Automatic virtual private network internet snoop avoider

[0002] This application relates to U.S. patent application Ser. No. 09/428,401, still pending, entitled “Manual Virtual Private Networking Internet Snoop Avoider”, filed contemporaneously herewith.

[0003] The present invention relates in general to networked data processing systems, and in particular to virtual private network (VPN) systems and other network systems using tunneling or encapsulating methods.

[0004] A virtual private network (VPN) is an extension of a private intranet network across a public network, such as the Internet, creating a secure private connection. This effect is achieved through an encrypted private tunnel, as describe below. A VPN securely conveys information across the Internet connecting remote users, branch offices, and business partners into an extended corporate network.

[0005] Tunneling, or encapsulation, is a common technique in packet-switched networks. A packet from a first protocol is “wrapped” in a second packet from a second protocol. That is, a new header from a second protocol is attached to the first packet. The entire first packet becomes the payload of the second one. Tunneling is frequently used to carry traffic of one protocol over a network that does not support that protocol directly. For example, a Network Basic Input/Output System (NetBIOS) or Internet Packet Exchange (IPX) packet can be encapsulated in an Internet Protocol (IP) packet to carry it over a Transmission Control Protocol/Internet Protocol (TCP/IP) network. If the encapsulated first packet is encrypted, an intruder or hacker will have difficulty figuring out the true destination address of the first packet and the first packet's data contents.

[0006] The use of VPNs raises several security concerns beyond those that were present in traditional corporate intranet networks. A typical end-to-end data path might contain several machines not under the control of the corporation, for example, the Internet Service Provider (ISP) access computer, a dial-in segment, and the routers within the Internet. The path may also contain a security gateway, such as a firewall or router, that is located at the boundary between an internal segment and an external segment. The data path may also contain an internal segment which serves as a host or router, carrying a mix of intra-company and inter-company traffic. Commonly, the data path will include external segments, such as the Internet, which will carry traffic not only from the company network but also from other sources.

[0007] In this heterogeneous environment, there are many opportunities to eavesdrop, to change a datagram's contents, to mount denial-of-service (DOS) attacks, or to alter a datagram's destination address. Current encryption algorithms are not perfect, and even encrypted packets can be read given sufficient time. The use of a VPN within this environment gives a would-be intruder or hacker a fixed target to focus upon in that the end points of the VPN do not change, nor do the encryption methods and keys. The instant invention addresses the security concerns inherent in this system.

[0008] The instant invention is an apparatus and method for pre-negotiation and partial random generation of a secondary configuration of a VPN or other tunneled network for use in case the security of a main VPN is compromised. Configuration features such as the source and destination addresses of the nodes, their encryption keys, and their encryption algorithms are typically exchanged in order to establish a main VPN or tunneled network. In the instant invention, a set of usable addresses, usable encryption methods, along with randomly-generated keys are exchanged between the nodes in anticipation of a compromise of the main VPN or tunneled network. The tunneled nodes are configured to take advantage of one of the possible secondary VPN networks represented by these secondary configurations, should a compromise or attempted compromise be detected on the main VPN.

[0009] A compromise of the VPN or tunneled network may be detected through any one of several means known in the art, such as an alert from the server. In the instant invention, the secondary configurations exchanged between the nodes can be used to automatically establish a second VPN or tunneled network as the use of the main VPN or tunneled network is abandoned or fed with false data.

[0010] The foregoing outlines broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.

[0011] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0012] FIG. 1 is a system block diagram of a VPN network system;

[0013] FIG. 2 is a block diagram of a packet within a VPN or tunneled network protocol;

[0014] FIG. 3 is a block diagram of a computer used within a VPN network system;

[0015] FIG. 4 is a diagram depicting the relationship of IP addresses, encryption keys, and encryption methods within a VPN network system;

[0016] FIG. 5 is a diagram depicting the relationship of IP addresses, encryption keys, and encryption methods within a VPN network system, demonstrating a change made to the VPN network system by the instant invention;

[0017] FIG. 6A is a diagram illustrating the rotation of use of a set of available IP addresses by the instant invention;

[0018] FIG. 6B is a diagram illustrating the rotation of use of a set of available encryption keys by the instant invention;

[0019] FIG. 6C is a diagram illustrating the rotation of use of a set of available encryption algorithms by the instant invention;

[0020] FIG. 7 is a system block diagram of a VPN network system with one of the nodes having a main and a secondary VPN tunnel in operation; and

[0021] FIG. 8 is a flowchart diagram conforming to ANSI/ISO standard 5807-1985 describing the method of the present invention.

[0022] In the following description, numerous specific details are set forth such as protocol of network transmission, byte lengths, addresses, etc., to provide a thorough understanding of the invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. In other instances, well-known circuits, computer equipment, or network facilities have been shown in block diagram form in order to not obscure the present invention in unnecessary detail. For the most part, details concerning timing considerations, specific equipment and programming languages used, encryption methods used, and the like have been omitted in as much as these details are not necessary to obtain a complete understanding of the present invention and are within the skills of persons of ordinary skill in the art.

[0023] Within the context of this description, the term “node” is intended to encompass a processing machine, such as a computer, or group of processing machines or computers, such as a local area network (LAN) or wide area network (WAN), which are electrically attached to a network system. Therefore, a “node”, as used in this context, may encompass a single computer, a LAN of computers with a gateway, or a WAN of LANs with several gateways and routers. It is intended that the processing features described and attributed to a node could therefore be accomplished by a single computer, one or more computers, gateways or routers within a LAN, or one or more computers, gateways or routers within a WAN.

[0024] Within the context of this patent, the term “VPN” is intended to mean a virtual private network or any other encapsulated or tunneled networking protocol.

[0025] FIG. 1 depicts a VPN network system 108. An intranet 110 is a system of networked computers within an organization using one or more network protocols among them for communication. A intranet 110 may be comprised of one or more local area networks (LAN), wide area networks (WAN), or a combination of the two. Oftentimes, an associate intranet 112 will need to be connected to the intranet 110. An associated intranet 112 may be a business partner, supplier, or branch office. The associate intranet 112 may also be comprised of LANs, WANS, or a combination of the two. An individual may also need to access the intranet 110 remotely, through a remote access machine 114.

[0026] In a situation where the associate intranet 112 or the remote access machine 114 are not directly connected to the intranet 110, a system may be configured using the Internet 116 to connect the intranet 110 to the associate intranet 112 and the remote access machine 114. In such a situation, the intranet 110, the associate intranet 112, and the remote access machine 114 all become nodes on the Internet 116.

[0027] It is well-appreciated within the art that the Internet 116 is comprised of a series of machines networked using a TCP/IP network protocol. While the TCP/IP network presents a universal protocol which permits a wide variety of machines to connect to the Internet 116, it raises a great many security issues. Transmissions over the Internet 116 are not secure and are subject to eavesdropping, denial-of-service (DOS) attacks, snooping, and a variety of other security breaches. Accordingly, it is widely recognized as unsafe to transmit very sensitive data over the Internet 116 without some precaution in the form of encryption. Security concerns are increased whenever consistent and systematic communications are made over the Internet 116, such as those that would be required to maintain a network connection between the intranet 110 and associate intranet 112 or remote access machine 114.

[0028] Those skilled in the art will recognize virtual private networking (VPN) as a partial solution to these problems which currently exist in the art. A VPN tunnel 118 can be defined between the intranet 110 and the associate intranet 112 or the remote access machine 114. Each of the intranet 110, the associate intranet 112, and the remote access machine 114 then become nodes to the VPN tunnel as well as the Internet 116. The VPN tunnel 118 provides an encrypted facility through the Internet 116, through which data may pass between the intranet 110 and the associate intranet 112 or remote access machine 114.

[0029] An encapsulated packet for transmission through the VPN tunnel 118 is illustrated in FIG. 2 and an intranet packet 212 will consist of an IP Header 214 and a payload 216. The IP Header 214 is characteristic of a TCP/IP protocol, but those skilled in the art will recognize that such an encapsulation technique is frequently applied to other networking protocols within the art. The IP Header 214 contains such information as the address of the source machine, the address of the destination machine, and other administrative data. The payload 216, on the other hand, contains the data to be transmitted from the source machine to the destination machine. In a VPN network system, the original packet 212 is preceded by a new IP Header 218. The new IP Header 218 contains the same type of administrative information contained in the IP Header 214, however, the administrative information in the new IP Header 218 is such to communicate the entire packet to the end point of the VPN tunnel 118. Frequently the entire encapsulated packet 212 is encrypted before the new IP Header 218 is attached. In this way, a party who intercepts the tunneled packet cannot easily obtain any of the information from the original packet 212.

[0030] A representative hardware environment for practicing the present invention is depicted in FIG. 3, which illustrates a typical hardware configuration of a data processing system 313 in accordance with the subject invention having a central processing unit (CPU) 310, such as a conventional microprocessor and a number of other units interconnected via a system bus 312. System 313 includes memory 314, consisting of random access memory (RAM) and read only memory (ROM). System 313 also includes an input/output (I/O) adapter 318 for connecting peripheral devices such as disk units 320 to the bus 312, a user interface 322 for connecting a keyboard, mouse, and/or other user interface devices (not shown) to the bus 312, a communication adapter 334 for connecting the system 313 to a data processing network, such as a LAN and/or a WAN. The system 313 may also include a displayed unit 336 for connecting a displayed device (not shown) to the bus 312. CPU 310 may include other circuitry not shown herein, which will include circuitry commonly found within a microprocessor. System 315 can be used at each of the nodes discussed previously.

[0031] The communications adapter 334 is adapted to receive data from the bus 312 and conform that data to a network protocol for transmission over the network 340. Such a protocol may be TCP/IP, NetBIOS, or a variety of other networking protocols which are common within the art. The communications adapter 334 has one or more addresses associated with it, which it can use to ‘sign’ outgoing packets or which it can use to determine if an incoming packet is intended for it. The communications adapter 334 may use ‘aliasing’ to simultaneously associate more than one address with that communications adapter 334. The data to be transmitted becomes the payload 216 previously discussed in reference to FIG. 2. The communications adapter 334 may also be adapted to receive data from the network 340 and repackage or route that data as the payload 216 of an encapsulated packet.

[0032] The operation of the present invention is demonstrated in FIG. 4. An intranet structure 410 may have several VPN tunnel connections 412, 414. Each VPN tunnel connection 412, 414, has associated with it an IP address 430, an encryption key 432, and an encryption method 434. As is well-appreciated in the art, the IP address 430 is a unique address within the Internet 116 depicted in FIG. 1.

[0033] The encryption key 432 and the encryption method 434 can be any number of keys or methods as defined in the computer encryption art. A variety of encryption methods are available utilizing a variety of different size encryption keys 432, such that each machine has its own encryption key 432. Keys of 128-bits are common. The encryption key 432, when applied using the encryption method 434, permits the intranet structure 410 to encrypt and decrypt packets sent and received. It will be appreciated that the instant invention operates independently of the encryption keys 432 and the encryption methods 434 so that any encryption method with any number of keys may be used with the instant invention.

[0034] FIG. 4 also depicts associate intranet structures 432, each of which have an associated IP address, encryption key, and encryption method defining VPN tunnel connections 420. Likewise, a remote access structure 430 also has associated with it a remote VPN tunnel connection 418 having the same configuration information. The associate VPN tunnel connections 420 and the VPN tunnel connections 414 define a VPN tunnel 428. Likewise, the remote VPN tunnel connection 418 and the VPN tunnel connection 412 define a VPN tunnel 428.

[0035] The instant invention involves the exchange of the elements of a secondary VPN configuration, such as the IP address, encryption key, and encryption method, between an intranet structure 410 and a remote access machine 418 or associate intranet 420 immediately after a VPN tunnel 428, 426 has been established.

[0036] As addresses typically are required to be unique, the machines exchange at least one secondary address, but optimally a set of several addresses, which are or may be assigned to that machine. Likewise, the set of encryption methods supported by each machine is a fixed set, so that set of encryption methods supported is exchanged. Finally, a randomly-generated key for each encryption method is exchanged.

[0037] Once exchanged, the secondary configuration elements for the remote access machine 418 are stored by the intranet structure 410. Likewise, the intranet structure's 410 secondary configuration elements are stored on the remote access machine 418.

[0038] In the event that either the intranet structure 410 or the remote access machine 418 detects snooping or other possible security breaches along the VPN tunnel 428, the detecting machine will send a predetermined administrative change code to the other machine. The change code will designate which of the previously-exchanged secondary configuration elements are to be used. As the security of the VPN tunnel 428 may already be compromised, the change code must not include the actual secondary configuration elements. Rather, the change code should designate a code symbolizing which secondary configuration elements are to be used.

[0039] A embodiment of the method of the present invention is illustrated with reference to FIG. 8. A change algorithm 810 begins in step 812 with the precondition of a network system. A primary VPN tunnel is established in step 814 between two nodes of the network system. Then, in step 816, the nodes exchange secondary VPN configuration information. Such exchange can occur over the primary VPN tunnel previously established in step 814. The algorithm 810 then waits until a compromise is detected in step 818. As previously noted, a compromise may be a security breach or a technical failure. Upon compromise, the detecting node sends the administrative change code to the remote node in step 820. Thereupon, both the detecting and remote nodes automatically negotiate a secondary VPN tunnel in step 822.

[0040] Following establishment of the secondary VPN tunnel in step 822, the algorithm 810 may provide for either abandonment of the primary VPN tunnel in step 824 or for that primary VPN tunnel to be fed with false data in step 826. The algorithm may then be terminated in step 828, as shown, or, in an alternative embodiment, may loop to exchange additional VPN information in step 816.

[0041] FIG. 5 represents a possible result of an administrative change code. The intranet structure 510 has reconfigured the end of a secondary VPN tunnel 528 in accordance with the secondary configuration information 512. Likewise, the remote access machine 518 has reconfigured using the VPN configuration information previously sent to it by the intranet structure 510. As a result, the secondary VPN tunnel 528 now exists between two different IP addresses, utilizes different encryption keys, and utilizes a different encryption method. Any attempts to compromise the security of the original VPN tunnel 428 is stymied.

[0042] FIG. 7 illustrates the layout of the VPN network system 708 after the secondary VPN tunnel 720 begins to operate. The original VPN tunnel 718 will still be active at this point in time. Due to its compromise, however, the original VPN tunnel 718 should not be used to communicate between the intranet 710 and the remote access machine 714.

[0043] Upon establishing the secondary VPN tunnel 720, the original VPN tunnel 718 may be abandoned or fed with false data. It will also be appreciated that a single VPN tunnel may be changed without modifying other VPN tunnels within the same system 708.

[0044] The secondary configuration elements selected by the machine sending a change code may be selected by any number of algorithms, and it will be appreciated that many variations on the procedures outlined herein are possible and evident given this disclosure. In fact, the nearly infinite variety of different selection algorithms will enhance security.

[0045] One possible algorithm for selection of addresses is demonstrated by FIG. 6A. A main VPN address 610 is ordered with a first secondary address 612, some number of additional secondary addresses 616, and a final secondary address 614. The main VPN address 610 has associated therewith a main VPN address code 620. Likewise, the first secondary address 612, the number of additional secondary addresses 616, and the final secondary address 614 also have associated therewith secondary address codes 622, 626, 624. Upon detection of a compromise, the detecting machine may simply send change code to change to the next address in order. For example, the first compromise will result in the address being changed from the main VPN address 610 to the first secondary address 612. The second compromise would cause the address to likewise shift down the ordered list of addresses until the final secondary address 614 is reached, at which time the next address selected would be the main VPN address 610 again.

[0046] In an alternate embodiment, the detecting machine may send a change code which specifies the main or secondary address code 620, 622, 626, 624 corresponding to the address to which to change. The address code specified may be determined randomly from the set of available address codes. As both nodes have the same associations of address codes to IP addresses, an identical change is made to the corresponding IP address 610, 612, 616, 614 at each node.

[0047] It will be appreciated that these same types of algorithms may be used to select from a set of useable encryption keys or encryption algorithms, as indicated in FIG. 6B and FIG. 6C, respectively. It should also be noted that alternatively encryption keys may be randomly generated and non-repeating, so that each time a key is used, a new key is generated to replace it. New keys may be exchanged immediately upon creation, when security of the VPN tunnel is assured.

[0048] Not all configuration aspects of the changing VPN tunnel 528 need change. For example, in an alternative embodiment, the addresses may be changed, leaving the encryption keys and methods the same. However, maximum security benefit will be achieved if all configuration data for the VPN tunnel 528 changes.

[0049] As to the manner of operation and use of the present invention, the same is made apparent from the foregoing discussion. With respect to the above description, it is to be realized that although embodiments of specific material are disclosed, those enabling embodiments are illustrative and the optimum relationships for the parts of the invention are to include variations in composition, form, function and manner of operation, which are deemed readily apparent to one skilled in the art in view of this disclosure. All equivalent relationships to those illustrated in the drawings encompassed in this specification are intended to be encompassed by the present invention.

[0050] Therefore, the foregoing is considered as illustrative of the principals of the invention and since numerous modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown or described, and all suitable modifications and equivalants may be resorted to, falling within the scope of the invention.