A security system for preventing cyberattacks in a system comprising a plurality of computer devices (41, 42, 43, 44), the security system comprising: - at least one control device (11, 12, 13) comprising: - means for authenticating a user trying to physically access a zone comprising at least one computer device of said plurality of computer devices (41, 42, 43, 44); - means for authenticating a data storage device said user intends to insert in at least one of those computer devices (41, 42, 43, 44) and for verifying, cleaning and encrypting the content of said data storage device; - means for, if the data storage device carried by said user is a private data storage device, providing a corporate data storage device, wherein said provided corporate data storage device comprises a copy of the verified, cleaned and encrypted content originally stored in said private data storage device; - a software agent installed in at least one of said plurality of computer devices (41, 42), said software agent being configured: for detecting if a data storage device inserted into a port of said computer device (41, 42) is a private one or a corporate one; for, in the event of a private one, denying the data storage device access to that computer device (41, 42); and for, in the event of a corporate one, checking if its content has been verified, cleaned and encrypted by a control device (11, 12, 13) and, in the event it has, decrypting the content of said corporate data storage device, thus permitting said computer device (41, 42) to read or run said content. - at least one control device (11, 12, 13) comprising: - means for authenticating a user trying to physically access a zone comprising at least one computer device of said plurality of computer devices (41, 42, 43, 44); - means for authenticating a data storage device said user intends to insert in at least one of those computer devices (41, 42, 43, 44) and for verifying, cleaning and encrypting the content of said data storage device; - means for, if the data storage device carried by said user is a private data storage device, providing a corporate data storage device, wherein said provided corporate data storage device comprises a copy of the verified, cleaned and encrypted content originally stored in said private data storage device; - means for authenticating a user trying to physically access a zone comprising at least one computer device of said plurality of computer devices (41, 42, 43, 44); - means for authenticating a data storage device said user intends to insert in at least one of those computer devices (41, 42, 43, 44) and for verifying, cleaning and encrypting the content of said data storage device; - means for, if the data storage device carried by said user is a private data storage device, providing a corporate data storage device, wherein said provided corporate data storage device comprises a copy of the verified, cleaned and encrypted content originally stored in said private data storage device; - a software agent installed in at least one of said plurality of computer devices (41, 42), said software agent being configured: for detecting if a data storage device inserted into a port of said computer device (41, 42) is a private one or a corporate one; for, in the event of a private one, denying the data storage device access to that computer device (41, 42); and for, in the event of a corporate one, checking if its content has been verified, cleaned and encrypted by a control device (11, 12, 13) and, in the event it has, decrypting the content of said corporate data storage device, thus permitting said computer device (41, 42) to read or run said content.