# US 9,519,778 B2 · Systems, methods, and media for outputting a dataset based upon anomaly detection

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- Number: US 9,519,778 B2
- Document ID: US9519778B2
- Status: Granted
- Kind: B2
- Application number: 13/769,774
- Filed: 2013-02-18
- Published: 2014-03-20
- Granted: 2016-12-13
- Earliest claimed: 2006-02-28
- Assignees: The Trustees of Columbia University in the City of New York
- Applicants: The Trustees of Columbia University in the City of New York
- Inventors: Salvatore J Stolfo; Ke Wang; Janak Parekh
- Web page: https://patentgrep.com/patent/US9519778B2

## CPC

- G06F 21/56: Computer malware detection or handling, e.g. anti-virus arrangements
- G06F 21/564: {by virus signature recognition}
- H04L 63/1416: {Event detection, e.g. attack signature detection}
- H04L 63/1425: {Traffic logging, e.g. anomaly detection}
- G06F 2221/034: Test or assess a computer or a system
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Systems, methods, and media for outputting a dataset based upon anomaly detection are provided. In some embodiments, methods for outputting a dataset based upon anomaly detection: receive a training dataset having a plurality of n-grams, which plurality includes a first plurality of distinct training n-grams each being a first size; compute a first plurality of appearance frequencies, each for a corresponding one of the first plurality of distinct training n-grams; receive an input dataset including first input n-grams each being the first size; define a first window in the input dataset; identify as being first matching n-grams the first input n-grams in the first window that correspond to the first plurality of distinct training n-grams; compute a first anomaly detection score for the input dataset using the first matching n-grams and the first plurality of appearance frequencies; and output the input dataset based on the first anomaly detection score.

## Claims

### Claim 1

A method for outputting a dataset based upon anomaly detection, the method comprising:
receiving, using a hardware processor, an input dataset;
determining, using the hardware processor, an anomaly detection score that is indicative of the presence of anomalous n-grams in the input dataset by applying a content anomaly detection model to the received input data, wherein the content anomaly detection model is trained with data that includes training n-grams and wherein the anomaly detection score is based on a comparison of n-grams in the input dataset, which each represent a sequence of n bytes, with the training n-grams; and
causing, using the hardware processor, the input dataset to be outputted based on the anomaly detection score.

### Claim 2 (depends on 1)

The method of claim 1, wherein the content anomaly detection model is a frequency distribution-based detection model that determines a plurality of appearance frequencies, and wherein each of the plurality of appearance frequencies corresponds to one of the training n-grams.

### Claim 3 (depends on 2)

The method of claim 2, wherein the training n-grams include a first plurality of distinct training n-grams and a second plurality of distinct training n-grams.

### Claim 4 (depends on 3)

The method of claim 3, further comprising:
determining a first plurality of appearance frequencies corresponding to the first plurality of distinct training n-grams; and
determining a second plurality of appearance frequencies corresponding to the second plurality of distinct training n-grams; and
determining a first anomaly detection score based on the first plurality of appearance frequencies and a second anomaly detection score based on the second plurality of appearance frequencies.

### Claim 5 (depends on 4)

The method of claim 4, further comprising:
determining which of the first anomaly detection score and the second anomaly detection score is higher; and
outputting the input dataset based on the anomaly detection score that is higher.

### Claim 6 (depends on 1)

The method of claim 1, wherein the content anomaly detection model is a binary-based detection model that determines a number of distinct n-grams in the input dataset and a total number of n-grams contained in the input dataset.

### Claim 7

A system for outputting a dataset based upon anomaly detection, the system comprising:
a hardware processor that:
receives an input dataset;
determines an anomaly detection score that is indicative of the presence of anomalous n-grams in the input dataset by applying a content anomaly detection model to the received input data, wherein the content anomaly detection model is trained with data that includes training n-grams and wherein the anomaly detection score is based on a comparison of n-grams in the input dataset, which each represent a sequence of n bytes, with the training n-grams; and
causes the input dataset to be outputted based on the anomaly detection score.

### Claim 8 (depends on 7)

The system of claim 7, wherein the content anomaly detection model is a frequency distribution-based detection model that determines a plurality of appearance frequencies, and wherein each of the plurality of appearance frequencies corresponds to one of the training n-grams.

### Claim 9 (depends on 8)

The system of claim 8, wherein the training n-grams include a first plurality of distinct training n-grams and a second plurality of distinct training n-grams.

### Claim 10 (depends on 9)

The system of claim 9, wherein the system is further configured to:
determine a first plurality of appearance frequencies corresponding to the first plurality of distinct training n-grams; and
determine a second plurality of appearance frequencies corresponding to the second plurality of distinct training n-grams; and
determine a first anomaly detection score based on the first plurality of appearance frequencies and a second anomaly detection score based on the second plurality of appearance frequencies.

### Claim 11 (depends on 10)

The system of claim 10, wherein the system is further configured to:
determine which of the first anomaly detection score and the second anomaly detection score is higher; and
output the input dataset based on the anomaly detection score that is higher.

### Claim 12 (depends on 7)

The system of claim 7, wherein the content anomaly detection model is a binary-based detection model that determines a number of distinct n-grams in the input dataset and a total number of n-grams contained in the input dataset.

### Claim 13

A non-transitory computer-readable medium containing computer-executable instructions that, when executed by a processor, cause the processor to perform a method for outputting a dataset based upon anomaly detection, the method comprising:
receiving an input dataset;
determining an anomaly detection score that is indicative of the presence of anomalous n-grams in the input dataset by applying a content anomaly detection model to the received input data, wherein the content anomaly detection model is trained with data that includes training n-grams and wherein the anomaly detection score is based on a comparison of n-grams in the input dataset, which each represent a sequence of n bytes, with the training n-grams; and
causing the input dataset to be outputted based on the anomaly detection score.

### Claim 14 (depends on 13)

The non-transitory computer-readable medium of claim 13, wherein the content anomaly detection model is a frequency distribution-based detection model that determines a plurality of appearance frequencies, and wherein each of the plurality of appearance frequencies corresponds to one of the training n-grams.

### Claim 15 (depends on 14)

The non-transitory computer-readable medium of claim 14, wherein the training n-grams include a first plurality of distinct training n-grams and a second plurality of distinct training n-grams.

### Claim 16 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the method further comprises:
determining a first plurality of appearance frequencies corresponding to the first plurality of distinct training n-grams; and
determining a second plurality of appearance frequencies corresponding to the second plurality of distinct training n-grams; and
determining a first anomaly detection score based on the first plurality of appearance frequencies and a second anomaly detection score based on the second plurality of appearance frequencies.

### Claim 17 (depends on 16)

The non-transitory computer-readable medium of claim 16, wherein the method further comprises:
determining which of the first anomaly detection score and the second anomaly detection score is higher; and
outputting the input dataset based on the anomaly detection score that is higher.

### Claim 18 (depends on 13)

The non-transitory computer-readable medium of claim 13, wherein the content anomaly detection model is a binary-based detection model that determines a number of distinct n-grams in the input dataset and a total number of n-grams contained in the input dataset.
