Board Changes

20 March 2012

Corero Network Security plc

("Corero" or the "Company")

Board changes

Corero Network Security plc (AIM: CNS), the network security and business software provider, is pleased to announce that Stephen Graham, a General Partner of CrossHill Georgetown Capital LP and CrossHill Debt II LP (together "CrossHill"), has joined the board of directors of the Company as non-executive director.

Mr Graham's appointment is a result of CrossHill, which became a significant shareholder in the Company following the acquisition of Top Layer Networks, Inc., exercising its right to appoint a non-executive director, as disclosed in the admission document of the Company dated 7 February 2011. At the same time, Edward Forwood, a director of Loudwater Trust Limited ("Loudwater") has resigned as a director of the Company following the disposal of Loudwater's shareholding in the Company, as announced on 17 February 2012.

Disclosures required pursuant to Schedule 2(g) of the AIM Rules for Companies in respect of Mr Graham are set out below.

Following the above changes, the Board of Directors of the Company will comprise Jens Montanana, (non-executive Chairman), Richard Last (non-executive director), Stephen Graham (non-executive director) and Andrew Miller (COO and executive director).

Enquiries:

About Corero Network Security plc

Corero Network Security plc consists of two businesses: Corero Network Security and Corero Business Systems.

Corero Network Security is an international network security company and the leading provider of Distributed Denial of Service (DDoS) defence and Intrusion Prevention System (IPS) solutions. Corero's products and services provide comprehensive, integrated, high-performance protection against constantly evolving network-borne cyber threats. Customers include enterprises, service providers and government organisations worldwide. Corero's appliance-based solutions are highly adaptive and preemptively respond to modern cyber attacks, known and unknown, protecting critical information and online assets. Corero's products have superior performance, are highly scalable, and feature the lowest latency and best reliability in the industry.

Corero Business Systems is a leading provider of powerful and dynamic modular accounting, human resources, payroll and management information software to the schools (including academies) and further education sectors in the UK and internationally.

Disclosures required pursuant to Schedule 2(g) of the AIM rules for companies

Name: Stephen Xavier Graham (Age 59)

Mr Graham currently holds, and has during the last five years immediately preceding the date of this announcement held, the following directorships or partnerships:

There are no other matters which are required to be announced under Schedule 2(g) of the AIM Rules.