External Penetration Testing

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External Penetration Testing

External Penetration Testing Overview

A penetration test of your external-facing network services identifies vulnerabilities that may be exploited by an attacker.


Ensuring your network perimeter is resilient to Internet-based threats is your first line of defence against both attackers and malware, that may target the network services that your organisation exposes on the Internet.

Vulnerabilities in your Internet-facing network services can present a significant risk to your organisation, if they can be compromised by a malicious user, who may then attempt to pivot an attack onto your internal network.

Some of the more common vulnerabilities found on Internet-facing services include outdated operating systems and software, legacy encryption protocols, misconfigured VPN gateways, web servers and mail servers and administrative services being exposed to the Internet.

A penetration test against your Internet-facing network services helps you identify the vulnerabilities that may be exploited by an Internet-based attacker. Using the same techniques that would be used in a real-life cyber-attack, our penetration testing team evaluates the level of access that can be obtained to your environment from the Internet.


Using a combination of automated and manual testing, our consultants will inspect your Internet-exposed services to assess if vulnerabilities are present that could allow them to be exploited by a malicious user.

Our external penetration testing comprises the following stages, which are representative of a real-life attack:

  1. Passive Reconnaissance
  2. Network Enumeration
  3. Active Testing

Passive Reconnaissance

During the initial stages of a real-life attack, malicious users will spend time performing reconnaissance, so that a profile or ‘footprint’ of the target organisation can be obtained. Information such as the IP addresses in use, hostnames and employee information, can greatly assist an attacker in choosing an effective attack method and may help identify areas of the target organisation’s infrastructure that would render the highest impact if compromised.

Public databases and information services can contain a wealth of information that may prove useful to an attacker. Most of these information sources can be freely and passively accessed and with these information sources residing in the public domain, there is no chance that the searches performed by an attacker will trigger alerts that may notify the target organisation that an attack is being planned.

During this phase of the testing, the following public information sources will be accessed to obtain further information about the target organisation:

  1. RIPE Database
  2. WHOIS Database
  3. Domain Name Servers

Network Enumeration

Once an attacker has built a profile of the organisation through passive information gathering, they will attempt to identify ‘live’ hosts and services within the IP address range. Once an understanding of the exposed ports and services is obtained, this will give the attacker more information on potential vulnerabilities that may allow them to gain a foothold on the network and further their attack.

During this phase of the test, a full TCP and UDP port scan of all 65,535 ports will be conducted over the in-scope IP range. An ICMP scan will also be conducted, to identify which hosts would disclose their presence to an attacker who performs a simple ‘ping’ scan.

Active Testing

Based on the results of the Network Enumeration phase, a vulnerability assessment and targeted penetration test will be conducted on all Internet-exposed services. All results of the vulnerability assessment will be manually verified to ensure that no ‘false positive’ results are present.

All exposed services will be manually inspected by connecting to them and attempting to gain access through known exploits.


  1. A signed & completed Testing Consent Form
  2. List of IP addresses or hostnames to be assessed