Introduction to the ExtraHop system

L2 Discovery

In L2 Discovery, the ExtraHop system creates a device entry for every local MAC address discovered over the wire. IP addresses are mapped to the MAC address, but metrics are stored with the device MAC address even if the IP address changes.

IP addresses observed outside of locally-monitored broadcast domains are aggregated at one of the incoming routers in your network. If a device sends a DHCP request through a router acting as a DHCP relay agent, the ExtraHop system detects and maps the IP address to the device MAC address. If the IP address changes for the device with a subsequent request through the DHCP relay agent, the ExtraHop system updates its mapping and continues to keep track of the device metrics by the MAC address.

If a DHCP relay agent is not configured, remote devices can be discovered by their IP addresses through Remote L3 Discovery.

L3 Discovery

In L3 Discovery, the ExtraHop system creates and links two entries for each local discovered device: an L2 parent entry with a MAC address and an L3 child entry with IP addresses and the MAC address.

Here are some important considerations about L3 discovery:

• If a router has proxy ARP enabled, the ExtraHop system creates an L3 device for each IP address that the router answers ARP requests for.
• If you have a proxy ARP configured in your network, the ExtraHop system might automatically discover remote devices.
• L2 metrics that cannot be associated with a particular L3 child device (for example, L2 broadcast traffic) are associated with the L2 parent device.

Remote L3 Discovery

If the ExtraHop system detects an IP address that does not have associated ARP or NDP traffic, that device is considered a remote device. Remote devices are not automatically discovered, but you can add a remote IP address range and discover devices that are outside of the local network. A device entry is created for each IP address that is observed within the remote IP address range. (Remote devices do not have L2 parent entries.)

Here are some recommendations about when to configure Remote L3 Discovery:

• Your client devices are on a network segment that is not directly tapped.
• Your organization has a remote office without an on-site ExtraHop system but users at that site access central data center resources that are directly monitored by an ExtraHop system. The IP addresses at the remote site can be discovered as devices.
• A cloud service or other type of off-site service hosts your remote applications and has a known IP address range. The remote servers within this IP address range can be individually tracked.

VPN Discovery

VPN Discovery enables the ExtraHop system to correlate the private, RFC-1918 IP addresses assigned to VPN clients with their public, external IP addresses. This enriched visibility into north-south traffic reduces barriers when investigating security incidents and performance issues that involve external VPN clients. (This feature requires a VPN gateway that is manually assigned by the user.)

Detection Tuning

Reduce noise and surface only critical detections by adding details about your network that help identify known parameters such as trusted domains and vulnerability scanners.

Additionally, you can create tuning rules that hide specific detections or participants and further reduce unwanted noise.

Network Locality

By default, any device with an RFC1918 IP address (included in a 10/8, 172.16/12, or 192.168/16 CIDR block) is classified on the system as an internal device.

However, because some network environments include non-RFC1918 IP addresses as part of their internal network, you can change the internal or external classification for IP addresses from the Network Localities page.

Threat Intelligence

The ExtraHop system includes a curated threat intelligence feed that is updated through the cloud as new threats are discovered. You can also add threat collections from a third-party or through partner integrations with ExtraHop Reveal(x) 360.

Threat Briefings

Threat briefings provide information about imminent threats that are targeting networks. Updated detections, targeted record and packet queries, and affected devices are presented as a starting point for your investigation, accessed from the Security Overview page.

Integrations

Reveal(x) 360 provides several third-party integrations that can enhance detection and response management and provide better visibility into network traffic.

Microsoft Protocol Decryption

Enable decryption of Microsoft protocol traffic and improve detection of security attacks within your Microsoft Windows environment. ExtraHop Reveal(x) 360 synchronizes encryption keys with Windows domain controllers to decrypt and analyze network traffic over protocols such as LDAP, RPC, SMB, and WSMan.

CrowdStrike

Import threat intelligence from CrowdStrike Falcon X into the ExtraHop system to detect and annotate indicators of compromise in your environment. You can also easily navigate from assets in the ExtraHop system that are running CrowdStrike to the CrowdStrike Falcon console.

Microsoft 365 (Beta)

Import Microsoft 365 and Azure Active Directory detections and events into the ExtraHop system. You can also monitor Microsoft 365 metrics in built-in dashboards and view risk event details in records.

Splunk

Export and view ExtraHop detections in your Splunk SIEM.

QRadar

Export and view ExtraHop detections in your QRadar SIEM.