External network penetration testing for Australian organisations
Your internet-facing infrastructure is the first thing an attacker sees. External network penetration testing determines whether your public-facing systems can withstand a targeted attack from outside your network perimeter.
dotSec’s external penetration tests go beyond automated scanning. Our assessors combine vulnerability discovery tools with manual exploitation techniques to identify weaknesses that scanners alone will miss, including chained attack paths, misconfigured cloud services, and exposed APIs. Every finding is validated, assessed for real-world exploitability, and reported with prioritised remediation guidance.
What is external network penetration testing?
An external network penetration test is a controlled security assessment in which an assessor operates from the internet and attempts to identify and exploit vulnerabilities in your organisation’s publicly accessible systems. The assessor works without internal network access or credentials (unless a grey-box approach is agreed), simulating the perspective of an external attacker targeting your perimeter.
The scope of an external test typically includes any system reachable from the internet. In a contemporary environment, that extends well beyond traditional firewalls and mail servers. dotSec’s external assessments cover:
- Public-facing web applications and customer portals
- REST and GraphQL APIs exposed to the internet
- Email infrastructure, including SPF, DKIM and DMARC configuration
- Remote access services such as VPN gateways and RDP endpoints
- Cloud service endpoints, including AWS S3 buckets, Azure Blob storage and exposed management consoles
- DNS infrastructure, including zone transfer controls and subdomain enumeration
- TLS configuration and certificate management
- Externally exposed administrative interfaces and development or staging environments
An external pen test differs from a vulnerability scan in a fundamental way. A vulnerability scan identifies the potential presence of known weaknesses. A penetration test goes further: the assessor manually validates each finding, attempts exploitation, chains individually low-risk issues into higher-impact attack paths, and assesses the real business impact of a successful compromise. NIST SP 800-115 describes this distinction, and NIST SP 800-53 Rev. 5 control CA-8 defines penetration testing as a required security control activity for federal systems.
What dotSec tests during an external network penetration test
dotSec does not run a single scanning tool and hand over the output. Each external engagement is scoped to your specific environment and includes manual testing across the following areas.
Network services and infrastructure
We identify open ports, running services and their versions across your external IP ranges. Testing includes assessment of service configurations, default credentials, known vulnerabilities in exposed software, and network-level misconfigurations such as permissive firewall rules or unnecessary services exposed to the internet.
Web applications and APIs
Publicly accessible web applications and APIs are tested for vulnerabilities consistent with the OWASP Web Security Testing Guide, including injection flaws, broken authentication, insecure direct object references, and business logic errors. API testing covers both REST and GraphQL endpoints, with attention to authentication mechanisms, rate limiting, data exposure and input validation.
Cloud services
Where your external footprint includes cloud-hosted resources, we assess configuration weaknesses that could allow unauthorised access. This includes publicly accessible storage (S3 buckets, Azure Blob containers), overly permissive IAM policies on internet-facing services, and exposed cloud management interfaces. Testing is conducted within the shared responsibility boundaries of the relevant cloud provider (AWS, Azure or GCP).
Email and DNS security
We assess your email infrastructure for spoofing resilience (SPF, DKIM, DMARC configuration), open relay conditions, and information disclosure through mail server banners. DNS testing covers zone transfer controls, subdomain enumeration, and DNSSEC implementation where applicable.
Remote access and VPN endpoints
VPN gateways, remote desktop services and other remote access infrastructure are tested for known vulnerabilities, weak authentication, and configuration weaknesses that could provide an attacker with a foothold into your internal network.
Why external network penetration testing matters
Your external perimeter is the most exposed part of your infrastructure. It is continuously scanned by automated tools, targeted by opportunistic attackers, and probed by more sophisticated adversaries conducting reconnaissance for targeted campaigns.
External penetration testing addresses this exposure directly. It identifies the specific weaknesses in your internet-facing systems that an attacker could exploit to gain initial access, exfiltrate data, or disrupt services. Beyond identifying individual vulnerabilities, it reveals how those weaknesses combine to create exploitable attack paths.
Several compliance frameworks require or strongly recommend regular external penetration testing. PCI DSS v4.0.1 Requirement 11.4 mandates penetration testing of the external network perimeter at least annually and after significant changes. APRA CPS 234 requires APRA-regulated entities to test the effectiveness of information security controls, and external pen testing is a primary method of doing so. The ACSC Essential Eight maturity model, while not prescribing penetration testing directly, is informed by ASD’s penetration testing experience, and external testing provides evidence relevant to patching and configuration controls. ISO 27001:2022 Annex A.8.8 addresses technical vulnerability management, for which external testing provides objective evidence.
For organisations that operate a managed SOC or SIEM, external pen test findings also provide valuable context for detection rule tuning and alert prioritisation.
External network penetration testing FAQ
What is the difference between external and internal penetration testing?
External testing targets systems accessible from the internet, simulating an attacker with no internal network access. Internal testing operates from inside the network perimeter, simulating an attacker who has already gained a foothold, for example through a phishing attack or compromised credentials. External testing answers the question “can someone break in from the outside?”, while internal testing answers “how far can they go once inside?”. Most organisations benefit from both, and dotSec can scope a combined engagement that covers both perspectives.
How long does an external penetration test take?
Duration depends on the size of the external attack surface. A small engagement covering a handful of public IPs and a web application may take several days. A larger scope covering multiple network ranges, cloud environments and several web applications can take two to three weeks. Timelines are agreed during the scoping phase, and dotSec coordinates scheduling with your operations team to avoid disruption.
Does external penetration testing include cloud services?
Yes, where cloud-hosted services form part of your external footprint. dotSec tests for publicly accessible storage, misconfigured IAM policies on internet-facing resources, exposed management consoles, and other cloud-specific weaknesses across AWS, Azure and GCP. Testing is conducted within the shared responsibility boundaries of each cloud provider, and any provider-specific authorisation requirements are handled during scoping.
How often should we conduct external penetration testing?
At a minimum, annually and after any significant infrastructure change (such as a major application deployment, cloud migration, or network redesign). PCI DSS requires annual testing plus testing after significant changes. Organisations with higher risk profiles or rapidly changing environments may benefit from more frequent testing or continuous vulnerability scanning between pen test engagements.
What next?
If your organisation needs an external penetration test, whether for compliance, risk management, or as part of a broader security improvement programme, dotSec can scope an engagement to match your requirements.
External pen test findings can feed directly into remediation programmes across secure configuration and hardening, identity and access management, and SOC and SIEM detection tuning. For organisations with governance and compliance requirements, dotSec’s GRC specialists can help align findings with your risk register and provide audit-ready evidence.
Premier australian cyber security specialists
