Which of the following is NOT considered a cyber security threat?

Spam mail, while often seen as an inconvenience or nuisance, is not inherently classified as a cyber security threat in the same way as the other options. Spam refers to unsolicited messages typically sent in bulk, primarily for advertising purposes. While it can be used as a vehicle for delivering threats, such as phishing attacks or malicious links, not all spam is malicious in nature or designed to compromise a system.

In contrast, social engineering involves manipulating individuals into divulging confidential information, malicious code refers to software specifically designed to disrupt or damage systems, and insider threats pertain to individuals within an organization misusing their access to data or systems for malicious purposes. Each of these options poses direct risks that can lead to significant breaches of security, making them clearly categorized threats in cyber security. Spam mail, therefore, stands apart as it does not necessarily aim to exploit vulnerabilities or compromise data security directly.