Deriving statistically probable and statistically relevant indicator of compromise signature for matching engines

Abstract

Methods and systems are provided for a histogram model configuring a computing system to derive an indicator of compromise signature based on a sliding window index of identified malware samples, and a matching rule constructor configuring a computing system to generate matching signatures by selecting statistically relevant n-grams of an unidentified file sample. A matching rule constructor configures the computing system to construct a matching rule including, as a signature, 32 n-grams found in the unidentified file sample which occur most frequently, and another 32 n-grams found in the unidentified file sample which occur least frequently amongst records of the threat database across 32 discrete file size ranges. These functions can configure backend operations to a sample identification operation performed by a user operating a client computing device, in a fashion that does not require a user to manually discern strings from the unidentified file sample to derive a signature for the matching engine to search against the threat database.