Authentication Issues between   entities during protocol message exchange in SCADA           Systems  Manuel Humberto Sant...
Agenda•   Introduction•   SCADA protocols•   Authentication Risks•   Remediation
SCADA• Supervisory Control and Data  Acquisition• Platform used to monitor and control all  the variables of a real-time p...
Components of SCADA platform
Components of SCADA platform (2)• Remote Terminal Unit (RTU):  – This is a communication device within the    SCADA system...
Components of SCADA platform (3)• Data Acquisition System (DAS):  – Gathers information from the MTU  – Generates and stor...
Components of SCADA platform (4)• Master Terminal Unit (MTU):  – MTU   initiates  communication  with    remote units and ...
Electrical process• Three big steps  – Generation  – Transmission  – Distribution• Energy is created using any of the  fol...
Electrical process (2)• SCADA platform is vital to perform  the following when generation takes  place:  – Ensure    turbi...
Electrical process (3)• Transmission  – Energy being generated needs to be    distributed to reach the final users  – 115 ...
Electrical process (4)• SCADA platform is vital to perform  the following when transmission  takes place:  – Monitoring of...
Electrical process (5)• Distribution  – Energy being generated needs to be    distributed to reach the final users  – 115 ...
Electrical process (6)• SCADA platform is vital to perform  the following when distribution takes  place:  – Monitoring of...
Agenda•   Introduction•   SCADA Protocols•   Authentication Risks•   Remediation
SCADA Protocols• Modbus• IEC 104• DNP3
Modbus         Source:  Practical   Industrial   Data         Communications
Modbus (2)• Client/server protocol which operates in a  request/response mode• Three variants:  – Modbus serial RS-232/RS-...
Modbus (3)      Source:  Practical   Industrial   Data      Communications
Modbus (4)• Modbus protocol structure  – Address field:     • Request frames: Address of the device being targeted       b...
Modbus (5)• Modbus protocol structure  – Function field     • Function requested by the HMI to be performed by the       f...
Modbus (6)                                                                                  Function                      ...
Modbus (7)                                                  Function                             Function Name        Type...
Modbus (8)• Modbus protocol structure  – Data field     • In request paquets, contains the information required       to p...
Modbus (9)• Modbus protocol structure  – Error check Field     • CRC-16 on the message frame     • If packet has errors, t...
IEC 104• Standard for power system monitoring,  control and communications for telecontrol  and teleprotection for electri...
IEC 104 (2)• It has the following features:  – Supports master initiated messages and    master/slave initiated messages  ...
IEC 104 (3)              Source: Practical              Industrial Data              Communications
IEC 104 (4)              Source: Practical              Industrial Data              Communications
IEC 104 (5)              Source: Practical              Industrial Data              Communications
IEC 104 (6)• Link level      Link service          class           Function         Explanation                           ...
IEC 104 (7)              Source: Practical              Industrial Data              Communications
IEC 104 (8)• Control field for unbalanced transmissions                                      Source: Practical            ...
IEC 104 (8)• Control field for balanced transmissions                                       Source: Practical             ...
DNP3• Set of communication protocols used between  components of a SCADA system• Used for communications between RTU and  ...
DNP3 (2)• Enhance performance architecture (EPA)                                    Source: Practical                     ...
DNP3 (3)• Message exchange                     Source: Practical                     Industrial Data                     C...
DNP3 (4)• Frame format                 Source: Practical                 Industrial Data                 Communications
DNP3 (5)• Control Byte                 Source: Practical                 Industrial Data                 Communications
Agenda•   Introduction•   SCADA Protocols•   Authentication Risks•   Remediation
Network technologies in SCADA Systems• Many SCADA networks still use  RS232/RS485 bus to communicate  all components  – Bu...
Lack of authentication in applicationprotocol• The SCADA protocols does not  perform bi-directional authentication  to ens...
Lack of confidentiality in applicationprotocol• The SCADA protocols does not perform  any   encryption  to   protect    th...
What could be done?• Let’s see how a master station puts  the current timestamp on an IED• Let’s see how the attacker chan...
Agenda•   Introduction•   SCADA Protocols•   Authentication Risks•   Remediation
What you cannot do with SCADA• Protocol delay is usually a BIG issue in  SCADA  – Water supply and Oil SCADA tolerates big...
SCADA Network Design
Monitor your network• SCADA traffic baseline is mandatory  – You need to know what applications are    doing transit insid...
Monitor your network (2)• Use   Network        Intrusion      Prevention  System  – You definitely can use conventional IP...
Control unauthorized changes to MasterTerminal Unit• SCADA platforms are designed to  last from 10 to 20 years – Too many ...
Control unauthorized changes to MasterTerminal Unit (2)• SCADA platforms are designed to  last from 10 to 20 years – Too m...
Control unauthorized changes to MasterTerminal Unit (3)• Control any changes       inside   your  SCADA servers  – Mcafee ...
Monitor attacks to Master Unit• Host IPS is definitely needed as any  attack could change the integrity and  stability of ...
Monitor attacks to Master Unit (2)• Industrial Defender Host IPS works  pretty good• Works     seamless    with    Siemens...
Questions? Comments?   Manuel Humberto Santander Peláez          http://manuel.santander.name       http://twitter.com/man...
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Authentication Issues between entities during protocol message exchange in SCADA Systems

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Authentication Issues between entities during protocol message exchange in SCADA Systems

  1. 1. Authentication Issues between entities during protocol message exchange in SCADA Systems Manuel Humberto Santander Peláez msantand@isc.sans.org
  2. 2. Agenda• Introduction• SCADA protocols• Authentication Risks• Remediation
  3. 3. SCADA• Supervisory Control and Data Acquisition• Platform used to monitor and control all the variables of a real-time process• Several variables to monitor – Pressure inside a water tube used for distribution – Flow speed of oil – Amount of electric charge passing inside an electricity transmission line
  4. 4. Components of SCADA platform
  5. 5. Components of SCADA platform (2)• Remote Terminal Unit (RTU): – This is a communication device within the SCADA system and is located at the remote substation. – The RTU gathers data from field devices in memory until the MTU request that information. It also process orders from the SCADA like switch off a transmission line – It process the commands ordered by the HMI to the field devices
  6. 6. Components of SCADA platform (3)• Data Acquisition System (DAS): – Gathers information from the MTU – Generates and store alerts that needs attention from the operator because it can cause impact on the system• Master Terminal Unit (MTU): – The MTU is defined as the heart of a SCADA system and is located at the main monitoring center.
  7. 7. Components of SCADA platform (4)• Master Terminal Unit (MTU): – MTU initiates communication with remote units and interfaces with the DAS and the HMI.• Human Machine Interface (HMI): – Interface where the operator logs on to monitor the variables of the system. – Gathers information from the DAS – Sends commands to the MTU and wait for response
  8. 8. Electrical process• Three big steps – Generation – Transmission – Distribution• Energy is created using any of the following methods – Thermoelectrical plans – Nuclear plants – Hydro electrical plants
  9. 9. Electrical process (2)• SCADA platform is vital to perform the following when generation takes place: – Ensure turbines are not having revolutions more than supported – Generators are not working overloaded – Energy being generated matches the amount of energy that the transmission line can handle
  10. 10. Electrical process (3)• Transmission – Energy being generated needs to be distributed to reach the final users – 115 KV is the power used to transmit in the wire lines – Final destination are the substations that handles energy of a specific amount of instalations – Large number of blocks in a city
  11. 11. Electrical process (4)• SCADA platform is vital to perform the following when transmission takes place: – Monitoring of voltage in transmission lines looking for high amount of electricity flowing – None of them can get overloaded because protections get activated and a blackout appears in all the installations that are controlled by the affected substations
  12. 12. Electrical process (5)• Distribution – Energy being generated needs to be distributed to reach the final users – 115 KV is the power used to transmit in the wire lines – Final destination are the substations that handles energy of a specific amount of instalations – Large number of blocks in a city
  13. 13. Electrical process (6)• SCADA platform is vital to perform the following when distribution takes place: – Monitoring of voltage in transmission lines looking for high amount of electricity flowing – Monitoring of voltage in user meters looking for high amount of electricity flowing
  14. 14. Agenda• Introduction• SCADA Protocols• Authentication Risks• Remediation
  15. 15. SCADA Protocols• Modbus• IEC 104• DNP3
  16. 16. Modbus Source: Practical Industrial Data Communications
  17. 17. Modbus (2)• Client/server protocol which operates in a request/response mode• Three variants: – Modbus serial RS-232/RS-485: Implemented on serial networks – Modbus TCP: Used for SCADA platforms where delay is not an issue (Water supply) – Modbus UDP: Used for SCADA platforms where delay is a big issue (Energy)
  18. 18. Modbus (3) Source: Practical Industrial Data Communications
  19. 19. Modbus (4)• Modbus protocol structure – Address field: • Request frames: Address of the device being targeted by the request • Response frame: Address of the device responding to request
  20. 20. Modbus (5)• Modbus protocol structure – Function field • Function requested by the HMI to be performed by the field devices • In response packets, when the function performed is succeeded, the field device echoes it. If some exception occurred, the most significant bit of the field is set to 1
  21. 21. Modbus (6) Function Function Name Type of access Code Physical Discrete Inputs Read Discrete Inputs 2 Read Coils 1 Bit access Internal Bits or Physical Write Single Coil 5 Coils Write Multiple Coils 15 Physical Input Registers Read Input Register 4 Read Holding Registers 3 Write Single Register 6 Data Access 16-bit Write Multiple Registers 16 Internal Registers or access Physical Output Registers Read/Write Multiple 23 Registers Mask Write Register 22 Read FIFO Queue 24 Read File Record 20 File Record Access Write File Record 21
  22. 22. Modbus (7) Function Function Name Type of access Code Read Exception Status 7 Diagnostic 8 Get Com Event Counter 11 Diagnostics Get Com Event Log 12 Report Slave ID 17 Read Device 43 Identification Encapsulated Interface Other 43 Transport
  23. 23. Modbus (8)• Modbus protocol structure – Data field • In request paquets, contains the information required to perform the specific function • In response packets, contains the information requested by the HMI
  24. 24. Modbus (9)• Modbus protocol structure – Error check Field • CRC-16 on the message frame • If packet has errors, the field device does not process it • Timeout is assumed, so the master sends again the packet to attempt again a function execution
  25. 25. IEC 104• Standard for power system monitoring, control and communications for telecontrol and teleprotection for electric power systems• Completely compatible with: – IEC 60870-5-1: Transmission frame formats for standard 60870-5 – IEC 60870-5-5: Basic application functions
  26. 26. IEC 104 (2)• It has the following features: – Supports master initiated messages and master/slave initiated messages – Facility for time sinchronization – Possibility of classifying data being transmitted into 16 different groups to get the data according to the group – Cyclic and spontaneous data updating schemes are provided.
  27. 27. IEC 104 (3) Source: Practical Industrial Data Communications
  28. 28. IEC 104 (4) Source: Practical Industrial Data Communications
  29. 29. IEC 104 (5) Source: Practical Industrial Data Communications
  30. 30. IEC 104 (6)• Link level Link service class Function Explanation Transmit message. No ACK or answer S1 SEND / NO REPLY required Transmit message. S2 SEND / CONFIRM ACK required Transmit message. ACK and answer S3 REQUEST / RESPOND required
  31. 31. IEC 104 (7) Source: Practical Industrial Data Communications
  32. 32. IEC 104 (8)• Control field for unbalanced transmissions Source: Practical Industrial Data Communications
  33. 33. IEC 104 (8)• Control field for balanced transmissions Source: Practical Industrial Data Communications
  34. 34. DNP3• Set of communication protocols used between components of a SCADA system• Used for communications between RTU and the IED (field devices)• Implements the communication levels established by the enhance performance architecture (EPA)
  35. 35. DNP3 (2)• Enhance performance architecture (EPA) Source: Practical Industrial Data Communications
  36. 36. DNP3 (3)• Message exchange Source: Practical Industrial Data Communications
  37. 37. DNP3 (4)• Frame format Source: Practical Industrial Data Communications
  38. 38. DNP3 (5)• Control Byte Source: Practical Industrial Data Communications
  39. 39. Agenda• Introduction• SCADA Protocols• Authentication Risks• Remediation
  40. 40. Network technologies in SCADA Systems• Many SCADA networks still use RS232/RS485 bus to communicate all components – But also because of the need to access data in a fast way, we also have serial-to- ip gateways to access serial RTU and IED – Lots of hybrid SCADA networks having serial and IP components – Vulnerable from outsiders at the corporate network
  41. 41. Lack of authentication in applicationprotocol• The SCADA protocols does not perform bi-directional authentication to ensure that all parties are trusted – Only commands are sent – Data is sent to the IP address configured as master – All the IP spoofing vulnerabilities works on any MTU or Field device – Any command can be sent
  42. 42. Lack of confidentiality in applicationprotocol• The SCADA protocols does not perform any encryption to protect the information – Modbus, IEC 101/104 and DNP3 transmissions can be checked by any attacker – Man-in-the-middle can be performed on the network – MTU traffic can be intercepted and then redirected to any IED with any desired change – No way to know if traffic is trusted
  43. 43. What could be done?• Let’s see how a master station puts the current timestamp on an IED• Let’s see how the attacker changes it• Can issue writable commands and reading commands• DEMO TIME!
  44. 44. Agenda• Introduction• SCADA Protocols• Authentication Risks• Remediation
  45. 45. What you cannot do with SCADA• Protocol delay is usually a BIG issue in SCADA – Water supply and Oil SCADA tolerates big delays because it does not have consequences in the process – Power SCADA is critical. A delay higher than 5 miliseconds could end in a massive blackout because of failure to open a breaker in a substation – Be careful on what you do to protect your SCADA
  46. 46. SCADA Network Design
  47. 47. Monitor your network• SCADA traffic baseline is mandatory – You need to know what applications are doing transit inside your network – Inside SCADA protocols you monitor applications that gives you information on the industrial process being controlled – Unauthorized applications could indicate a breach trying to perform operations or gather information on IED
  48. 48. Monitor your network (2)• Use Network Intrusion Prevention System – You definitely can use conventional IPS if they are fast enough to avoid delays in your network – Not all of them support SCADA protocols – If you have snort, you can write rules for Modbus and DNP3. Otherwise, you need to write your own rules – Industrial Defender Solution works pretty good as it includes lots of SCADA signatures
  49. 49. Control unauthorized changes to MasterTerminal Unit• SCADA platforms are designed to last from 10 to 20 years – Too many technology changes happens in that time – Lots of security issues to deal with – Need a solution to avoid any changes inside computers, as intrusions perform changes in filesystem, configurations and system process
  50. 50. Control unauthorized changes to MasterTerminal Unit (2)• SCADA platforms are designed to last from 10 to 20 years – Too many technology changes happens in that time – Lots of security issues to deal with – Need a solution to avoid any changes inside computers, as intrusions perform changes in filesystem, configurations and system process
  51. 51. Control unauthorized changes to MasterTerminal Unit (3)• Control any changes inside your SCADA servers – Mcafee Integrity control works pretty good – Defines what can be changed by who – Lots of custom logs to choose from – Can send events to any SIEM configured in the Network
  52. 52. Monitor attacks to Master Unit• Host IPS is definitely needed as any attack could change the integrity and stability of a process• Availability is critical to a SCADA system and cannot be altered• Conventional Host IPS performs extensive use of CPU and can affect performance inside SCADA
  53. 53. Monitor attacks to Master Unit (2)• Industrial Defender Host IPS works pretty good• Works seamless with Siemens Spectrum Platform• Does not load the machine or needs extensive bandwith to perform its checks• Central console to perform operations inside the platform
  54. 54. Questions? Comments? Manuel Humberto Santander Peláez http://manuel.santander.name http://twitter.com/manuelsantander msantand@isc.sans.org / manuel@santander.name

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