Crowdstrike, Inc.

Ion-Alexandru Ionescu

Aaron LeMasters

Dmitri Alperovitch

David Frederick Diehl

George Robert Kurtz

Loren C Robinson

Timo Kreuzer

Daniel W Brown

Cameron Gutman

Aaron Lemasters

Satoshi Tanda

A security agent configured to initiate a security agent component as a hypervisor for a computing device is described herein. The security agent component may then determine pages of the memory which include identified memory locations and set privilege attributes of those pages to prevent specific types of access to the memory locations, such as executing code stored at a memory location. Also, the security agent component may refrain from setting intercepts for pages including a whitelisted memory location. Further, the security agent component may set intercepts for debug registers, note read operations from the operating system for those registers, and respond with operating-system-permitted values. Additionally, the security agent component may set intercepts for instructions for performing write operations on control registers.

Hypervisor-based interception of memory and register accesses

A security agent configured to initiate a security agent component as a hypervisor for a computing device is described herein. The security agent component may change a value of a processor configuration register, such as a Model Specific Register (MSR), in order to cause system calls to be redirected to the security agent, and may set an intercept for instructions for performing read operations on the processor configuration register so that a process, thread, or component different from the processor of the computing device may receive the original value of the processor configuration register instead of an updated value of the processor configuration register. The security agent component may also be configured to generate interrupts to offload task execution from the hypervisor to a security agent executing as a kernel-level component.

Hypervisor-based redirection of system calls and interrupt-based task offloading

A bus filter driver and security agent components configured to retrieve and analyze firmware images are described herein. The bus filter driver may attach to a bus device associated with a memory component and retrieve a firmware image of firmware stored on the memory component. The bus filter driver may also retrieve hardware metadata. A kernel-mode component of the security agent may then retrieve the firmware image and hardware metadata from the bus filter driver and provide the firmware image and hardware metadata to a user-mode component of the security agent for security analysis. The security agent components may then provide results of the analysis and/or the firmware image and hardware metadata to a remote security service to determine a security status for the firmware.

Firmware retrieval and analysis

A plug-and-play (PnP) driver associated with a security agent is described herein. The PnP driver attaches to device stacks of enumerated bus devices of a computing device as upper-device or lower-device filters based on the device classes of the enumerated bus devices. For example, the PnP driver may attach to the device stack of a hub or controller device as an upper-device filter and to device stacks of other devices as lower-device filters. Either while attaching or after attachment, the PnP driver may take action to alter, limit, or otherwise block functionality of an enumerated bus device. The PnP driver may also perform a system inventory of enumerated bus devices connected to the computing device and create fingerprints for one or more of the computing devices. Additionally, the PnP driver may create and remove control device objects (CDOs) to enable communication with user-mode processes or threads.

Security component for devices on an enumerated bus

A service proxy is described herein. The service proxy is configured to act as an intermediary between a client and a service. The service proxy may observe communications, modify communications, log communications, or the like, particularly so as to enhance the security and reliability of the host device. In some implementations, the service proxy may cooperate with an operating system to take over a named port object. In some implementations, the service proxy may receive messages as an intermediary between the client and the server. In some implementations, the service proxy may attach to a shared memory to intercept communications. In some implementations, the service proxy may be injected into a client process to appear to be the client itself.

RPC call interception

A security agent executing in kernel mode may receive a request from the anti-malware component executing with low privileges in user mode, and, in response, the security agent may perform a security action with respect to a malicious file detected on the computing device. The security agent may then assist the anti-malware component in providing a user notification about the security action by obtaining, on behalf of the anti-malware component, a user token associated with the user session in which the malicious file was detected. The anti-malware component can use the obtained user token to request a pointer to a Component Object Model (COM) interface for outputting the notification in context of the appropriate user session, which allows for securely and efficiently providing the user notification.

Securely and efficiently providing user notifications about security actions

Some example computing systems herein include two modules, e.g., drivers. A first can instantiate an interface associated with a service routine, receive, by the service routine, a verification message; and send, in response, a confirmation message via the interface. A second can locate the interface; open a handle to the interface; send the verification message via the handle, the verification message identifying at least an interface type or a version; and receive, via the handle, the confirmation message associated with the verification message. In some examples, the first driver is a Plug and Play driver. In some examples, the first module can receive, by the service routine, a command associated with the interface; determine that the command is a valid command based at least in part on stored command data; and send, via the interface, a response to the command.

Verified inter-module communications interface

Techniques are described herein for, without rebooting a computing device, unloading at least a component of a kernel-mode component of the computing device and loading an updated version of the component of the kernel-mode component. The techniques may be performed by an integrity manager associated with the kernel-mode component. The integrity manager may also determine integrity of the kernel-mode component by causing the kernel-mode component to perform an action associated with a known reaction, determining whether the known reaction occurred, and in response, performing a remediation action or notifying a remote security service. Further, the integrity manager may determine whether any computing device lists include representations of components or connections associated with the kernel-mode component. The integrity manager may then remove the representations from the lists or remove the representations from responses to requests for contents of the computing device lists.

Integrity assurance and rebootless updating during runtime

A security agent configured to initiate a security agent component as a hypervisor for a computing device is described herein. The security agent is further configured to determine a subset of memory locations in memory of the computing device to be intercepted. The security agent component may then set intercepts for the determined memory locations. Setting such intercepts may include setting privilege attributes for pages which include the determined memory locations so as to prevent specific operations in association with those memory locations. In response to one of those specific operations, the security agent component may return a false indication of success or allow the operation to enable monitoring of the actor associated with the operation. When an operation affects another memory location associated with one of the pages, the security agent component may temporarily reset the privilege attribute for that page to allow the operation.

Hypervisor-based interception of memory accesses

In some examples, a processing unit can install a second driver to an installed-driver backing store on a non-volatile (nonV) memory, and replace a first driver in a driver store of the nonV memory with the second driver without replacing the first driver in the volatile memory with the second driver. The processing unit can, subsequently, determine that the second driver has been loaded into the volatile memory, and write, by the second driver loaded into the volatile memory, a driver-configuration entry in a configuration datastore. An example computing system can include the first driver in volatile memory, and the nonV memory. The nonV memory can include a driver-configuration file, a driver store holding a first copy of the second driver, and an installed-driver backing store holding a second copy of the second driver. Some examples can roll back failed installation operations.

Device driver non-volatile backing-store installation

A security agent is described herein. The security agent is configured to observe events, filter the observed events using configurable filters, route the filtered events to one or more event consumers, and utilize the one or more event consumers to take action based at least on one of the filtered events. In some implementations, the security agent detects a first action associated with malicious code, gathers data about the malicious code, and in response to detecting subsequent action(s) of the malicious code, performs a preventative action. The security agent may also deceive an adversary associated with malicious code. Further, the security agent may utilize a model representing chains of execution activities and may take action based on those chains of execution activities.

Growing community of inventors

Seattle, WA, United States of America

Ion-Alexandru Ionescu