5 of the most common cyberattacks, from 'injection' to 'brute force' hacks — and how they've been used in past conflicts

As Russia escalates its ground invasion of Ukraine, it may also employ massive and debilitating cyberattacks on the country and its allies.

• Russia is one of the world's most sophisticated cyber-aggressors. 
• While it hasn't employed massive cyberattacks against Ukraine yet, it could soon. 
• There are five common types of cyberattacks, all of which have been used in past conflicts.

As Russia escalates its ground invasion of Ukraine, it could soon employ massive cyberattacks that could debilitate governments, infrastructure, and everyday citizens. 

Cyberwarfare is one of Russia's go-to methods of wreaking havoc, earning it a reputation as one of the world's most sophisticated cyber-aggressors. In fact, about two-thirds of state-sponsored cyberattacks have been linked to Russia in recent years, according to new research on the economic impacts of cyberattacks compiled by Goldman Sachs analysts led by Ronnie Walker.

According to the note, published Monday, there are five common types of attacks, all of which have been used on the world stage to disrupt governments, steal data, and cause chaos: 

• Denial-of-service (DoS). In a denial-of-service attack, hackers will flood a server with traffic in an attempt to crash it and make it inaccessible to users. In 2021, hackers targeted the Belgian government's internet service provider in a massive DoS attack.
• Malware. Malware, or malicious software, is designed to steal data or disrupt or destroy a network. In January, North Korea-linked hackers targeted Russian diplomats with malware delivered in the form of New Year's greeting emails.
• Injection. An injection attack allows hackers to insert code into a program that will allow it to execute commands remotely. This happened in 2017, when a suspected Russian hacker manipulated the programming language SQL — a practice known as SQL injections — to compromise more than 60 US universities and government organizations.
• Phishing. Phishing attacks involve sending seemingly trustworthy emails in order to trick a source and extract data from them. North Korea-linked operatives have used targeted phishing attacks, known as spear-phishing, to steal information from employees at US defense contractors, energy firms, tech companies, and aerospace companies.
• Brute force. Hackers who rely on brute force use trial and error to guess a user's credentials in order to break into their network. In 2017, suspected Iranian hackers attempted to guess the password of 9,000 UK Parliament accounts. The attackers were able to successfully compromise as many as 30 accounts. 

Russian-linked hackers have aggressively targeted Ukraine over the years

In 2016, suspected Russian hackers took down Ukraine's power grid, causing a blackout for hundreds of thousands of Ukrainians. Ukraine was also on the receiving end of another damaging cyberattack in 2017 that wiped data from banks, government computers, and energy firms.

The attack, known as NotPetya, was conducted by Russian hackers, the CIA said, and resulted in more than $10 billion in damages, according to Goldman Sachs. 

And in the hours before Russia invaded Ukraine, Microsoft detected a never-before-seen piece of malware designed to wipe data from the networks of Ukraine's government and banks. The tech giant blocked the code within hours, The New York Times reported.  

But while experts have long predicted that a war between Russia and Ukraine would consist of crippling cyberattacks on Ukraine's infrastructure, so far, that hasn't quite come to pass. 

"We imagined this orchestrated unleashing of violence in cyberspace, this ballet of attacks striking Ukraine in waves, and instead of that we have a brawl. And not even a very consequential brawl, just yet," Jason Healey, a Columbia University research scholar specializing in cyber conflict, told the Washington Post. 

Still, cyberattacks are increasingly likely to become a phase of the war in Ukraine, and experts warn that it won't be confined to Ukraine's borders.

"Given that the US and EU have banded together in support of Ukraine, the scope of a cyberwar could be broad," Stuart Madnick, a professor at MIT Sloan School of Management, wrote in Harvard Business Review on Monday. "Large scale cyber skirmishes can become global due to a spillover effect."