US 8,413,253 B2Granted

Protecting persistent secondary platform storage against attack from malicious or unauthorized programs

AssigneeIntel Corporation

InventorAkshay R. Kadam

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Abstract

A high integrity storage manager protects critical system files by maintaining a list of protected disk blocks in hardware, such as in a memory of a microcontroller. The memory is inaccessible to software running on a host system comprising the microcontroller. This list of protected disk blocks is protected as “read only” by the hardware so that no write operation issued by software running on the host platform can overwrite a protected disk block. The high integrity storage manager intercepts write operations issued by applications via the operating system and file system running on the host processor and compares the disk blocks targeted by those write operations to the list of protected disk blocks. A write operation that would overwrite a disk block in the list of protected disk blocks is prevented from completion. Other embodiments are described and claimed.

Claims19

Dependent claims

A computer-implemented-method comprising:

maintaining, on a host system, a list of protected disk blocks in a memory of a microcontroller of the host system, wherein the memory is inaccessible to software running on a processor of the host system;
intercepting, on the host system, a write command sent by the software running on the processor to a storage controller of the host system;
inspecting, on the host system, the write command to determine whether the write command attempts to write to a disk block on the list of protected disk blocks;
causing, on the host system, the write command to fail if a result of the determination indicates the write command attempts to write to a disk block on the list of protected disk blocks;
and
in response to receiving, on the host system, a request to update a requested disk block after the requested disk block has been removed from the list of protected disk blocks in response to a remove request received via a secure interface of the host system,
causing, on the host system, external interfaces of the host system for accessing the host system to be disabled;
and
allowing, on the host system, the requested disk block to be updated after the external interfaces have been disabled.

6 more elements

A system comprising:

a processor;
a microcontroller,
having a storage controller and a storage integrity manager, coupled with the processor;
and
a secure interface coupled with the processor and the microcontroller, and configured to provide secure access to the system;
wherein the storage integrity manager is configured to:
maintain, within the microcontroller, a list of protected disk blocks of a disk storage accessed through the storage controller;
intercept a write command sent by software running on the processor to the storage controller;
inspect the write command to determine whether the write command attempts to write to a disk block on the list of protected disk blocks;
cause the write command to fail if a result of the determination indicates the write command attempts to write to a disk block on the list of protected disk blocks;
and
wherein the secure interface is configured to enable a requested disk block on the list of protected disk block to be removed from the list of protected disk blocks, to enable content in the requested disk block to be updated, and to enable the requested disk block to be added back to the list of protected disk blocks after content in the requested disk block has been updated,
wherein the system, in addition to the microcontroller, includes a processor configured to execute an operating system, and an external interface for an external server to access the system, wherein the secure interface and the external interface are different interfaces.

10 more elements

A non-transitory machine-accessible storage medium comprising instructions configured to enable a microcontroller of a host system, in response to execution of the instructions by the microcontroller, to:

maintain, within the microcontroller, a list of protected disk blocks of storage device accessed through a storage controller of the host system;
intercept a write command sent by software running on a processor of the host system to a storage controller;
inspect the write command to determine whether the write command attempts to write to a disk block on the list of protected disk blocks;
cause the write command to fail if a result of the determination indicates the write command attempts to write to a disk block on the list of protected disk blocks;
and
remove a requested block from the list of protected disk blocks, to enable content in the requested disk block to be updated, and add back the requested block to the list of protected disk blocks after content in the requested disk block has been updated, in response to requests received via a secure interface of the host system;
wherein the host system, in addition to the microcontroller, includes a processor configured to execute an operating system, and an external interface for an external server to access the host system;
wherein the secure interface and the external interface are different interfaces.

5 more elements

Dependencies are inferred from the claim text.