Classic antivirus answers the question of whether a file is known to be malicious. Endpoint detection and response answers a different one: whether a sequence of activity on a system departs from what is expected. For compliance, though, the decisive capability is the third one implied in the name and usually lost in the discussion: the recording that lets you reconstruct afterwards what actually happened.
That sentence is worth carrying into a budget conversation. EDR is rarely bought as an audit control, and it is one of the few technical purchases that materially changes what you are able to say in a regulatory notification.
Detect, investigate, respond
The capability falls into three layers. Detection evaluates process starts, file access and network connections on the endpoint and raises alerts on deviations. Investigation draws on the recorded activity: it shows which action triggered which other action and which data was touched. Response ranges from isolating a system, through terminating a process, to rolling back changes.
The middle layer is the most valuable from an assurance point of view. Without it, the question of which data was affected stays open after an incident, and that question is precisely what decides whether a notification is required and what it has to contain.
Where this sits in regulation
EDR is not mandated anywhere. What is mandated is being able to handle security incidents: the catalogue of measures in § 30(2) sentence 2 BSIG names in no. 2 the handling of security incidents, and Art. 32 GDPR requires measures appropriate to the risk. The real connection runs through the reporting duties. A notification under § 32 BSIG, or notification of a personal data breach, calls for details on the nature and extent of the incident. An organisation that cannot evidence those details either over-reports or reports too vaguely, and neither is a good position.
There is a timing dimension as well. All reporting deadlines run from the point of becoming aware. Detection on the endpoint shortens the time to awareness and at the same time supplies the evidence of when that point was.
What auditors ask
Three topics dominate. First, coverage: on what proportion of systems is detection active, and how is that checked on an ongoing basis? Servers, systems in manufacturing environments and service providers' devices are the usual gaps. Second, the handling path: who receives an alert, within what time, and what happens outside normal working hours? Third, the authority to respond: who may isolate a system, and is that authority arranged so that it is actually exercised when it counts? The technical ability to take a production system off the network is worth little while the decision to do so is unsettled.
A fourth question concerns retention of the recorded data. It is personal data, because it depicts what people do at a workstation. Purpose, access and retention period therefore have to be governed as they would be for any other logging, and introducing the capability may be subject to co-determination (in Germany, the works council's participation rights), which is a matter for legal review in the individual case.
Evidence that holds
A coverage report as at a given date, reconciled against the system inventory; documented handling of the systems not covered; an evaluation of alerts over a sample period, with handling status and handling time; the link into the incident process including escalation; the rules on purpose, access and retention of the recorded data; and the result of an exercise in which isolating a system was actually rehearsed.
Relationship to a SIEM
The two are often weighed against each other although they answer different questions. EDR sees very precisely what happens on a single system, but only there. A SIEM sees less precisely, but across system boundaries: it links an event on the endpoint with a sign-in at the directory service and a connection at the network boundary. EDR supplies one of the most valuable sources for that cross-system evaluation. Where only one of the two can be operated, the decision should follow from your own risk picture and the reasoning should be documented; in an audit, a justified selection holds up better than a full stack run incompletely.
Limits
EDR replaces neither hardening nor patching nor segmentation. It comes into play after the preventive measures have failed, which makes it the second line of defence rather than the first. Nor does it replace backup: rolling back changes is limited to what was recorded, and covers neither encrypted data stores nor damaged backups.
Where evaluation is contracted out to a service provider, the same applies as to any outsourcing: the task moves, the responsibility stays. Delimited responsibilities, agreed response times, a governed handover into your own incident process and a periodic review of service delivery are the points an audit will press on.
Where Rizzqo sits alongside a detection tool
The points of contact with the EDR or XDR product in use lie before and after detection, and both are commonly under-staffed.
Before comes the coverage question. Whether an agent runs on every relevant system can only be judged against a complete inventory, and that exists in Rizzqo as a set of classified objects with named owners. A group of servers without coverage shows up as an open requirement on the object concerned. After comes the consequence: a recurring finding can be carried as a risk assessment with a likelihood and an impact in euros and worked off through tasks whose planned reduction only takes effect on completion.