Nigeria, Kenya and South Africa were ranked in the top 100 for global online cyber threats, Kaspersky data revealed.
The report said that Kenya at present ranked top among African countries and 35th worldwide for online threats.
Nigeria is Africa's second most vulnerable African nation for online hacks and ranks 50th globally.
In third place is South Africa, which is 82nd globally according to the research conducted by Kaspersky.
The same type of attempted attacks were reported in Nigeria, with 46,000 cases, and in Kenya the number of such attacks rose to 143,000. However, in Kenya, "exploits" [scripts that use vulnerabilities in systems to execute commands] were the most common form of attack, with 177,000 incidents blocked.
Kaspersky also noted an outbreak of zombie machines - connected devices that become part of a botnet. These include outdated, old and forgotten devices, printers, cameras and even coffee makers. In the past year, 1.6 million zombie machines have been discovered in South Africa and 300,000 in Kenya.
According to Amin Hasbini, head of Kaspersky's Global Research and Analysis Team, "criminal attacks are mainly driven by the pursuit of financial profit".
Hasbini noted that there is no universal solution to the problem of securing a network. However, "cyber security measures are an ongoing endeavor".
"Businesses should consider leveraging advanced technologies such as threat feeds, security information and event management systems, endpoint detection and response solutions, and tools with digital forensics and incident response features," the expert pointed out.
According to the Kaspersky report on its website, the most vulnerable countries in the world for the threat of Internet attacks are Haiti, the Republic of Korea, and China.