US 7,444,677 B2 · Intentional cascade failure

Abstract

Additional code is added to sensitive code in order to foil an adversary attempting to examine or modify the sensitive code. The additional code implements a cascade failure system. In the cascade failure system an intrusion is detected by an authorization check, and when an intrusion is detected, further changes are made which will trigger failures of other authorization checks or cause corruptions to the internal execution state of the program. Eventually, the changes will trigger a complete failure of the code to run correctly, however the genesis of the cascading failure will be concealed, so an adversary will not be able to determine how the intrusion was initially detected. The insertion of the additional cascade failure system code can be performed automatically by a mechanism with some random components, and thus the locations and content of the inserted code may be different for each instance of sensitive code into which a content failure system has been inserted.

Claims9

Dependent claims

A method of protecting sensitive code, comprising:

inserting into said sensitive code a first insertion comprising a first authorization check which, when said sensitive code is executing in a computing environment, detects whether an unauthorized action is occurring;
and a first cascade trigger which, upon said detection of an unauthorized action, changes a first state of said computing environment in a way detectable by a second authorization check;
inserting into said sensitive code a second insertion comprising said second authorization check;
and a second cascade trigger, which upon detection of said changed first state, generates one of a) a stack failure and b) a heap failure;
and
inserting into said sensitive code a third insertion comprising decoy code, wherein said decoy code changes said first state of said computing environment in a way which will not cause any of a group of authorization checks comprising said first authorization check and said second authorization check to detect an unauthorized action if, before said decoy code changes, no authorization check from said group would have detected said unauthorized action.

3 more elements

Dependencies are inferred from the claim text.

Intentional cascade failure

Life of this patent

Intentional cascade failure

Life of this patent

Abstract

Claims9