1. Introduction

Vulnerability management is a core element in modern information technology (IT) compliance. IT compliance is defined as the adherence to legal, corporate and contractual rules and regulations related to IT infrastructures. Within its context IT compliance mainly relates to information security, availability, storage and privacy. Companies and agencies have to comply with many legal obligations in this area.

Controlling and improving IT security is an ongoing process consisting of at least the following steps:

  • Discovery of the current state
  • Improving the current state
  • Reviewing the taken measures

The Greenbone Security Manager (GSM) assists companies and agencies with automated and integrated vulnerability assessment and management. Its task is to discover vulnerabilities and security gaps before a potential attacker does.

The GSM achieves this through different perspectives of an attacker:

External
The GSM can attack the network externally to identify outdated or misconfigured firewalls.
Demilitarized Zone (DMZ)
The GSM can identify actual vulnerabilities that may be exploited by attackers that get past the firewall.
Internal
The GSM can also identify exploitable vulnerabilities in the internal network, for example those targeted by social engineering or computer worms. Due to the potential impact of such attacks, this perspective is particularly important for the security of any IT infrastructure.

For DMZ and internal scans, a distinction can be made between authenticated and unauthenticated scans. When performing an authenticated scan, the GSM uses credentials and can discover vulnerabilities in applications that are not running as a service but have a high risk potential. This includes web browsers, office applications or PDF viewers. For the advantages and disadvantages of authenticated scans see Chapter 10.3.1.

Due to new vulnerabilities being discovered on a daily basis, regular updates and testing of systems are required. The Greenbone Security Feed ensures that the GSM is provided with the latest testing routines and can discover the latest vulnerabilities reliably. Greenbone Networks analyzes CVE 1 messages and security bulletins of vendors and develops new vulnerability tests daily.

When performing a vulnerability scan using the GSM, the personnel responsible will receive a list of vulnerabilities that have been identified in the target systems. For the selection of remediation measures a prioritization is required. The most important measures are those that protect the system against critical risks and eliminate the corresponding security holes.

The GSM utilizes the Common Vulnerability Scoring System (CVSS). CVSS is an industry standard for the classification and rating of vulnerabilities. It assists in prioritizing the remediation measures.

Fundamentally, there are two options to deal with vulnerabilities:

  • Eliminating the vulnerability by updating the software, removing the component or changing the configuration.

  • Implementing a rule in a firewall or a intrusion prevention system (virtual patching).

    Virtual patching is the apparent elimination of the vulnerability through a compensating control. The real vulnerability still exists and the attacker can still exploit the vulnerability if the compensating control fails or if an alternate approach is used.

An actual patch or update of the affected software is always preferred over virtual patching.

The GSM also supports the testing of the implemented remediation measures. With its help responsible personnel can document the current state of IT security, recognize changes and record these changes in reports.

Footnotes

[1]The Common Vulnerability and Exposures (CVE) project is a vendor neutral forum for the identification and publication of new vulnerabilities.