[PCI DSS 3.0] 11.2 Run internal and external network vulnerability scans at least quarterly and after any signific

11.2 Run internal and external network vulnerability scans at least quarterly and after any significant change in the network (such as new system component installations, changes in network topology, firewall rule modifications, product upgrades).

Note: Multiple scan reports can be combined for the quarterly scan process to show that all systems were scanned and all applicable vulnerabilities have been addressed. Additional documentation may be required to verify non-remediated vulnerabilities are in the process of being addressed.
For initial PCI DSS compliance, it is not required that four quarters of passing scans be completed if the assessor verifies

  1. the most recent scan result was a passing scan,
  2. the entity has documented policies
    and procedures requiring quarterly scanning, and
  3. vulnerabilities noted in the scan results have been corrected as shown in a re-scan(s).

For subsequent years after the initial PCI DSS review, four quarters of passing scans must have occurred.

11.2 Examine scan reports and supporting documentation to verify that internal and external vulnerability scans are performed as follows: (See 11.2.#)

A vulnerability scan is an automated tool run against external and internal network devices and servers, designed to expose potential vulnerabilities that could be found and exploited by malicious individuals.
There are three types of vulnerability scanning required for PCI DSS:
• Internal quarterly vulnerability scanning by qualified personnel (use of a PCI SSC Approved Scanning Vendor (ASV) is not required)
• External quarterly vulnerability scanning, which must be performed by an ASV
• Internal and external scanning as needed after significant changes
Once these weaknesses are identified, the entity corrects them and repeats the scan until all vulnerabilities have been corrected.
Identifying and addressing vulnerabilities in a timely manner reduces the likelihood of a vulnerability being exploited and potential compromise of a system component or cardholder data.