# Patent

## Title
System and method for the managed security control of processes on a computer system

## Abstract

Managing and controlling the execution of software programs with a computing device to protect the computing device from malicious activities. A protector system implements a two-step process to ensure that software programs do not perform malicious activities which may damage the computing device or other computing resources to which the device is coupled. In the first phase, the protector system determines whether a software program has been previously approved and validates that the software program has not been altered. If the software program is validated during the first phase, this will minimize or eliminate security monitoring operations while the software program is executing during the second phase. If the software program cannot be validated, the protector system enters the second phase and detects and observes executing activities at the kernel level of the operating system so that suspicious actions can be anticipated and addressed before they are able to do harm to the computing device.

## Background
PRIORITY AND RELATED APPLICATIONS
The present application is a continuation of and claims priority to pending U.S. patent application Ser. No. 10/336,299, filed Jan. 3, 2003, which claims priority to and incorporates herein provisional patent application entitled, “System and Method for the Managed Security Control of Processes on a Computer System,” filed on Jan. 4, 2002 and assigned U.S. application Ser. No. 60/345,432.


TECHNICAL FIELD
The present invention is generally directed to managing the security of a network. More specifically, the present invention provides kernel-level protection of a computer system from rogue or malicious computer programs.
BACKGROUND OF THE INVENTION
The security of computing networks is an increasingly important issue. With the growth of wide area networks (WANs), such as the Internet and the World Wide Web, people rely on computing networks to locate, transfer, and store an increasing amount of valuable information. This is also true of local area networks (LANs) used by companies, schools, organizations, and other enterprises. LANs generally are used by a bounded group of people in an organization to communicate and store electronic documents and information. LANs typically are coupled to or provide access to other local or wide area networks. Greater use and availability of computing networks produces a corresponding increase in the size and complexity of computing networks.
With the growth of networks and the importance of information available on the networks, there is also a need for better and more intelligent security. One approach to securing larger and more complex computer networks is to use a greater number and variety of security assessment and intrusion detection devices. Security assessment devices can be used to evaluate elements in the network such as desktop computers, servers, and routers, and determine their respective vulnerability to attack from hackers. Intrusion detection devices, on the other hand, identify and prevent entry of foreign or malicious computer programs and can notify a network manager of the presence or attempted entry of such a computer program. Security assessment and intrusion detection devices can also be used more frequently to monitor the activity or status of the elements in a computing network.
However, simply adding devices or filters to a network is not always the only and best solution to maintaining network security. Adding security devices can complicate the network and inundate the network manager with security data. Threats to the security of a device or network can take a variety of forms including the introduction of harmful computer code, unauthorized attempts to gain access, and misuse by people with authority to use a device or network. The various types of harmful computer code that can threaten a computing device or distributed computing system can generally be categorized as either a virus or some form of “malware”. Computer viruses harm computing devices and systems by entering and then propagating. In some respects, the propagating nature of computer viruses makes them easier to detect and there are many commercially available products that detect and exclude viruses from computing devices and systems.
In contrast, malware is a general description for other types of programs and computer code that are designed to harm a computing device or system in ways other than simply propagating as a virus does. Malware presents a more sophisticated challenge for network security and traditional anti-virus software is not designed to prevent malware from harming computing devices and networks. Malware can take a variety of forms including corrupted applications and applications that retrieve corrupted code that is modified to harm a computing device or network.
There are generally two different approaches to protecting against malware. The first approach involves virtual execution of a computer code to attempt to identify harmful code before it is allowed to actually execute. Virtual execution is limited in its ability to detect harmful code because it does not actually execute every process of the code. Instead, the virtual execution technique performs a quick and high-level “walk through” of the processes in the code to attempt to detect suspicious patterns in the code. By its nature, the virtual execution technique is limited in its ability to detect suspicious activities embedded in a piece of code. As a result, when the virtual execution technique is implemented, it must be used conservatively which produces a high number of false positive alerts. In other words, because the virtual execution security technique is not as accurate as actually running the code, it is implemented to identify a broader scope of potentially suspicious code and produces a greater number of alerts to the user. A high percentage of false positive security alerts is undesirable because it translates into a greater number of security interruptions for the user.
The second approach involves controlling and monitoring a computing device in real time while it is actually running a program and attempting to anticipate any harmful activity the program may try to initiate. One example of a real-time solution is set forth in U.S. Pat. No. 5,987,611, which describes a client-based monitoring system for filtering network access in conjunction with a centralized enforcement supervisor. The supervisor maintains access rules for the client-based filtering and verifies the existence and proper operation of the client-based filter application. Access rules specify network access criteria for a client, such as (1) total time a user can be connected to the Internet (e.g., per day, week, month, or the like), (2) time a user can interactively use the Internet (e.g., per day, week, month, or the like), (3) a list of applications or application versions that a user can or cannot use in order to access the Internet, (4) a list of URLs (or WAN addresses) that a user application can (or cannot) access, (5) a list of protocols or protocol components that a user application can or cannot use, and (6) rules to determine what events should be logged (including how long are logs to be kept).
By intercepting process loading and unloading and keeping a list of currently-active processes, each client process can be checked for various characteristics, including checking executable names, version numbers, executable file checksums, version header details, configuration settings, and the like. With this information, a determination can be made whether a particular process in question should have access to the Internet and what kind of access (i.e., protocols, Internet addresses, time limitations, and the like) is permissible for the given specific user.
The limitation with the solution presented in U.S. Pat. No. 5,987,611 and other similar real-time prior art solutions is that they are packet based. In other words, the security decisions are based on the data packets that are passing between the computing device that is being monitored and external networks or computing resources. When security decisions are based on the traffic of data packets, it is more likely the security systems will not detect harmful activities until after the harm has already begun. Accordingly, the second approach is not satisfactory because conventional real-time security monitoring solutions do not detect security problems early enough and allow time for a response before the malicious program does harm.
In view of the foregoing, there is a need in the art for a security system which will provide early detection of security threats to a computing device or network before any harm can be done. Specifically, a need exists to be able to quickly and efficiently examine code in real time, but before it is able to harm a computing device or system. A further need exists for a computer security system that can accurately identify security threats contained in software programs so that users are not interrupted frequently to address potential security questions. Finally, a security system is needed that can efficiently and effectively respond to security threats detected in software programs.
SUMMARY OF THE INVENTION
The present invention satisfies the above-described needs by evaluating and monitoring software programs running on a computing device. The invention uses a protector system that comprises several different software modules for performing evaluation, detection, monitoring, and response functions. Implementing a two-phased approach at the kernel level of the computing device's operating system, the present invention provides fast and efficient security that minimizes interruptions for the user. The first phase, the pre-execution process, performs a rapid validation check to determine whether the program has been approved for the computing device or network. If the program is validated, it can be run without further monitoring or interruptions for the user. If the program is not validated, it can be monitored at the kernel level of the operating system during the second phase, while the program is executing. Detection and monitoring modules of the present invention can identify suspicious activities triggered by the program and monitor the activities before they are able to cause harm to the computing device or network. In the event the program is initiating harmful activities, the protector software module can respond by taking remedial action to address the threat.
In one aspect, the present invention comprises a method for determining whether a program is approved to execute by comparing it to a predetermined list of approved programs. The operating system kernel notifies a pre-execution monitoring module when a new program begins to load so that it can be validated before execution. A validation module can compare the new program to the predetermined list of approved programs. If the new program is validated, the pre-execution monitoring module allows the operating system to continue loading and executing the program. Once a program is validated in the pre-execution phase, little or no additional security monitoring needs to be performed on the new program while it is executing. If the new program is not validated, the program can continue to load and execute, but other execution security modules are responsible for detecting, monitoring, and responding to suspicious activities. For example, the execution security modules can control access to certain files or registry settings, or limit network access. The execution security modules can also consider whether a new program was previously permitted to execute on the computing device.
In another aspect, the present invention provides a protector system for improving and expediting security on a computing device or network. The protector system comprises several software modules coupled to the operating system kernel of the computing device that manage and control activities at the kernel level. The protector system comprises a pre-execution monitoring component that can suspend a new program as it is loading into memory and before it can execute. The pre-execution monitoring component can operate with a validation module to determine whether the user has already validated the new program. If the pre-execution component validates the new program, it can continue to load and execute with minimal security concerns. However, if the pre-execution component is unable to validate the new program, execution security modules can perform additional monitoring while the new program is executing. Execution security modules can intercept various operating system triggers and calls before they are executed to determine if the activity is suspicious. If the program's activities are deemed suspicious or malicious, the execution security modules can respond by terminating the activities or taking other responsive measures to protect the security of the computing device or network.



These and other aspects of the invention will be described below in connection with the drawing set and the appended specification and claim set.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating an exemplary architecture for operating an embodiment of the present invention.
FIG. 2 is a block diagram illustrating components of a database implemented in accordance with an exemplary embodiment of the present invention.
FIG. 3 is a logic flow diagram illustrating a setup process for implementing the protector system in accordance with an exemplary embodiment of the present invention.
FIGS. 4A and 4B are logic flow diagrams illustrating a pre-execution process using the protector system in accordance with an exemplary embodiment of the present invention. FIG. 5 is a logic flow diagram illustrating a validation process using the protector system in accordance with an exemplary embodiment of the present invention.
FIG. 6 is a logic flow diagram illustrating a non-validated execution process using the protector system in accordance with an exemplary embodiment of the present invention.
FIG. 7 is a logic flow diagram illustrating a file protection process using the protector system in accordance with an exemplary embodiment of the present invention.



DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
The present invention employs a protector system comprising several software modules to support the protection of computing devices and computing networks from malicious software programs. Specifically, the present invention employs a two-step process to validate software programs and monitor non-validated software programs. The two-step process provides an efficient and effective means for protecting a computing device or network while minimizing disruptions for the user. In the first phase of the process, the protector system validates authorized programs to ensure that they have not been corrupted before running them. For programs that cannot be validated, the protector system can monitor the programs as they execute during the second phase. If during the monitoring step, the program initiates any suspicious activities, the protector system can respond by taking one or more remedial actions.
Although the exemplary embodiments will be generally described in the context of software modules running in a distributed computing environment, those skilled in the art will recognize that the present invention also can be implemented in conjunction with other program modules for other types of computers. In a distributed computing environment, program modules may be physically located in different local and remote memory storage devices. Execution of the program modules may occur locally in a stand-alone manner or remotely in a client/server manner. Examples of such distributed computing environments include local area networks of an office, enterprise-wide computer networks, and the global Internet.
The detailed description that follows is represented largely in terms of processes and symbolic representations of operations in a distributed computing environment by conventional computer components, such as database servers, application servers, routers, security devices, firewalls, clients, workstations, memory storage devices, display devices and input devices. Each of these conventional distributed computing components is accessible via a communications network, such as a wide area network or local area network.
The processes and operations performed by the computer include the manipulation of signals by a client or server and the maintenance of these signals within data structures resident in one or more of the local or remote memory storage devices. Such data structures impose a physical organization upon the collection of data stored within a memory storage device and represent specific electrical or magnetic elements. These symbolic representations are the means used by those skilled in the art of computer programming and computer construction to most effectively convey teachings and discoveries to others skilled in the art.
The present invention also includes computer programs that embody the functions described herein and illustrated in the appended flow charts. However, it should be apparent that there could be many different ways of implementing the invention in computer programming, and the invention should not be construed as limited to any one set of computer program instructions. Further, a skilled programmer would be able to write such a computer program to implement the disclosed invention based on the flow charts and associated description in the application text, for example. Therefore, disclosure of a particular set of program code instructions is not considered necessary for an adequate understanding of how to make and use the invention. The inventive functionality of the claimed computer program will be explained in more detail in the following description in conjunction with figures illustrating the program flow.
Referring now to the drawings, in which like numerals represent like elements throughout the several figures, aspects of the present invention and the preferred operating environment will be described.
FIG. 1 illustrates various aspects of an exemplary computing environment in which an embodiment of the present invention is designed to operate. Those skilled in the art will appreciate that FIG. 1 and the associated discussion are intended to provide a representative description of the computer components in an exemplary protector system.
FIG. 1A illustrates aspects of an exemplary computing environment in which an embodiment of the invention is designed to operate. For example, exemplary computing device 194 can comprise software modules performing the processes described herein, wherein the software modules can be stored in exemplary computer-readable storage device 195 and be executed by exemplary processor 196 via exemplary random access memory 197. Computing device 194, computer-readable storage device 195, processor 196, and random access memory 197 are conventional computing components well known to those of ordinary skill in the art. Other embodiments of the invention may operate in other types of computing environments.
Referring to FIG. 1, an exemplary architecture 101 is illustrated for computing device 103. The exemplary computing device 103 is divided into two general regions referred to as the user space 105 and the kernel space 107. The kernel space 107 refers to the central part of the operating system 180. The kernel space 107 typically represents that portion of the operating system 180 that directly accesses the hardware of the computing device 103. In contrast, the user space 105 represents portions of the computing device 103 that interact with software and data received from outside the computing device 103. The exemplary architecture 101 shown in FIG. 1, illustrates the components of an exemplary protector system 104 that operates to protect the computing device 103 from rogue or malicious software.
Beginning with the user space 105, the system management module 125 manages security operations on the computing device 103 and can coordinate the functions of the protector system with other security devices that may be coupled to or operating on the computing device 103. If the computing device is coupled to a network 102, as shown in the exemplary architecture in FIG. 1, the system management module 125 can also be used to coordinate security settings and responses with other components on the network 102. The system management module 125 can also comprise a list of programs and processes that are allowed to run on the computing device 103.
In the user space 105, the command line interface 120 and the protector application 115 are coupled to the system management module 125. The command line interface 120 is typically implemented as a wrapper around the protector API library 117. The primary purpose of the command line interface 120 is to configure various security settings, such as how to respond to a certain threat, and to load the settings into the protector driver management interface 145. The protector application 115 communicates with the protector driver management interface 145 via the API library 117 and provides user-level services in the protector system 104. The protector application 115 can provide the initial configuration load when the protector system 104 is initialized and can interact with a user on certain security decisions. The protector application 115 also interacts with database 110. The database 110 can comprise various data used in performing protector security functions, which will be described in greater detail in connection with FIG. 2.
Communication between the user space 105 and the kernel space 107 is performed with the API library 117 and the protector driver management interface 145. The API library is preferably implemented as a C level application programming interface that allows various processes to maintain the data in database 110 and provide instructions to the drivers in the kernel space 107.
The binary execution monitor 125 implements the primary functions of the protector system 104. The binary execution monitor 125 is an in-kernel driver that monitors the loading of binary executable files and other executable libraries in real time by recognizing and validating any executable file that is being loaded. Validation of an executable file is implemented with the validity module 108 and can be performed using a variety of techniques described in greater detail herein. When the binary execution monitor 125 is installed, it establishes the presence of its processing at the system process-creation hooks 170 within the kernel where it can observe all process and creation activities. When a program is initially loaded into memory in anticipation of execution, the binary execution monitor 125 works with the validity module 108 to validate the program. Using the system process-creation hooks 170, the binary execution monitor 125 can recognize the initial loading of executable files, and any subsequent loading of executable libraries that can occur while a program is executing. The binary execution monitor's 125 functions performed prior to execution of an executable file can also be generally described as being performed by a pre-execution module of the protector system 104.
If the binary execution monitor 125 is unable to validate a program, the detect drivers 153 can monitor the non-validated program when it is executing and identify potential threats to the computing device 103 before they are executed. The detect drivers 153 are plug-in modules linked to the system call hooks 175 within the kernel. The detect drivers 153 communicate system call hooks, using component interface 150, to associated behavior monitoring modules 128 that can react to the suspicious activities. The binary execution monitor 125 also works in conjunction with the behavior monitoring modules 128 to analyze and respond to system call hooks communicated from the detect drivers 153. The behavior monitoring modules 128 are a collection of in-kernel modules that are associated with the detect drivers 153. For example, the privacy monitor 130 reacts to a program's attempt to use a network connection to other computer systems. The file protection monitor 135 can react to an attempt to alter a specified file. The registry protection monitor 140 protects against unauthorized changes to registry settings. Generally, the behavior monitors 128 can take direct action to address a security threat or instruct the protector application 115 to query the user for instructions on how to handle the threat. Other behavior monitors 128 and their associated detect drivers 153 can be plugged into the protector system 104 to implement different security functions. Furthermore, those skilled in the art will understand that the architecture 101 of the protector system 104 shown in FIG. 1 is an example and that various components can be located external to the computing device 103 or on the network 102 in other embodiments. The functions of the binary execution monitor 125, the detect drivers 153, and the behavior monitors 128 performed during execution of an executable file can generally be referred to as being performed by an execution module of the protector system 104.
FIG. 2 illustrates components of the database 110 in accordance with an exemplary embodiment of the protector system 104. The exemplary database 110 comprises checksum data 205, user action data 210, configuration settings 215, and file lock data 220. The checksum data 205 comprises data for each executable that is permitted to run on the computing device 103. The checksum data 205 is used to validate executable files before they are run on the computing device 103. The user action data 210 comprises a record of the user's responses to the introduction of a new executable on the computing device 103. For example, an executable being loaded onto the computing device 103 may not be on a list of allowed programs. If this executable has previously been loaded onto the computing device 103 and the user has been queried as to whether or not the executable is allowed to run, the user's response to this query can be stored in the user action data 210. The configuration settings 215 comprise settings that can be controlled by the user for determining how the protector system 104 will respond to new or suspicious programs being loaded onto the computing device 103. The file lock data 220 represents files selected by the user or network administrator that are to be restricted from access by programs running on the computing device 103. As illustrated in greater detail in the discussion associated with FIG. 7, the file protection monitor 140 can use the file lock data 220 to protect certain files from being accessed.
Referring to FIG. 3, an exemplary setup process 300 is illustrated. The setup process 300 is typically performed prior to the protector system 104 operating on the computing device 103. In step 305 of exemplary process 300, the user stores a list of allowed executable files in the system management module 125. This list of allowed executable files is associated with programs that are approved to run on the computing device 103. The list of allowed executable files may be defined by the user or by a network manager if the computing device 103 is coupled to a network, such as in a workplace environment. In step 310, the user can set access rights for each of the allowed executable files. The access rights for the allowed executable files define which components of the computing device 103, or the network to which the computing device is coupled, may be accessed by that executable. Defining access rights can also include defining which files are restricted from access.
Steps 315 and 320 provide specific examples of validation steps conducted during the setup process using the validity module 108. The binary execution monitor 125 works with the validity module 108 to validate each of the allowed executable files. The validation module 108 can be any one of a variety of pieces of software that are used to verify that a program has not been tampered with. For example, the validation module can represent the MD5 software module commonly known to those in the art. The MD5 software module calculates a checksum for each allowed program and that checksum is stored for later comparison. As described in connection with FIG. 2, the checksum data 205 can be stored in database 110 in step 320.
Finally, in step 325 of the setup process 300, the configuration settings chosen by the user are stored in the database 110. The configuration settings can be chosen by the user of the computing device 103 or by a network administrator if the computing device 103 is coupled to a network. The configuration settings can include predetermined responses to particular threats and decision rules as to when the user should be queried about a security threat.
The subject matter of the remaining drawings, FIGS. 4A, 4B, 5, 6 and 7, generally can be categorized in two phases of execution of a program. The first phase, called pre-execution, occurs as a program is being loaded into memory, but before it can execute. The second phase is the execution process for the program. One advantage of the protector system 104 is that it performs the majority of the security decision-making in the pre-execution process illustrated in FIGS. 4A, 4B and 5. By moving much of the security decision-making to the pre-execution process, the protector system 104 enables the execution process, represented by FIGS. 6 and 7, to run more smoothly and with fewer interruptions for the user.
Referring to FIG. 4A, an exemplary process 400 is illustrated for performing the steps in the pre-execution phase for an executable file. Beginning with step 405, the user, or another software module, may attempt to load a new executable file for running on the computing device 103. In step 410, the kernel begins loading the new executable file into memory in anticipation of running the program. As the executable file is loading, a system process-creation hook 170 notifies the binary execution monitor 125 of the loading process. By initiating the monitoring process at the kernel level, the protector system 104 is able to begin performing its functions before the program can execute and cause possible harm.
In step 420, the kernel will determine whether this executable is already running on the computing device 103. If in fact the executable is running, the “yes” branch is followed to step 425 and the executable will not be loaded. If the executable is already running, it has been approved previously and the protector system 104 can skip the validation process described in connection with FIG. 4B. If however, the executable has not already been loaded, the binary execution monitor 125 will respond to the system process-creation hook 170 by suspending execution of the executable file, in step. 430, until the program can be validated.
The pre-execution process performed by the binary execution monitor 125 and the other associated components of the protector system 104 supports an initial determination of whether the new executable is safe for loading onto the computing device 103. Continuing with FIG. 4B, step 435 illustrates a representative step for validating the new executable. Step 435 will be described in greater detail in one exemplary embodiment in the discussion in connection with FIG. 5 below. In step 440, if the binary execution monitor 125 is able to validate the new executable, the suspended state will be released in step 445 and loading of the executable will continue in step 450. However, if the binary execution monitor 125 is unable to validate the executable in the pre-execution process, additional precautionary steps will have to be taken in the execution phase as described in greater detail in connection with FIGS. 6 and 7.
Referring to FIG. 5, the exemplary process referred to in step 435 is illustrated in greater detail. As mentioned earlier, the checksum technique illustrated in FIG. 5 is only one example of a method for validating an executable. Other validation techniques can use various software modules to analyze the behavior or characteristics of certain executable files in order to validate them. In step 510, the binary execution monitor 125 retrieves the checksum data that was previously calculated and stored in database 110. In step 515, the binary execution monitor 125 calculates a checksum for the new executable which is being loaded on the computing device 103. If the executable is associated with an allowed program, and the program has not been corrupted, the binary execution monitor 125 should find a match between the data contained in the checksum data 205 and the checksum calculated for the new executable. If the binary execution monitor 125 finds a match with the checksum data, the new executable will be found to be valid in step 525. If the program associated with the new executable is not one of the allowed programs designated during the setup process 300, then the executable is found to be not valid in step 530. Additionally, if the executable corresponds to an allowed program but the program has in someway been corrupted, the checksum calculated for the new executable will not match the previously calculated checksum and the new executable is found to be not valid in step 530.
As mentioned above, the exemplary processes illustrated in FIG. 6 and FIG. 7 occur after the pre-execution process and concern executable files that the binary execution monitor 125 could not not validate in the pre-execution phase. Referring to FIG. 6, an exemplary process 600 is illustrated for executing an executable file that has not been validated. Once the pre-execution process 400 terminates and the suspended state is lifted, in step 605 the protector application 115 will consult the database 110 to determine if the user has been previously queried about the new non-validated executable file. If the user has been previously queried about this executable and the previous decision was to not allow this executable file to load, the executable will be terminated in step 620 without interrupting the user for a decision. If the user has previously approved the loading of this executable file in step 610, or, if the user approves the new executable in this instance in step 615, then execution of the executable file will proceed.
Although the user has allowed the non-validated executable file to proceed, the protector system 104 will take steps to protect the computing device 103 and the network 102 that it may be connected to. Steps 625 through 645 illustrate exemplary processes that may be performed in allowing the non-validated executable file to proceed. In step 625, the protector application 115 will notify the system management module 125 that the non-validated executable file is allowed to execute. This notification will serve to allow the system management module 125 to take any precautions, in step 630, to protect other components of the computing device 103 or other network components coupled to the computing device. In step 635, the binary execution monitor 125 will release the suspended state for the new executable and the program will continue to load and execute in step 640.
As the program is executing, the other components of the protector system 104, such as the detect drivers 153 and the behavior monitoring modules 128, operate to prevent the non-validated program from performing any malicious activities on the computing device 103 or on the network 102. The detect drivers 153 are linked to the kernel activities through system call hooks 175. In step 645, certain activities performed by the program will trigger system call hooks that, in turn, trigger the detect drivers 153. The detect drivers 153 are then coupled to the behavior monitoring modules 128, which can observe the program's behavior and respond to any malicious activity. An exemplary process 645 for triggering a detect driver 153 is illustrated in greater detail in FIG. 7.
Referring to FIG. 7, an exemplary detection process 645 is illustrated that employs the file input/output detector 160. The exemplary process 645 is illustrative of the operations of detect drivers 153 and their associated behavior monitors 128. In step 705, the executable file attempts to open a file in connection with a process or activity it is performing. As the kernel attempts to follow the instruction of the executable and open the file, the system call hook 175 linked to this activity triggers the file input/output detector 160 in step 710. The file input/output detector 160, in turn, notifies the file protection monitor 135 in step 715.
Any files that have restricted access, as determined by the user or network administrator in the setup process 300, will be identified in the file lock data in database 210. The file protection monitor 135 consults the file lock data in step 720 to determine whether the subject file has been restricted. If the file is not restricted, the file protection monitor 135 permits the system call hook 175 to proceed with opening the file. However, if the file does appear in the file lock data 220 in step 735, the file protection monitor can limit access to the file. For instance, the file protection monitor can provide read-only access to a file or can prohibit access entirely.
In other examples of how the behavior monitors function, the type of response can depend on the type of activity that is detected as well as the configuration settings 215 selected by the user or the network administrator. For instance, if the program is attempting to perform functions that may seriously impair the computing device 103 or the network 102, the protector system 104 may immediately terminate execution of the program. Alternatively, if the file protection monitor 135 determines that the threat is less severe, the protector application 115 may simply query the user to insure that it is safe to continue executing the program.
In conclusion, the present invention enables and supports security from malicious software programs for a computing device or computing network. The two-step process of the protector system provides an effective and efficient method for implementing security while minimizing the burdens and interruptions for the user. The pre-execution process provides an efficient method for determining whether an uncorrupted program is allowed to execute. By validating certain programs during the pre-execution process, the protector system minimizes the amount of work that must be done in monitoring and controlling programs during the execution phase. The validation step also reduces the number of false positive alarms, thereby reducing security interruptions for the user.
It will be appreciated that the present invention fulfills the needs of the prior art described herein and meets the above-stated objects. While there has been shown and described the preferred embodiment of the invention, it will be evident to those skilled in the art that various modifications and changes may be made thereto without departing from the spirit and the scope of the invention as set forth in the appended claims and equivalence thereof. Although the present invention has been described as operating on a computing device coupled to a network, it should be understood that the invention can be applied to other types of distributed computing environments. Furthermore, it should be readily apparent that the components of the protector system can be located in various local and remote locations of a distributed computing environment.

## Claims

1. A computer-implemented method for implementing security for a computing device comprising the steps of:
receiving a notification that a new program is intended for execution on the computing device;
determining automatically whether the new program is substantially the same as a program which was previously approved for execution on the computing device;
permitting the new program to execute on the computing device similarly to the approved program in response to the new program being substantially the same as the approved program; and
monitoring the execution of the new program at an operating system kernel by permitting the new program to execute on the computing device in response to the new program not being substantially the same as the approved program, wherein the new program is prevented from accessing a specific type of file, using a specific registry setting or making a specific type of network communication that was permitted to the approved program.

2. The computer-implemented method of claim 1, further comprising the steps of computing a checksum for the new program; and comparing the checksum for the new program to a checksum for the program which was previously approved for execution on the computing device.

3. The computer-implemented method of claim 1, further comprising the step of determining if the new program has been modified.

4. The computer-implemented method of claim 1, further comprising the step of terminating execution of the new program in response to the new program performing suspicious activities.

5. A computer system for implementing security for a computing device, said system comprising:
a processor, a random access memory, and a storage device;
first program instructions for receiving a notification that a new program is intended for execution on the computing device;
second program instructions for automatically determining whether the new program is substantially the same as a program which was previously approved for execution on the computing device;
third program instructions, responsive to the new program being substantially the same as the approved program, for permitting the new program to execute on the computing device similarly to the approved program;
fourth program instructions, responsive to the new program not being substantially the same as the approved program, for monitoring the execution of the new program at an operating system kernel by permitting the new program to execute on the computing device while preventing the new program from accessing a specific type of file, using a specific registry setting or making a specific type of network communication that was permitted to the approved program; and
wherein the first, second, third, and fourth program instructions are stored in the storage device for execution by the processor via the random access memory.

6. The computer system of claim 5, wherein the second program instructions comprise program instructions for computing a checksum for the new program, and comparing the checksum for the new program to a checksum for the program which was previously approved for execution on the computing device.

7. The computer system of claim 5, wherein the second program instructions comprise program instructions for determining if the new program has been modified.

8. The computer system of claim 5, wherein the fourth program instructions comprise program instructions for terminating execution of the new program in response to the new program performing suspicious activities.

9. A computer-readable storage media for implementing security for a computing device, said computer-readable storage media comprising:
first program instructions to receive a notification that a new program is intended for execution on the computing device;
second program instructions to automatically determine whether the new program is substantially the same as a program which was previously approved for execution on the computing device;
third program instructions, responsive to the new program being substantially the same as the approved program, to permit the new program to execute on the computing device similarly to the approved program; and
fourth program instructions, responsive to the new program not being substantially the same as the approved program, to monitor the execution of the new program at an operating system kernel by permitting the new program to execute on the computing device while preventing the new program from accessing a specific type of file, using a specific registry setting or making a specific type of network communication that was permitted to the approved program; and wherein said first, second, third and fourth program instructions are stored in said computer-readable storage media.

10. The computer-readable storage media of claim 9, wherein the second program instructions comprise program instructions to compute a checksum for the new program, and to compare the checksum for the new program to a checksum for the program which was previously approved for execution on the computing device.

11. The computer-readable storage media of claim 9, wherein the second program instructions comprise program instructions to determine if the new program has been modified.

12. The computer-readable storage media of claim 9, wherein the fourth program instructions comprise program instructions to terminate execution of the new program in response to the new program performing suspicious activities.