Explanation: The threat intelligence standard that contains malware hashes is trusted automated exchange of indicator information (TAXII). TAXII is a protocol that enables the exchange of cyber threat information in a standardized and automated manner. It supports various types of threat intelligence, such as indicators of compromise (IOCs), observables, incidents, tactics, techniques, and procedures (TTPs), and campaigns. Malware hashes are one example of IOCs that can be shared using TAXII. Malware hashes are cryptographic signatures that uniquely identify malicious files or programs. They can be used to detect and block malware infections on endpoints or networks. TAXII uses STIX (structured threat information expression) as the data format for representing threat intelligence. STIX is a language that defines a common vocabulary and structure for describing cyber threat information. STIX allows threat intelligence producers and consumers to share information in a consistent and interoperable way. STIX defines various objects and properties that can be used to represent different aspects of cyber threat information, such as indicators, observables, incidents, TTPs, campaigns, threat actors, courses of action, and relationships. Malware hashes can be expressed as observables in STIX, which are concrete items or events that are observable in the operational domain. Observables can have various types, such as file, process, registry key, URL, IP address, domain name, etc. Each observable type has a set of attributes that describe its properties. For example, a file observable can have attributes such as name, size, type, hashes, magic number, etc. A hash attribute can have a type (such as MD5, SHA1, SHA256, etc.) and a value (such as the hexadecimal representation of the hash). A file observable can have one or more hash attributes to represent different hashing algorithms applied to the same file. For example, a file observable can have both MD5 and SHA256 hashes to increase the confidence and accuracy of identifying the file.
The other options are incorrect because they are not threat intelligence standards that contain malware hashes. Option A is incorrect because advanced persistent threat (APT) is not a standard, but a term that describes a stealthy and sophisticated cyberattack that aims to compromise and maintain access to a target network or system over a long period of time. Option B is incorrect because open command and control (OpenC2) is not a standard that contains malware hashes, but a language that enables the command and control of cyber defense components, such as sensors, actuators, and orchestrators. Option C is incorrect because structured threat information expression (STIX) is not a standard that contains malware hashes, but a data format that represents threat intelligence. STIX uses TAXII as the transport protocol for exchanging threat intelligence, including malware hashes. References: