Crowdstrike, Inc.

Daniel Radu

Horea Coroiu

Marian Radu

George Robert Kurtz

Amol Kulkarni

Radu Cazan

Jan Miller

Dmitri Alperovitch

A security service can determine a synthetic context based at least in part on context data associated with a first malware sample, and detonate the first malware sample in the synthetic context to provide one or more first event records representing events performed by the first malware sample and detected during detonation. Additionally or alternatively, the security service can detonate the first malware sample and locate a second malware sample in a corpus based at least in part on the one or more first event records. Additionally or alternatively, the security service can receive event records representing events detected during a detonation of a first malware sample, the detonation based at least in part on context data, and locate a second malware sample in the corpus based at least in part on the one or more reference event records.

Analysis of malware

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.

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

Training and use of a byte n-gram embedding model is described herein. A neural network is trained to determine a probability of occurrence associated with a byte n-gram. The neural network includes one or more embedding model layers, at least one of which is configured to output an embedding array of values. The byte n-gram embedding model may be used to generate a hash of received data, to classify the received data with no knowledge of a data structure associated with the received data, to compare the received data to files having a known classification, and/or to generate a signature for the received data.

Byte n-gram embedding model

Techniques for searching an inverted index associating byte sequences of a fixed length and files that contain those byte sequences are described herein. Byte sequences comprising a search query are determined and searched in the inverted index. In some examples, training data for training machine learning model(s) may be created using pre-featured data from the inverted index. In various examples, training data may be used to retrain a ML model until the ML model meets a criterion. In some examples, the trained ML model may be used to perform searches on the inverted index and classify files.

Applications of machine learning models to a binary search engine based on an inverted index of byte sequences

Techniques for searching an inverted index associating byte sequences of a fixed length and files that contain those byte sequences are described herein. Byte sequences comprising a search query are determined and searched in the inverted index, and an intersection of the results is determined and returned as a response to the search query. Further, search queries in the form of expressions including search terms and logical operators are searched in the inverted index and evaluated using a syntax tree constructed based on the logical operators. Also, byte sequences comprising a file are searched in the inverted index and results of the search are used to generate signatures and fuzzy hashes.

Binary search of byte sequences using inverted indices

Techniques for searching an inverted index associating byte sequences of a fixed length and files that contain those byte sequences are described herein. Byte sequences comprising a search query are determined and searched in the inverted index. In some examples, the inverted index may be distributed across multiple computers and the search may be performed in parallel. In some examples, a search query may be submitted as expressions comprising query language or regular expressions that are interpreted as search terms, transformed into byte sequences, and searched for in the inverted index. In some examples, an automatic notification request for a search query may be processed and notifications may be sent based on a default or preferred frequency and method.

Growing community of inventors

Bucharest, Romania

Daniel Radu