Все просто, ИБ - это защита информации в любом виде (цифровые данные, бумажные документы, аудио и пр.), а кибербезопасность - защита только цифровых данных.
ISACA:
"The terms “cybersecurity” and “information security” are often used interchangeably. Some use the term cybersecurity as a synonym for information security, IT security and information risk management. Others, particularly in government circles, have adopted more technical definitions related to national defense, including cyber warfare and protection of critical infrastructure. Although different groups tend to adapt terminology for their own purposes, there are some important distinctions between cybersecurity and information security.
Information security deals with information, regardless of its format—it encompasses paper documents, digital and intellectual property in people's minds, and verbal or visual communications. Cybersecurity, on the other hand, is concerned with protecting digital assets—everything from networks to hardware and information that is processed, stored or transported by internetworked information systems. Additionally, concepts such as nation-state-sponsored attacks and advanced persistent threats (APTs) belong almost exclusively to cybersecurity. It is helpful to think of cybersecurity as a component of information security."
