Every organization tries to achieve CIA $($confidentiality$,$ integrity, and availability$).$ Here is the summary of an attack happened in $2020.$ What kind of attack is this?

Twitter saw one of the most brazen online attacks to date when on July $15,2020,$ hackers verified Twitter accounts of many high$-$profile figures and celebrities, everyone from Kim Kardashian and Kanye West to Barack Obama, Elon Musk, and Bill Gates. The successful attack targeted a small number of employees though a phone spear phishing campaign, granting hackers access to Twitter$$s internal support system which then enabled them to target additional employees. According to Twitter, using the acquired credentials, $130$ Twitter accounts were targeted, with the hackers Tweeting from $45,$ accessing the direct messaging inbox of $36$ and downloading the Twitter Data of $7.$ Twitter Support released a statement saying, $$This attack relied on a significant and concerted attempt to mislead certain employees and exploit human vulnerabilities to gain access to our internal systems.$$ The true outcome of this enormous hack has yet to be seen, but the incident has led to major distrust with Twitter and its security measures, and will most likely live on as one of the worst cybersecurity disasters to a social media platform.

Group of answer choices

It is an attack on Confidentiality

It is an attack on Confidentiality and Integrity

It is a denial of service attack

It is a spear phishing attack