
Initially, the PVS has no knowledge of your network’s active hosts. The first packets that the PVS sniffs would send an
alert. To avoid this, the PVS can be configured to learn the network over a period of days. Once this period is over, any
“new” traffic would be from a host that has not communicated during the initial training.
To prevent the PVS from having to relearn the network each time it starts, a file can be specified to save the active host
information. This file contains a list of all the current active hosts for the PVS. The scanner also requires that an interval to
update this file be specified. Tenable recommends an update time of at least one day (1440 minutes).
When the PVS logs a new host, the Ethernet address is saved in the message. When the PVS is more than one
hop away from the sniffed traffic, the Ethernet address will be that of the local switch, not the actual host. If the
scanner is deployed in the same collision domain as the sniffed server, the Ethernet address will be accurate.
For DHCP networks, the PVS will detect a “new” host very often. Tenable recommends deploying this feature
on non-volatile networks such as demilitarized zone (DMZ). Users should also consider analyzing PVS “new”
host alerts with Tenable’s SecurityCenter, which can sort real-time PVS events by networks.
Internal Passive Vulnerability Scanner IDs
What is a Passive Vulnerability Scanner ID?
This section describes the PVS’s advanced signature language for each plugin. Each vulnerability and real-time check
that the PVS performs has a unique associated ID. Since Tenable manages the Nessus vulnerability scanner, we have
added the IDs used by the PVS into the overall Nessus architecture. PVS IDs start from #00000 and go through #10000.
Nessus IDs start from #10001 and extend upward.
Internal Passive Vulnerability Scanner IDs
Some of the PVS’s checks, such as detecting open ports, are built in. The following chart lists some of the more
commonly encountered internal checks and describes what they mean:
The PVS has observed a SYN-ACK leave from a server.
The PVS has observed enough traffic about a server to perform a guess of the
operating system.
The PVS has observed browsing traffic from a host.
Internal Client Trusted
Connections
The PVS has logged a unique network session of source IP, destination IP and
destination port.
Internal Interactive
Sessions
The PVS has detected one or more interactive network sessions between two
hosts within your focus network.
Outbound Interactive
Sessions
The PVS has detected one or more interactive network sessions originating from
within your focus network and destined for one or more addresses on the Internet.
Inbound Interactive
Sessions
The PVS has detected one or more interactive network sessions originating from
one or more addresses on the Internet to this address within your focus network.
Internal Encrypted
Session
The PVS has detected one or more encrypted network sessions between two
hosts within your focus network.
Kommentare zu diesen Handbüchern