摘要 |
A computer-implemented apparatus and method for countering attempts of polymorphic viruses to evade detection by emulation-based scanners. Such attempts try to exploit differences between the real and virtual execution of instructions. The invention includes a fault manager (158) integrated into the CPU emulator (154) of a virus scanner software product. Before each instruction is emulated by the CPU emulator (154), the fault manager (158) examines the opcode of the instruction to determine (310) whether a "fault" is triggered. If a fault is triggered, the fault manager (158) saves (314) a state record on a fault stack (162), then interrupts (316) to a corresponding fault handler routine (160). The criteria for triggering a fault and the corresponding fault handler routine (160) may be obtained from an updatable data file (164).
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