SYSTEM FOR FINDING POTENTIAL ORIGINS OF SPOOFED INTERNET PROTOCOL ATTACK TRAFFIC

• US 20130028259A1
• Filed: 01/27/2012
• Published: 01/31/2013
• Est. Priority Date: 04/05/2005
• Status: Active Grant

• Current Assignee: PacSec3, LLC (Pueblo Nuevo LLC)
• Original Assignee: Donald N. Cohen, Krishnamurthy Narayanaswamy
• Inventors: Cohen, Donald N., Narayanaswamy, Krishnamurthy
• Granted Patent: US 8,806,634 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 2463/146 Tracing the source of attacks
• CPC Class Codes: H04L 63/0227 Filtering policies mail message filtering H04L51/212
• CPC Class Codes: H04L 63/1408 by monitoring network traffic monitoring network traffic per se H04L43/00
• CPC Class Codes: H04L 63/1441 Countermeasures against malicious traffic countermeasures against attacks on cryptographic mechanisms H04L9/002

Abstract

The invention computes approximate origins of data packets transmitted over the Internet. Law enforcement agencies and network operators can use it to assign responsibility for observed Internet activities. The invention uses a small number of cooperative locations (incoming links on routers or switches) to provide link identification data: whether a packet or did or did not traverse that location. The system uses these cooperative places to generate the link signature of a data packet—which cooperative locations observed and did not observe the packet. Potential origin locations are divided into pre-computed blocks that have the same link signatures to given destination locations. The blocks are used to generate reverse routing data, potential source addresses for different link signatures. Variations of the invention store relevant link identification and reverse routing data to find the origins of past packets or to compute the origins of packets from partial information about packets of interest.

Claims

1. A system for identifying a set of potential origins of Internet Protocol data packets on a network by a computer, said system comprising:

a plurality of cooperating locations on said network, said cooperating locations providing accurate and reliable information as to whether an identified data packet did or did not pass through said cooperating locations at an identified point in time;

a plurality of non-cooperating locations on said network, said non-cooperating locations receiving and transmitting data packets yet providing no or false information as to whether an identified data packet did or did not pass through said cooperating locations at an identified point in time;

a link signature for each of said identified data packets, said link signature comprising a string of digits including a plurality of first predetermined values for each cooperating location through which said packet did pass and a plurality of second predetermined values for each cooperating location through which said packet did not pass;

a means for querying each of said cooperating locations as to whether an identified data packet did or did not pass through said cooperating locations at an identified point in time and calculating said link signatures; and

a table of origins, said table comprising identified destination locations, unions of all link signatures matching data packet information available for said identified data packet and origin locations consistent with said link signatures;

whereby, when a system user supplies a destination location and data packet information regarding an identified data packet, said system will identify the set of possible origins for said data packet.

2. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 1, further comprising:

a sub-system for dividing said locations into blocks, where such blocks comprise said cooperating locations that have identical link signatures for routing a packet to any location from another identified block at said identified point in time; and

a reverse routing table, said table comprising link signatures identifying at least one valid routing between selected locations in each destination/source pair of blocks in said network for said identified point in time;

whereby, when said locations in said network are divided into said blocks, the set of possible origins of identified packets is more easily determined for very large networks.

3. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 2, wherein said table of origins comprises blocks having identified destination locations within them, unions of all link signatures matching data packet information available for said identified data packet and origin locations consistent with said link signatures in said reverse routing table.

4. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 1, wherein said cooperating locations comprise routers or switches on said network.

5. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 1, wherein said first predetermined values are either of ‘

1’ and

‘

true’ and

said second predetermined values are either of ‘

0’ and

‘

false.’

6. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 1, wherein said link signature for each identified data packet is gathered and maintained over a period of time, thereby permitting historical inquiries of said system.

7. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 2, wherein said link signatures identifying all possible valid routings between a selected cooperating location in each destination/source pair of blocks in said network for said reverse routing table are gathered using a system comprising:

an identified destination location in each block;

an identified responding source location in each block;

a probe packet;

said probe packet causing said source blocks to send an identifiable response packet to each of said destination locations in said destination blocks;

a link signature for each destination/source pair of locations derived from information returned by said identifiable response to said probe packet;

an assignment of each of said derived link signatures as link signatures indicating valid routing to all destination locations within said block from all potential source locations within any other block; and

whereby, the link signature derived from said identifiable response to said probe packet is recognized as being one of those that could be observed for packets forwarded from said given source block to said given destination block at a given point in time.

8. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 2, wherein said link signatures in said reverse routing table are gathered and maintained over a period of time, thereby permitting historical inquiries of said table.

9. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 2, wherein definitions of said blocks are updated as new link signature information related to locations within said blocks is received, thereby maintaining said blocks as groups of locations having identical link signatures for routing a packet to an identified location at said identified point in time.

10. The system for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 1, further comprising tools for collecting and storing information at cooperating locations related to data packets passing through said cooperating locations over identified periods of time, said information comprising at least link signature and routing information related to said packets, thereby providing further means for identifying potential origins for data packets based upon partial packet information.

11. A method for identifying a set of potential origins of Internet Protocol data packets on a network having cooperating locations and non-cooperating locations, by a computer said method comprising the steps of:

identifying a plurality of cooperating locations and non-cooperating locations in said network, said cooperating locations providing accurate and reliable information as to whether an identified data packet did or did not pass through each cooperating location at an identified point in time;

said non-cooperating locations receiving and transmitting data packets yet providing no or false information as to whether an identified data packet did or did not pass through each non-cooperating location at an identified point in time;

creating a link signature for each of said identified data packets, said link signature comprising a string of digits including a plurality of first predetermined values for each cooperating location through which said packet did pass and a plurality of second predetermined values for each cooperating location through which said packet did not pass;

querying each of said cooperating locations as to whether an identified data packet did or did not pass through said cooperating locations at an identified point in time calculating said link signatures from data collected from each of said cooperating locations;

developing a table of origins, said table comprising identified destination locations, unions of all link signatures matching data packet information available for said identified data packets and origin locations consistent with said link signatures;

allowing a system user to supply a destination location and data packet information regarding an identified data packet; and

performing computations to identify said set of possible origins for said data packet.

12. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 11 for a very large network, comprising the further steps of:

dividing said locations into blocks, where such blocks comprise locations that have identical link signatures for routing a packet to any location from another identified block at said identified point in time; and

creating a reverse routing table, said table comprising link signatures identifying at least one valid routing between selected locations in each destination/source pair of blocks in said network for said identified point in time.

13. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 12, comprising the further step of:

developing a table of origins wherein said table of origins comprises blocks having identified destination locations within them, unions of all link signatures matching data packet information available for said identified data packet and origin locations consistent with said link signatures in said reverse routing table.

14. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 11, wherein said cooperating locations comprise routers or switches on said network.

15. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 11, wherein said first predetermined values are either of ‘

1’ and

‘

true’ and

said second predetermined values are either of ‘

0’ and

‘

false.’

16. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 11, comprising the further step of gathering and maintaining said link signature for each identified data packet over a period of time, thereby permitting historical inquiries of said system.

17. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 12, wherein said method of developing link signatures identifying all possible valid routings between a selected cooperating location in each destination/source pair of blocks in said network for said reverse routing table comprises the further steps of:

identifying a destination location in each block;

identifying a responding source location in each block;

sending a probe packet to responding locations in each of said source blocks;

said probe packet causing said source blocks to send an identifiable response packet to each of said destination locations in said destination blocks;

creating a link signature for each for each destination/source pair of locations derived from information returned by said identifiable response to said probe packet; and

making an assignment of each said derived link signatures as link signatures indicating valid routing for all destination locations within said block to all potential source locations within any other block;

whereby, the link signature derived from said identifiable response to said probe packet is recognized as being one of those that could be observed for packets forwarded from said given source block to said given destination block at a given point in time.

18. The method for identifying a set of potential origins of Internet data packets on a network, as described in claim 12, comprising the further steps of gathering and maintaining said link signatures in said reverse routing table over a period of time, thereby permitting historical inquiries of said table.

19. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 12, comprising the further step of updating definitions of said blocks as new link signature information related to cooperating locations within said blocks is received, thereby maintaining said blocks as groups of locations having identical link signatures for routing a packet to an identified location at said identified point in time.

20. The method for identifying a set of potential origins of Internet Protocol data packets on a network, as described in claim 11, comprising the further step of collecting and storing information at cooperating locations related to data packets passing through said cooperating locations over identified periods of time, said information comprising at least link signature and routing information related to said packets, thereby providing further means for identifying potential origins for data packets based upon partial packet information.