An IT service company's primary function is to provide businesses with crucial technological solutions. This ranges from vulnerability testing to cyber security services, and even to supplying and managing cloud computing services.

One of the key offerings from IT service companies is the vulnerability testing service. This service probes a business's system for vulnerabilities that would allow external threats to breach the defenses. Using a combination of automated and manual techniques, these tests try to identify flaws in the system as a preemptive measure for security enforcement.

Transitioning into the realm of cyber security services, IT companies guarantee the protection of business applications, databases, and networks against heterogeneous cyber threats. They provide holistic security measures, including anti-malware and antivirus defences, intrusion detection systems, firewalls, and crisis response plans. IT service companies exert themselves to stay up to date with evolving cyber threat landscapes, ensuring their client's business's digital properties are well protected.

We now shift our attention to another significant service - cloud computing. Cloud computing services essentially allow businesses to store and control their data over the internet instead of an on-premises server. This is advantageous as it provides improved flexibility, cost efficiency, more collaboration and endless scalability. As providers of cloud services, IT companies handle the job of managing this off-site data storage system, providing premium availability and security for a business's valuable data.

In wrapping up, it is evident that the role of an IT service company is multifaceted, offering a wide array of services including but vulnerability testing service not limited to vulnerability testing, cyber security, and cloud computing services. These services play a critical role in maintaining the security and efficiency of a business's digital infrastructure. By partnering with a reliable IT service company, one can ensure that their business remains protected and efficient in an increasingly digital world.