Network Penetration Testing Providers
Network penetration testing evaluates the security of your organisation's network infrastructure by simulating attacks against internal and external network assets. External network pen testing targets internet-facing systems including firewalls, VPN gateways, mail servers, DNS servers, and web servers to identify vulnerabilities that could allow an attacker to gain initial access.
Internal network pen testing simulates an attacker who has already gained a foothold inside the network, testing for lateral movement opportunities, privilege escalation paths, misconfigured services, weak credentials, and unpatched systems. Testers use tools and techniques similar to those used by real adversaries, including port scanning, service enumeration, vulnerability exploitation, and credential attacks.
Network pen testing is critical for organisations of all sizes and is required by compliance frameworks including PCI DSS, NIST CSF, ISO 27001, and Cyber Essentials. Regular testing helps organisations understand their actual security posture and prioritise remediation efforts based on real risk.
SECFORCE
Leading UK offensive security consultancy based in Canary Wharf, delivering CREST-accredited penetration testing and adversary simulation to organisations with the most demanding security requirements.
NCC Group
Global cybersecurity consultancy with CREST, CHECK, and CBEST accreditation, renowned for deep technical research and comprehensive penetration testing services.
Nettitude
CREST, CHECK, and CBEST accredited UK consultancy within Lloyd's Register, delivering premium penetration testing for government and critical infrastructure.
NetSPI
Leading penetration testing firm with the Resolve platform for continuous attack surface management, trusted by nine of the top ten US banks.
Pen Test Partners
The UK's largest independent security testing firm, renowned for IoT/OT research, CBEST red teaming, and CHECK/CREST-accredited penetration testing across all sectors.
PwC Cyber Security
Global Big Four professional services firm delivering CREST, CHECK, and CBEST-accredited penetration testing and red teaming services from London, serving the UK's largest enterprises and regulated organisations.
Dionach
Global enterprise cybersecurity consultancy founded in 1999 in Oxford, holding rare CREST STAR-FS accreditation and delivering penetration testing, red and purple teaming, and PCI QSA services across five international offices.
MDSec
Elite UK offensive security consultancy specialising in CBEST/STAR/TIBER red teaming, advanced adversary simulation, and CREST-accredited penetration testing for FTSE 100 clients.
Trustwave
Global managed security provider with the elite SpiderLabs penetration testing team and deep PCI DSS compliance expertise.
Secarma
Manchester-based independent cybersecurity consultancy with over 20 years of experience delivering CREST and CHECK-accredited penetration testing, red teaming, and compliance certification services.
Cyberis
CREST and CHECK-accredited UK penetration testing consultancy with CBEST approval, specialising in infrastructure, application, and simulated attack assessments across the public and private sectors.
Aristi
CHECK and CREST-accredited Birmingham-based cyber security consultancy with over 15 years of experience delivering penetration testing, red teaming, and OT security assessments for government and private sector clients.
Network Penetration Testing FAQs
What is the difference between external and internal network pen testing?+
External testing targets internet-facing systems to find ways an attacker could breach the perimeter. Internal testing simulates an attacker already inside the network, testing for lateral movement and privilege escalation.
Will network pen testing cause downtime?+
Professional penetration testers take precautions to avoid service disruption. Testing is typically scheduled during agreed windows and testers avoid denial-of-service attacks unless specifically requested and authorised.
What do I need to provide for a network pen test?+
For external testing, provide IP ranges and domains in scope. For internal testing, provide network access (VPN or on-site), IP ranges, and any systems to exclude. Clear scoping and rules of engagement should be agreed in advance.