At first glance, an XDR tool may look similar to a security incident and event management (SIEM) solution. Both take in telemetry (data) from across an organization’s security stack to better detect existing and emerging threats. However, there are a number of notable differences between the two technologies.
The biggest difference is that XDR tools limit the data they can ingest in order to perform their duties whereas a SIEM solution is designed to take in data from any and all sources. By virtue of their EDR roots, XDR tools ingest data to improve the scope and accuracy of their endpoint threats detections. The technologies integrated into them, such as email, network and cloud workload, are either endpoints, or endpoint adjacent. Information gathered from these types of solutions are used to determine if an endpoint threat is credible. On the other hand, SIEM platforms take in data for threat detection across all parts of the infrastructure.
Another difference between a SIEM platform is that XDR tools are not well suited for investigating emerging and advanced threats or fraud use cases. Investigations tend to span across multiple systems and solutions, often with clues lying in unlikely places as attackers become more creative in hiding their attacks. Not having access to all forms of data can stymie threat hunters as they follow the trail of an attacker and piece together the story of the attack.
Also, unlike SIEM, XDR solutions lack long-term storage capabilities. Whether due to functionality or performance compromises, XDR tools can’t retain data long-term. Consequently, data needs to be stored elsewhere in order to fulfill compliance and auditing requirements faced by enterprises. Compliance mandates such as PCI DSS, NIST CSF, GDPR, HIPAA, and SOX generally require organizations to reduce the risk of data breaches by implementing various security controls, tracking critical business events, defining a security threat response plan, and keeping detailed records of all security events and how they were handled. SIEM, however, provides continuous monitoring, log management, analysis and visualization and real-time threat detection and alerting that help organizations meet these requirements.
XDR tools do provide threat response capabilities that legacy SIEM platforms do not. XDR tools are also typically much easier to assemble and run than a SIEM platform. Because they have a limited set of integrations, vendors can more easily integrate the solutions, in turn easing XDR logistics and management.