized connection of an attacker to the network.
  • Max links: sets maximum allowed number of connected CPEs. It is recommended to set the value of the actual subscriber stations number.
  • Scrambling: reversible process of redistributing data bits in accordance with a given algorithm in order to equalize the frequency spectrum of the signal. Scrambling also make difficult to decrypt the intercepted data, because the attacker must have the descrambling algorithm used to recover the original bit sequence. Scrambling/descrambling operations will require hardware resources, therefore is recommended to use this option in cases of low hardware load.
  • Frequency grid: the frequencies range supported by the radio module can be deliberately limited using the frequency grid on all Infinet devices. This restriction narrows down the list of frequencies that can be set as central. The frequency grid additional effect is to increase the level of the device protection from choosing a random frequency channel as a operational. If the automatic center frequency selection is set, then the device will select it in accordance with the grid. The center frequency can be set manually: on Master devices, the center frequency is set strictly, on Slave devices, depending on the family, either strictly or using one or more radio profiles. If a subscriber station uses several radio profiles (see Connectivity with mobile objects), then while connecting to the base station sector, profiles will be sorted until a successful connection.
  • Global function: in scenarios with mobile objects, the Global option is used to connect a subscriber station to base stations sectors that are connected to the network core (see Connectivity with mobile objects). This approach can be used to block the CPE connections to base stations sectors installed by attackers (Figure 7b): since the attacker's base station is not connected to the network core, the subscriber station will ignore the attacker device during roaming.

Implementation of strategies for radio link security

Radio link safety measures

MeasuresInfiLINK 2x2 and InfiMAN 2x2InfiLINK XG and InfiLINK XG 1000Quanta 5
WebCLIWebCLIWeb
Spectrum analysisSpectrum AnalyzerMuffer commandSpectrum Analyzer⁣Command for spectrum scanningSpectrum Analyzer⁣
Radio ScannerDevice statusMuffer command---
DFS technology supportLink Settingsdfs (Dynamic Frequency Selection)Radio settingsCommands for modem configurationRadio settings
Instant DFS technology supportLink Settings

mint command in MINT version

mint command in TDMA version
Radio settingsCommands for modem configuration-
DFS/Instant DFS work resultsDFS menu-Instant DFSCommands for modem configuration-
Automatic transmission power controlLink Settings

rfconfig command in MINT version

rfconfig command in TDMA version
Radio settingsCommands for modem configurationRadio settings
Automatic MCS controlLink Settings

rfconfig command in MINT version
rfconfig command in TDMA version

Radio settingsCommands for modem configurationRadio settings
Link IDLink Settings

rfconfig command in MINT version
rfconfig command in TDMA version

Radio settingsCommands for modem configurationGeneral settings
Link security keyLink Settings

mint command in MINT version
mint command in TDMA version

Radio settingsCommands for modem configurationSecurity settings
Authentication mode configurationLink Settings

mint command in MINT version
mint command in TDMA version

---
Lists for static authentication modeStatic Links

mint command in MINT version
mint command in TDMA version

---
Lists for remote authentication mode-

mint command in MINT version
mint command in TDMA version

---
Maximum number of subscriber stationsLink Settings

mint command in MINT version
mint command in TDMA version

---
Scrambling technologyLink Settings

mint command in MINT version
mint command in TDMA version

---
Frequency grid configurationLink Settings

rfconfig command in MINT version
rfconfig command in TDMA version

Radio settingsCommands for modem configurationRadio settings
Central frequency configuration (for Master device)Link Settings

mint command in MINT version
mint command in TDMA version

rfconfig command in MINT version
rfconfig command in TDMA version

Radio settingsCommands for modem configurationRadio settings
Central frequency configuration (for Slave device)Link Settings

mint command in MINT version
mint command in TDMA version

rfconfig command in MINT version
rfconfig command in TDMA version

Radio settingsCommands for modem configurationRadio settings
Regulatory domain----General settings
Global function-

mint command in MINT version
mint command in TDMA version

---

Device management

Unauthorized access to the device management interface is a serious threat that can lead to a violation of all the basic data properties, measures to ensure information security and reduce potential risks should be elaborated carefully.

Authentication and Authorization

CAUTION

By default, one user is added to the configuration with administrative rights and the following login values:

  • login: any nonempty string;
  • password: any nonempty string.

Since the default authentication settings allows a high probability of unauthorized access, change the username and password during initial setup.

A company can have several lines of technical support: in such scheme, some problems that do not require wireless devices reconfiguration can be solved by the first line of technical support. Thus trivial tasks can be solved without qualified employees of the second and third lines of technical support. To implement this scenario, a guest account can be added to the device configuration. A user which has access to the management interface using a guest account can use the utilities and view interface statistics, but he is not allowed to make configuration changes.

It is recommended to use centralized account storage for networks with a large number of devices. This allows to avoid errors when blocking accounts, provide a single password policy and have a single interface for accounts management. Infinet devices support the RADIUS protocol, which is intended for centralized authentication, authorization and account management in networks. Depending on the capabilities and scale of the network, the database for RADIUS operation can be deployed on a separate device, or combined with other network elements.

The algorithm for a RADIUS server usage is following (Figure 8):

  1. Request to access the device management interface: the user tries to access the device management interface using one of the protocols (see below), by forming a request with username and password.
  2. Forming a request to RADIUS server: the device receives a request from the user and generates a request to the server in accordance with the RADIUS protocol.
  3. RADIUS server reply: the RADIUS server receives the request and checks for the presence and rights allocated to the user whose credentials are passed in the request. The server can answer in two ways:
    1. Access is allowed: the account is present in the database and it is allowed access to the Slave device management interface (Figure 8a).
    2. Access is denied: the account is absent in the database, or access to the Slave management interface is denied for this user (Figure 8b).
  4. Device decision making: the device receives a response from the RADIUS server and makes a decisions about the user authorization. In case of successful authorization, the user will go further to the device management interface (Figure 8a), otherwise, the user connection is reset and an information message is displayed.

Figure 8a - An example of successful RADIUS authentication

Figure 8b - An example of unsuccessful RADIUS authentication

Access methods

Infinet devices can be configured using the Web GUI or the command line interface (CLI). Some parameters can only be configured via CLI. Access to different interfaces is carried out using various network protocols. It is recommended to disable unused protocols, to reduce the possibility of unauthorized access to the device management interface.

The management protocols supported by Infinet devices correspond to the management interfaces in a following way:

  • Web GUI:
    • HTTP: data are transmitted over the network unencrypted, so an attacker, gaining access to the network, can intercept them.
    • HTTPS: data are transmitted over the network encrypted, so an attacker who intercepts the data will not be able to decrypt it without the corresponding encryption keys. Unless there are specific reasons for using HTTP, the HTTPS protocol should be used.
  • CLI:
    • Telnet: data are transmitted over the network unencrypted, so an attacker, gaining access to the network, can intercept them. Telnet protocol is acceptable in case of emergency, when there is no possibility of using SSH.
    • SSH: data are transmitted over the network encrypted. In case an attacker intercepts the data he will not be able to decrypt it without the corresponding encryption keys.

Network management interface

The network management interface (mgmt), which used to access the device is organized differently in different device families:

  • InfiLINK XG, InfiLINK XG 1000 and Quanta 5: for device management is allocated internal virtual interface, which can be associated with an IP address.
  • InfiLINK 2x2 and InfiMAN 2x2: an IP address can be associated with virtual or physical interfaces, i.e. various interfaces can act as a network management interface, for example eth0, svi100. Several network management interfaces of the same or different types can be added to the configuration.

In addition to selecting the the management interface, it is also  possible to control the connectivity between the management interface and other network interfaces. This mechanism allows to restrict access to the device via wired or wireless interfaces, depending on the scenario.

Figure 1 demonstrates the scenarios for Infinet devices usage. Let's look at the device management configuration for each scenario. To do this, we have added the PCs connected to different network segments to perform the devices management (Figure 9a-c):

  • Joining of internal network segments: access to the devices management interfaces should be provided to PC users from different network segments (Figure 9a). Wireless devices are located on the internal network and do not directly contact external network devices. The function of protecting against unauthorized access should be performed by network elements located at the border of internal and external networks.
  • Connection of internal and external network segments: access to the device management interface should be granted only to a PC user connected to the local network segment (Figure 9b), i.e. the ability to transfer data between the management interface and the Slave device wired interface should be disabled.
  • Internal network segment connection with Internet: access to the device management interface should be granted only to a PC user connected to the local network segment (Figure 9c). In addition, access may be granted to some PC users connected to the Internet. In this case, incoming traffic filtering must be configured on border devices, as it is shown below.

Figure 9a - Radio link joining internal network segments

Figure 9b - Radio link connecting internal and external network segments

Figure 9c - Radio link connecting internal network segment with Internet

We recommend to use the following principles of management configuration:

  • Use the virtual interface as management:
    • InfiLINK XG, InfiLINK XG 1000 and Quanta 5 family devices: network management interface (mgmt).
    • InfiLINK 2x2 and InfiMAN 2x2 family devices: network interface svi connnected with switch group for management traffic.
  • Access to the management interface should be allowed only through network interfaces, connected to the engineers PC or services that manage devices, for example, a monitoring system.
  • In the case of network traffic isolation using a VLAN, a separate VLAN must be allocated for the management traffic and associated with the management interface.

Access limitation

InfiLINK 2x2, InfiMAN 2x2 and Quanta 5 family devices allows to create white access lists. In this case only network nodes which IP addresses mentioned in the list will be permitted to access the management interface.

Access recovery

ERConsole utility is used to restore an access to all Infinet devices (see the  "ERConsole" screencast). The utility can be used for the following purposes:

  • Error in device configuration: ERConsole utility allows to assign an IP address to the interface, or reset the device to factory settings in case of a fatal errors in configuration.
  • Device protection against an attacker: To reset the Infinet device to the factory settings, a factory password is required, which is assigned to the company that purchased it. If the device is stolen by an attacker, he will not be able to get the factory password from technical support, cause he is not an employee of the enterprise, which means he will not be able to access the device.

Data transmission

Data transmission is the main function of any network equipment. In addition to user data, devices exchange service messages of auxiliary protocols such as SNMP, LLDP, etc. The described functions implementation contains potential threats that an attacker can use, and requires accurate configuration of all wireless devices subsystems.

General recommendations

Wireless systems are hardware and software systems. Therefore, one of the most important requirements is the timely software updating. It is recommended to use stable software versions and monitor the release of updates. Used software version can be checked directly on the device.

When making changes to the devices configuration, keep in mind that the mechanism for applying the settings depends on management interface used:

  • Web GUI: changes made in different sections of the interface are accumulated and sequentially added to the configuration only after clicking the "Apply" button. When the device is rebooted, the last successfully saved configuration will be loaded.
  • CLI: the command is instantly added to the current configuration, but not saved. To save the settings, run the appropriate command. When the device is rebooted, the last successfully saved configuration will be loaded.

In some cases, errors made during the device configuration process can lead to access loss to the device and the device may need to be reset to factory settings (see "Access recovery"). To reduce the risk of this scenario, it is recommended to use a delayed device reboot. In this case, after applying the new configuration, a device availability check will be performed. If the device is unavailable, the previous version of the configuration will be restored.

Service traffic

By default, switching on the device is configured to pass data between the wired and wireless interfaces without filtration. Such scheme is vulnerable to a large amount of spurious traffic, which can take up all the available throughput and the link will actually become inaccessible for the transmission of useful traffic. An example of spurious traffic is a broadcast storm, which can cause errors in devices switching. Measures to protect the network infrastructure from such attacks are:

  • Traffic filtering: a good practice is to split the physical infrastructure into multiple virtual local area networks using VLAN technology. This method allows to limit broadcast domains, and thus reduce the impact of a broadcast storm. This will require traffic filtering of different VLANs on devices: for wireless devices it is recommended to permit only those VLAN tags that really should be transmitted through the radio link and deny all others.
  • STP: Spanning Tree Protocol is designed to prevent link-level loops that could cause a broadcast storm. In addition, the STP protocol can be used to build automatic backup schemes at the L2 layer in networks with redundancy.
  • Router mode: Routing technology can reduce the size of the broadcast segment that will lead to the lower impact of the broadcast storm. A router is a device that divides broadcast domains, i.e. a broadcast storm in one domain will not affect the operation of devices in another. Routing also involves the packets transmission based on the IP header with a TTL field included, which prevents packets from cycling through the network.

Network Protocol Configuration

In addition to user data, devices exchange service messages of auxiliary protocols. The security should take into account that any available service is a potential attacker's target.

DHCP

Infinet devices can be configured as a DHCP client, DHCP server and DHCP relay. Keep in mind that the DHCP protocol supports not only the IP address allocation, but also the network settings transmission.

Let's look at the example of the attack using the DHCP (Figure 10): there is link between the Master and Slave, a DHCP client is activated on the Slave device radio interface and the DHCP server is installed on the corporate network. In this example the attacker managed to connect the network device on which the DHCP server is configured to the corporate network. After the Master-Slave link has been established, the Slave device sends a broadcast request to the network to receive network settings from the DHCP server. DHCP servers located on the network respond to a request from Slave. If the response from the attacker server is received first, the Slave device will assign to the network interface the proposed address and network settings that are transmitted in this request. Thus, an attacker can set his device as the default router and gain access to the traffic transmitted by the Slave device.

Figure 10 - An example of the attack using the DHCP

An attacker’s device can also act as a DHCP client (Figure 11): the functions of network DHCP server are implemented on Infinet device,  an attacker’s device is connected to the network. In a situation where the DHCP server configuration protocol does not provide security measures, the attacker will generate a request and the server will provide the device with network details. Thus, an attacker will gain access to data transmitted over the network.

Figure 11 - An example of the attack using the DHCP

In order to increase the security of using DHCP in the corporate network, it is recommended to implement the following measures:

  • DHCP servers list limitation by DHCP client: The DHCP client allows to limit the list of servers for which a network settings request will be generated. In this case, the DHCP client will generate requests for the specified DHCP servers, if they do not respond, it will generate a broadcast request.
  • Security key usage: a security key can be used during the client authentication. Keep in mind that this setting must be performed both on the DHCP server and on the DHCP client.
  • Client-address pair in a DHCP server configuration: the DHCP server configuration allows to record the IP addresses allocated to clients. Thus, it is possible to create white lists of devices, so the obtaining network details will become complicated for an attacker.
  • DHCP Snooping: this technology allows to prevent receiving network details from the attacker's DHCP server. The operation principle is very simple: the Ethernet ports, behind which the DHCP server is located, are marked as trusted, the rest as untrusted. Messages from DHCP servers that arrived at the untrusted ports will be discarded, which makes impossible for client devices to obtain network details from the attacker server.
  • Disable DHCP on unused interfaces: the list of interfaces on which DHCP is enabled should be carefully monitored. Disable DHCP on interfaces that are not used for data transfer or use static addressing. This recommendation is actual for both the DHCP client and server.
  • Refuse of DHCP: keep in mind that the DHCP usage must be limited, a lot of scenarios require the static assignment of network details to the corresponding interfaces. For example, it is recommended to assign static addresses to key network elements, which may include Infinet wireless devices. This will help to avoid problems in organizing technical accounting and monitoring systems.
ARP

Ethernet and IP protocols belong to different levels of the network interaction model, to bind the addresses of devices used in each of the protocols a special tool is needed. ARP protocol and the address mapping table that it fills are used for this purpose. The table contains entries where the MAC address of the interface is mapped to the IP address, that is used when transmitting IP packets encapsulated in Ethernet frames.

Let's look at the example of an attack with IP address spoofing: two clients (Client 1 and Client 2) have an access to the Internet via the Master-Slave radio link. An IP address assigned to the client is an identifier for the appointment of a tariff plan. The client with the IP address 192.168.0.1 is provided with a throughput of 10 Mbit/s, the client with the address 192.168.0.2 - with 2 Mbit/s (Figure 12a). At some point Client 1 turns off the PC and does not use the provider services, at the same time Client 2 replaces its IP address with the 192.168.0.1 address assigned to Client 1 (Figure 12b). In this case Client 2 will gain access to the Internet with greater throughput, and Client 1 after switching on, will have problems with access to the network.

Figure 12a - An example of the attack using IP spoofing

Figure 12b - An example of the attack using IP spoofing

This type of attacks with IP address spoofing can be prevented by adding a static record to the ARP protocol address mapping table. In this case Client 2 data will not be transmitted after changing the IP address, because the address 192.168.0.1 will be assigned the MAC address of Client 1.

LLDP

The LLDP protocol is designed to exchange service information about a device with directly connected devices. The service information is the VLAN ID, MAC address, device name, IP address of the management interface, etc. If an attacker will gain physical access to the device, then by launching the LLDP service on his PC, he will be able to get service information about the device by exchanging service messages (Figure 13). This information can help to get unauthorized access to the device.

To prevent this type of attack, follow the guidelines:

  • Global LLDP disabling: if technical policy of the company does not require the LLDP usage, it is recommended to disable its operation on all network devices.
  • LLDP disabling on interfaces: if it is necessary to use LLDP, then it should be allowed only on those network interfaces to which network infrastructure elements are connected.
Figure 13 - An example of the attack using LLDP
SNMP

SNMP was created as a unified protocol for managing network devices and collecting data on their state. The protocol provides for two types of requests: a request to GET some parameter value and a request to SET the parameter specified value. Thus, devices that support SNMP can operate in read mode (only GET requests) and write mode (SET and GET requests). SNMP server activation is necessary for centralized device management by a monitoring system. But an attacker could take his chance if the SNMP server is not configured properly. In this case, he can not only get information about the network structure, but also change the configuration of the device (Figure 14).

To prevent unauthorized access follow the guidelines:

  • SNMPv3: by default, SNMPv1 and SNMPv2c support is activated on devices, a community with name "public" is created. The SNMPv1 and SNMPv2c protocols provide authentication using the community name, which is openly transmitted over the network. SNMPv3 is recommended to use due to implementation of authentication and message encryption.
  • Read only mode: if SNMP SET mode is not used, then its support must be disabled. This will reduce the potential consequences of unauthorized access.
  • White lists: Infinet devices allow to create white lists of access to the SNMP server.

Figure 14 - An example of the attack using SNMP

MINT

MINT is the proprietary Infinet protocol, whose operation can be organized in the wired and wireless segments. An attacker, gaining access to the MINT domain, can compromise all network devices related to this domain, therefore, pay special attention while configure the MINT protocol.

Let's look at the example of an attack using the MINT protocol: two wireless links Master 1 - Slave 1 and Master 2 - Slave 2 are joined into the MINT area using PRF interfaces (Figure 15a). The attacker get physical access to the enterprise network using the InfiMUX switch, on which the PRF interface is created (Figure 15b). PRF interfaces will establish communication channels between each other and all devices will be combined into a MINT area, so an attacker will receive information about devices in this area and will be able to execute remote commands on them using MINT tools.

Protection against such attacks:

  • Security key: PRF interface is a virtual radio interface operating in a wired environment, therefore, same as for wireless interface, the PRF interface supports the ability to install a security key. In this case, the link between two PRF interfaces will be organized only if their security keys match.
  • Password for remote commands execution: one of the MINT protocol tools is the ability to remotely execute commands on a device located in the same MINT area. By default, remote command execution is available without a password, set the password to limit the capabilities of the attacker.

Figure 15a - Joining links in the MINT area

Figure 15b - An example of the attack using MINT protocol


Infrastructure

Infrastructure security is the important section of information security, which needs a special attention. Infrastructure character depends on the technical policy of the enterprise. The network should contain logging, monitoring and technical record-keeping.

Monitoring

A monitoring system is required for centralized device management and network operation monitoring. Also, the monitoring system sends notifications to engineers if the parameter values are outside the allowed range. Such notifications reduce the service personnel response time, thereby minimize the consequences of failures and possible attacks.

Monitoring systems can be integrated with alarm systems and video surveillance.

Infinet company provides its own system for monitoring Infinet wireless devices - InfiMONITOR. The monitoring system collects data in the following ways (Figure 16):

  • Polling: the monitoring system sends SNMP requests to the device demanding the parameters whose values must be received. The device generates an SNMP response for the monitoring system, where it indicates the values of the requested parameters. Device parameters polling is carried out with a set periodicity, which guarantees each device will be requested in a given interval.
  • Traps: the device sends a special SNMP Trap message to the monitoring server in case of an incident from the specified list. SNMP Trap sending is initiated by the device itself and occurs instantly, regardless of the polling cycle, however, this will require additional device configuration.

Figure 16 - Data exchange between devices and a monitoring system

Syslog storage

A detailed incident investigation requires an analysis of the system logs stored on the device. Infinet devices support logging, but the system log will be lost after a device reboot. In large networks it is useful to have a centralized repository of log files, such repository has an interface which allows to display all network devices logs used in incident investigation.

A Syslog server is allocated on the network for these purposes. All log entries are sent to the Syslog server simultaneously with writing to the system log (Figure 17). This allows to store the all network devices message history centrally without risk to lose all syslog data in case of device reboot or unauthorized access.

Figure 17 - Data exchange with the Syslog server

Technical record-keeping

Operational problems solving, to gain access to the facility, restore the configuration, add it to the monitoring system, etc requires a comprehensive information about devices. Such information includes both technical and administrative aspects. Special technical record-keeping systems can be used on the network to store the data and have access to it. Technical record-keeping systems contain the following information:

  • Device info: indicates the device model, its serial number and network details.
  • Site info: indicates the device location, information about access to the site, contact information, etc.
  • Text device configuration: The the device configurations history can be used for the incident investigation and device operation restore, therefore, configurations backups should be performed regularly. Some technical record-keeping systems can be joined with systems of mass devices configuration on the network: such systems allow to unifiy devices configurations, and the network is assumed as a single device for which the history of changes is stored.

Infrastructure security measures implementation for devices families

Infrastructure security measures

Additional materials

Online courses

  1. InfiLINK 2x2 / InfiMAN 2x2: Initial Link Configuration and Installation.
  2. InfiLINK XG Family Product.
  3. Quanta 5: Installation and Configuration.
  4. Wireless Networking Fundamentals.
  5. InfiLINK 2x2 and InfiMAN 2x2: Switching.

White papers

  1. Link aggregation, balancing and redundancy.
  2. Connectivity with mobile objects.

  3. Dynamic Frequency Selection.

Webinars

  1. InfiNet Wireless equipment installation, grounding and lightning protection.
  2. Switching configuration using InfiNet Wireless devices - typical scenarios.
  3. Link diagnostics for the InfiLINK 2x2 and InfiMAN 2x2 product families.
  4. InfiNet Wireless solutions for mobile projects.

Screencast

  1. InfiNet Wireless Equipment - From Planning to Commissioning.
  2. ERConsole.

Other

  1. Acessories section on the infinetwireless.com
  2. FTP Infinet Wireless
  3. InfiMONITOR section on the infinetwireless.com
  • No labels