Patent Application
20240289434
The present invention relates to computing systems and, more particularly although not exclusively, to apparatus and methodologies for operation of memory structures within the computing systems. Particularly although not exclusively the present invention relates to structuring memory and code within memory so as to minimise the opportunity for malware to execute.
The problem of attack from malicious software is well known in the art. Typically an attacker gains control of a target computer and then loads malicious software on that computer to be run in order to perform malicious tasks. For example Ransomware is a type of malware that is loaded onto a target computer and starts encrypting the contents of the computer's storage with the aim of ransoming the owner to obtain a decryption key to undo the encryption.
A current way of stopping this from happening is to monitor the computer for any encryption activity and to try and stop the offending process before significant encryption or damage is done.
There are many types of malware including Trojans worms and unauthorised remote control software. Anti virus software typically looks for the presence of known or questionable executable applications and disabling or deleting them before they cause a problem.
Most of these problems would be addressed for many computing applications if executable applications were stored in and limited to read only storage space and any data storage or retention required by each application was restricted to data only writeable memory space where no executable applications could be launched. This configuration of computing storage would stop malicious applications from being loaded onto the computer and being executed. This capability however is not offered by today's computing platforms.
Stated another way, malware has been and continues to be a major issue in the computing world. It is particularly a problem where a user is tricked into downloading malware—often without realising that a download has been triggered. Whilst many attempts have been made to educate users to be alert to situations where they may inadvertently cause the downloading of malware to their computer, those who generate malware continue to remain one step ahead.
Broadly, therefore, the computing community really needs to structure computer hardware and firmware such that any malware that is downloaded simply will not execute.
GB2230881A discloses hardware for implementing different access security levels in a computer system. The methodology is based on controlling dataflow to memory rather than controlling the inherent behavioural capability of the memory.
US2014/0229743A1 seeks to create a malware resistant architecture by providing a mechanism for separating a dataflow comprising comingled instructions and data so as to direct to the instructions to an instruction memory and the data to a data memory. The methodology for making the memory structures malware resistant comprises applying encryption to the instructions/data in the memory structures.
Embodiments of the described invention seek to address these issues.
It is an object of the present invention to address or at least ameliorate some of the above disadvantages.
The term “comprising” (and grammatical variations thereof) is used in this specification in the inclusive sense of “having” or “including”, and not in the exclusive sense of “consisting only of”.
The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.
Binary Loader: A binary loader is a part of the operating system of a computing platform that loads and executes binary files from storage into memory. It is in the form of executable code which reads the executable file, prepares it for execution by setting up the necessary memory space, and then transfers control to the loaded program to begin execution.
Malware: In this specification, malware refers to malicious software code which is to say blocks of code that, if executed on a computing platform, will cause behaviour of the computing platform not instructed or expected by the operator of the computing platform.
In one broad form, a solution to one or more of the problems outlined above may be found in structuring computer hardware and firmware on a computing platform so as to test certain aspects of a block of code and the environment in which it is located prior to a binary loader of a computing platform loading and executing the block of code.
In instances where the block of code fails one or more of the tests then the block of code is not loaded and/or is not executed by the binary loader.
Accordingly, in a further broad form of the invention there is provided a computer system comprising a processor in communication with a memory structure; the processor retrieving and executing executable code stored in the memory structure thereby to process data stored in and retrieved from the memory structure; the memory structure including at least an area designated as an executable application code storage area and a separate area designated as a data storage area.
Preferably the system structures computer hardware and firmware on a computing platform of the computer system so as to test certain aspects of a block of code and the environment in which it is located prior to a binary loader of the computing platform loading and executing the block of code.
Preferably in instances where the block of code fails one or more of the tests then the block of code is not loaded and/or is not executed by the binary loader.
In yet a further broad form of the invention there is provided a method of operating a computer system; the computer system comprising a processor in communication with a memory structure; the processor retrieving and executing executable code stored in the memory structure thereby to process data stored in and retrieved from the memory structure; the memory structure including at least an area designated as an executable application code storage area and a separate area designated as a data storage area; the method comprising
Preferably in instances where the block of code fails one or more of the tests then the block of code is not loaded and/or is not executed by the binary loader.
Accordingly in a further broad form of the invention there is provided a computer system comprising a processor in communication with a memory structure; the processor retrieving and executing executable code stored in the memory structure thereby to process data stored in and retrieved from the memory structure; the memory structure including at least an area designated as an executable application code storage area and a separate area designated as a data storage area.
Preferably the executable application code storage area is switchable by a memory state switch structure between at least a first state and a second state;
Preferably the executable application code is not permitted to be stored in the data storage area.
Preferably the executable application code is not permitted to be executed from the data storage area.
Preferably the executable application code storage area and the separate data storage area are located within the same memory structure.
Preferably the processor is a single processor.
Preferably the processor comprises at least a first processor and a second processor.
Preferably the computer system comprises multiple processors; each processor adapted to execute code adapted for predefined, separate tasks.
Preferably the processor performs the function of the memory state switch structure.
Preferably the executable application code is stored in a predetermined directory structure and the processor sets the read write status of the predetermined directory structure to read and write status during loading of the executable application code and then sets the read write status of the predetermined directory structure to read only status in order to permit execution of the executable application code by the one or more processors.
Preferably the memory status switch structure comprises a manually operable switch.
Preferably the memory state switch structure is located locally to the computer system.
Preferably the memory status switch structure is located remote from the computer system.
Preferably the processor executes a hash of the executable application code stored in the executable application code storage area and compares the hash with a previously stored hash value thereby to determine if the executable application code has been changed.
Preferably the processor executes the hash every time the executable application code is stored in the executable application code storage area.
Preferably the processor executes the hash at predetermined time intervals.
Preferably preparatory to use of the memory structure whilst the memory structure is in its second state a memory state test is conducted to confirm the memory is in a read only state.
In a further broad form of the invention there is provided a method of minimising introduction of malware into a computer system; the method comprising providing a memory structure for storage of executable code by a processor of the computer system; the memory structure switchable between a first state which permits the processor to write to and read from the memory structure and a second state which permits the processor to read from the memory structure but not write to the memory structure.
Preferably the executable application code is not permitted to be stored in the data storage area.
Preferably the function of changing the state of the memory is performed by the operating system kernel.
Preferably preparatory to use of the memory structure whilst the memory structure is in its second state a memory state test is conducted to confirm the memory is in a read only state.
Preferably a digital input/output device incorporating means to implement the method as described above.
Preferably the device implemented as a software application on a smart phone.
Preferably a medium storing code thereon which, when executed by a processor, effects the method as described above.
Preferably the medium of is a non-transitory medium.
Preferably a digital input/output device incorporating means to recognize a physiological feature preparatory to executing the executable in accordance with the method as described above.
Preferably the device implemented as a software application on a smart phone.
Preferably a digital input/output device incorporating means to implement the computer system as described above.
Preferably the device implemented as a software application on a smart phone.
Preferably a medium storing code thereon which, when executed by a processor, effects the computer system as described above.
Preferably the medium is a non-transitory medium.
Preferably a digital input/output device incorporating means to recognize a physiological feature preparatory to executing the executable in accordance with the computer system as described above.
Preferably the device implemented as a software application on a smart phone.
Preferably the computer system hardware is constituted as a Harvard architecture computer system.
Preferably the computer system hardware is constituted as a modified Harvard architecture computer system.
In a further broad form of the present invention there is provided in a computer system; the computer system hardware comprising a Harvard architecture computer system; a method of minimising introduction of malware into the computer system; the method comprising providing a memory structure for storage of executable code by a processor of the computer system; the memory structure switchable between a first state which permits the processor to write to and read from the memory structure and a second state which permits the processor to read from the memory structure but not write to the memory structure.
Preferably executable application code is not permitted to be stored in the data storage area.
Preferably the function of changing the state of the memory is performed by the operating system kernel.
Preferably preparatory to use of the memory structure whilst the memory structure is in its second state a memory state test is conducted to confirm the memory is in a read only state.
In a further broad form of the present invention there is provided in a computer system; the computer system hardware comprising a modified Harvard architecture computer system; a method of minimising introduction of malware into the computer system; the method comprising providing a memory structure for storage of executable code by a processor of the computer system; the memory structure switchable between a first state which permits the processor to write to and read from the memory structure and a second state which permits the processor to read from the memory structure but not write to the memory structure.
Preferably executable application code is not permitted to be stored in the data storage area.
Preferably the function of changing the state of the memory is performed by the operating system kernel.
Preferably preparatory to use of the memory structure whilst the memory structure is in its second state a memory state test is conducted to confirm the memory is in a read only state.
In a further broad form of the invention there is provided a computer system comprising a processor in communication with a memory structure;
Preferably the processor is a single processor.
Preferably the processor comprises at least a first processor and a second processor.
Preferably the computer system comprises multiple processors; each processor adapted to execute code adapted for predefined, separate tasks.
Preferably one of the processors performs the function of the memory state switch structure.
Preferably the memory status switch structure comprises a manually operable switch.
Preferably the memory state switch structure is located locally to the computer system.
Preferably the memory status switch structure is located remote from the computer system.
In a further broad form of the invention there is provided a method of minimising introduction of malware into a computer system; the method comprising providing a memory structure for storage of executable code by a processor of the computer system; the memory structure switchable between a first state which permits the processor to write to and read from the memory structure and a second state which permits the processor to read from the memory structure but not write to the memory structure.
Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:
In one broad form, a solution to one or more of the problems outlined above may be found in structuring computer hardware and firmware on a computing platform so as to test certain aspects of a block of code and the environment in which it is located prior to a binary loader of a computing platform loading and executing the block of code.
In instances where the block of code fails one or more of the tests then the block of code is not loaded and/or is not executed by the binary loader.
In a typical storage system an area of the storage 11 is set aside for applications 1213 relating to the computers operating system, while in other parts of the storage 14 non operating system applications 1516 are stored in readiness for execution by the computer to perform different tasks.
In each case the applications 12131516 may use read and writeable storage to store data 17181920 related to the applications 12131516 in order for the application to operate. For example logging data, state updates, user data and communications could be used by the great majority of applications.
A problem exists where the necessity of an application to access readable and writeable storage leaves an opportunity for an attacker to use the writeable storage space to load and run malicious software since all of the storage 10 can be used for application execution and writing of data.
An executable application storage area 41 is only write enabled during initial application 4344 and initial operating system 4546 loading. Subsequently the executable application storage area 41 is write disabled so that no new applications can be added to storage in order to be executed.
These operating system applications 4546 and other applications 4344 must access related data files 47484950 and data storage capabilities that are in a data only storage area 42. This data only storage area 42 allows data to be written and read, but does not allow application data to be written, accessed or executed.
If an attacker obtains access to the computer, a storage system with this capability will not allow executable applications to be stored to the data storage area or executed since the operating system has been modified to allow execution of applications only from storage space that is not writeable.
An additional security feature of the example embodiment could be a hash 51 of the application execution storage area 41 that is verified before any application is allowed to run. This hash 51 can be used to verify that the non writeable application storage area 41 has not been modified or altered thereby verifying the integrity of the applications stored at that location.
In the example embodiment a physical switch is used to switch the application execution storage space between writeable and non writeable or locked states. This means that a person must be physically at the computer to engage the storage writeable switch to allow the application execution storage area to be updated or modified.
With reference to
In this instance, the computing system 200 comprises a processor 201 in communication with a bus 202 which is in communication with a first memory structure 203 and also in separate communication with a second memory structure 204.
In this instance, the first memory structure 203 is switchable between a first state and a second state by operation of a memory state switch apparatus 205.
In a first state the memory state switch apparatus 205 permits the first memory structure 203 to be written to and read by processor 201 via bus 202. In a second state the memory state switch apparatus 205 permits the first memory structure to be read by a processor 201 but not written to by processor 201.
The memory state switch apparatus 205 may be implemented as a single pole switch operating a memory bus 206 whereby in its open position memory bus 206 is in a first voltage state—for example 0 volts corresponding to the first state which permits the first memory structure 203 to be written to and read by processor 201 via bus 202. In second closed state the single pole switch applies a second voltage state to the memory bus 206—for example +5 volts which permits the first memory structure to be read by a processor 201 but not written to by processor 201.
With reference to
Once fully loaded and with reference to
By way of further example and with reference to
Once fully loaded and with reference to
In
In a further preferred form, a similar check step capability can be arranged for the data storage whereby a hash 211A of data 212A is made at the time the data is first loaded into data storage 204. The check step can be performed by processor 201 prior to retrieval and use of the data 212A by the processor 201 performing a hash of data 212A and comparing the hash value thus derived with hash 211A.
In a further form once the system is in the state of
A similar memory state check for memory 204 can be undertaken preparatory to use of data stored in memory 204. The intention is to provide an additional check that the memory status, for whatever reason, has not been changed to a writable state thereby placing the code or data stored therein at risk.
Stated in another way for this embodiment preparatory to use of the memory structure whilst the memory structure is in its second state a memory state test is conducted to confirm the memory is in a read only state. The test may simply comprise the CPU transferring a block of data via the programme memory bus to the programme memory and determining whether the block of data can be read subsequent to the transfer.
For clarity elsewhere in this patent the term kernel is used to describe the binary loader. In specific technical terms the binary loader is the application at the core of the operating system that is responsible for placing executable code into volatile memory from non volatile memory and running. In less specific use cases the term kernel may include other core components besides the binary loader or compiled executable code. However in order to maintain maximum integrity of the ability for the operating system to resist tampering, the binary loader modified in accordance with embodiments of the present invention itself must handle the techniques described in the example embodiment to minimise the opportunity for hackers to install and run rogue executables (malware).
Initially the computer typically runs a BIOS when switched on. The BIOS then typically uses a function called a boot loader to find the operating system 102 stored in the computer's non-volatile memory 101.
Within the operating system 102 there is a binary loader 103 which is responsible for copying executables from non-volatile memory 101 into volatile memory 100 and running them.
On the initial loading of the operating system 102, the binary loader 103 is loaded 114 from non-volatile memory 101 into volatile memory 100 and run 104.
It is also important to note that the operating system in this example embodiment has been pre-configured to ensure all operating system components 102 and installed applications 106 in non-volatile memory 106 are all in directories 102106 that are set and flagged to be read only 107118 and thus not writable.
In the example embodiment the modified loader 103104 not only loads and runs executable binaries but does a number of checks before running the requested executable.
These checks include checking that the location of the executable 105 is stored in a directory 106 that is flagged for storage of legitimately installed applications. It also checks that the directory 106 is not writable 107 and read only. It may do this by attempting a test write to the non volatile memory to be assured that the state of the memory is indeed read only.
Note that the installation of legitimate applications 105 may involve a separate boot process using separate installation software.
During the same process the modified binary loader 104 runs a hash verification of the application space of the application to be run and compares it to the stored hash 108 of the application space106 completed at installation to ensure there has been no modification of either the executable 105 or its related files before running.
The modified loader 104 can also be enabled to do a hash check of the operating system storage area itself 102 and then compare the results with a stored hash 109 that was calculated at installation
If one or any of the above conditions fail then the modified loader 104 notifies the user of failure and terminates the load of the requested executable into volatile memory 100. If all conditions of the various checks are successful, then the binary loader 104 finds 115 the executable 105 in its location in non-volatile memory 101 and copies 116 the executable into volatile memory 100 and runs it 119.
Using the above process, the rest 110 of the computer's non-volatile memory 101 could be used for data files 111 and user space.
A typical form of malware attack involves tricking the user or surreptitiously downloading a rogue executable 112 into the computer user space 110 and either trying to install it or run it.
Upon request to the modified loader 104 to run 117 a rogue executable 112, the modified loader 104 checks to see if the requested executable 112 is in installed application directories 106 or the operating system directory 102 and whether the location of the executable is write enabled 113 or not. If either of these tests fails or if the hash for the operating system 109 or application space 108 has shown to be tampered with or modified then the load request is terminated and the user informed.
When first run typically a computer will use a BIOS 140 bootstrap operation 143 which is stored and run from firmware 140 to find 144 the operating system stored in non-volatile memory 141 and more specifically the modified binary loader as described in the example embodiment in the operating system 145 and then placing it 146 into volatile memory 142 and running it 146.
The example embodiment also includes a series of changes to a normal operating system which are already in place at the time the operating system is first run by the BIOS. These include the modified binary loader, the setting of key directories as flagged to be non writable and at least one stored hash calculation figure stored as a file for each directory in which authorised executables are stored in non-volatile memory.
Subsequently the modified binary loader waits for an executable to be run 147. When a request for an executable to run is made 148 the modified binary loader runs through a series of checks before allowing the executable to run. The diagram shows a specific order of checks but an alternative embodiment could run the checks in any order or include or exclude checks as the circumstances require.
In this example embodiment the modified binary loader runs a directory check 149 of the executable that has been requested to load. The check ensures that the requested executable is in a directory set aside for storage in non-volatile memory 141 that is designated for the storage of an installed application 150, or a directory set aside for the installed operating system in use 150. If the executable is not in a recognised directory then the load request is terminated 151 and the user is informed 151.
For example in the Apple MacOS operating system all applications are stored in subdirectories of the folder named “Applications”. And all operating system applications are stored in subdirectories to the folder named “System”.
If the directory is authorised, then the directory in question is checked to have its writable state flagged as writable 152. If the directory is write enabled, which it should not be, then the execution request 148 is terminated 151 and the user informed 151. If a properly installed application or operating system directory is not read only, it means that the directory or the operating system have been tampered with and that execution of the requested executable should be questioned.
If the directory in question is not write enabled 153 then the modified binary loader can do a test write of some data to the target directory 154 to determine if indeed the directory is in a read only state. The reason that writing of test data is only after checking the directory location 149 and directory write state 152 is so that easier and faster checks are done before writing data to the directory which may slow down the loading process.
After the writing data test 154 if the data proves to be writable the executable run request 148 is terminated 151 and the user notified 151. If the attempt to write test data fails 155 then the process moves onto the next check which involves doing a hash of the directory in which the target executable is stored 156 in non-volatile memory.
After the hash is generated 156, a stored copy of the target directory hash is retrieved 157 from non-volatile memory 141. The stored hash value for the target directory was calculated and written to non-volatile memory during an installation process at a previous time 158 and is not covered in this patent.
If the two hashes do not match then the request to run an executable 148 is terminated 160 and the user notified 160. If the hashes do match, then the target executable 148 is copied 161 from non-volatile memory 141 into volatile memory 162 and run 162.
The example embodiment uses a physical switch to write enable and write disable the application execution area of the computer's storage. Such a capability may be advantageous in a device such as a modem or a router where the upgrades to the operating system are relatively rare and simple. An alternative embodiment could use a remote mode switch control that may or may not use the hash to verify any modification or tampering with the application storage space. Another embodiment could use firmware and related boot startup code that is not part of the storage system to switch between enabling the application storage space for read only or write enabled.
The example embodiment anticipates a computer storage system that is set to write enabled and write disable using operating system or control software. For example a hard drive that is writeable could be allocated some space that is made virtually un-writable by the operating system thereby stopping an attacker from installing and running applications.
Typically such a capability would involves a customised operating system kernel that would not allow applications to run if the application is running from storage space that is writeable.
In another alternative embodiment a cloud based computer system could be set to allow applications to be executable from only a specific directory on a storage system and where that directory is marked as non writeable by the operating system and then the contained applications are given access to data storage areas that are outside the write disabled directory. However areas outside the write disabled directory cannot be used for launching or initiating applications.
The example embodiment anticipates a hash calculation of the whole application and operating directory space to ensure there has been no unauthorised modification or addition to the device. An alternative embodiment could include a hierarchy or library of hashes to allow individual applications or groups of applications to be added to or removed from the device securely for use in read only memory mode.
The example embodiment anticipates an upgrade capability that only allows the application or operating system storage space to be written to when the device is in an upgrade mode and where only an upgrade application is allowed to run. The upgrade process though not described in this patent would no doubt include an install image checking capability to ensure the applications or executables to be installed are verified and not tampered with before installation which may involve restarting the device in memory writeable mode but only allowing an upgrade application to run after verifying the install image for integrity. The device would then be restarted in operating system and application memory read only mode for normal operation.
The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.
Embodiments disclose a method of operation of a computing platform whereby the opportunity for malicious code to execute on the platform is minimised if not entirely eliminated. Particular examples of a computer platform include a server or a personal computer.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017903155 | Aug 2017 | AU | national |
| 2017903180 | Aug 2017 | AU | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16636914 | Feb 2020 | US |
| Child | 18605893 | US |
