Reaction Information Security

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Network penetration testing, web application security, firewall review, CHECK pen testing, server build review, social engineering..


CHECK Team Leader

A CHECK Team Leader is an IT security consultant qualified to lead penetration testing engagements on classified government networks and systems under the CESG IT health CHECK scheme. The CHECK Team Leader must have passed one of the qualifying technical assault courses to demonstrate significant breadth and depth of knowledge in the field of penetration testing before gaining the status.

All our CHECK consultancy projects are lead by Joseph Sheridan, founder and Lead Consultant at ReactionIS. Joseph has been a qualified CHECK Team Leader (in both infrastructure and web applications) since 2008.

CHECK Team Leaders - Qualification

CHECK Team Leaders typically have 5 years' practical experience in a full time testing role before they are able to pass one of the technical assault courses run by CREST or TigerScheme. In the case of CREST, the candidate can either pass the CREST Certified Infrastructure Tester or the CREST Certified Web Applications Tester exams to satisfy the technical requirements for CHECK Team Leader status. In addition to the technical requirements, the tester must be employed full time by a CHECK green light company and have valid SC clearance (or be able to obtain clearance).

A CHECK Team Leader is able to be the sole consultant on a CHECK penetration test. However, on larger engagements, he/she can be assisted by one or more CHECK Team Members who are usually more junior testers but have passed the CREST Registered Tester exam and are security cleared.

ReactionIS are a CHECK green light company, please get in touch for more details.


CHECK Team Leader, joseph sheridan

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Penetration Testing Services

Firewall reviews, database audits, code reviews, social engineering and more..

Application Security

Ensure your web and mobile apps are safe from attack.

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