What Security Lessons Did We Learn in 2024?

From the growing sophistication of zero-day exploits to the entrenchment of nation-state and cybercriminal alliances, 2024 delivered more evidence of how quickly the threat landscape continues to evolve. The year reinforced hard truths about the persistence of attackers and the systemic challenges of defense. We look back on some of the events that defined 2024 and the tactical insights that security teams can apply to stay ahead in the ongoing battle in 2025.

Surging Zero-Day Exploits and Nation-State Collaboration

Threat researchers continued to see a year-over-year increase of zero days. Recent analysis by Mandiant of 138 vulnerabilities that were disclosed in 2023 found the majority (97) were exploited as zero-days — an increase from 2022. Tom Kellermann, senior vice president of cyber strategy at Contrast Security, expects that number to increase in 2024.

The growth is a direct result of geopolitical tensions, he says. Nation-state actors, particularly China, are exploiting these types of vulnerabilities at unprecedented rates.

"The Chinese specifically have been doing tremendous research into exploiting zero-days and discovering them," Kellermann says. "I think everyone's kind of on their back foot when dealing with this because traditional cybersecurity defenses can't thwart those attacks."

The rise in these kinds of attacks includes a new trend in 2024: collaboration or coordination between nation-states and cybercrime rings, says Stephan Jou, senior director of security analytics at OpenText Cybersecurity.

"In this model, an attack with nation-state characteristics is launched at the same time, or followed closely by, an attack on the same target by an independent for-profit threat actor. Russia, for example, has been seen to collaborate with malware-as-a-service gangs, including Killnet, LokiBot, Gumblar, Pony Loader, and Amadey. China has entered similar relationships with the Storm-0558 and Red Relay cybercrime rings, typically to support its geopolitical agenda in the South China Sea."

Chester Wisniewski, global field CTO at Sophos, says China-sponsored attackers have developed assembly-line zero-day exploits shared through state-mandated disclosure laws. Attackers initially used zero-days in targeted attacks, then escalated them to widespread exploitation to cover their tracks. Proactive patch management and collaboration between vendors and organizations to mitigate threats is critical, he says.

"The real problem is this accumulation of stuff that's not getting patched," Wisniewski says. "We just keep launching more equipment out there onto the Internet. And it's getting more and more polluted, and nobody's responsible for taking care of it."

Jou agrees and says the lesson here is that defense against even sophisticated attacks comes back to the same basics: patch management, endpoint protection, email security, awareness training, and backup and disaster recovery planning.

"By ensuring that these unglamorous but essential best practices are in place, security teams can rob threat actors of many of their favorite tactics to abuse networks and businesses," he says.

Resiliency Planning Needs More Focus

Ransomware attacks in 2024 highlighted the fragility of supply chains and business continuity. Ransomware operators are now targeting service providers and supply chain networks, Wisniewski says. A cyberattack on Ahold Delhaize, the parent company of major US supermarket chains, including Stop & Shop, Hannaford, Food Lion, and Giant Food, disrupted services across its network in November, impacting more than 2,000 stores. For several days, customers had issues with online grocery delivery, offline websites, and limited pharmacy services.

Improving business continuity strategies to include modern segmentation tools can help minimize operational disruptions during incidents, Wisniewski says.

"When one part of a supply chain goes down, it impacts thousands of businesses," he says. "This amplifies the economic and operational pressure to comply with attackers' demands. You can't plan never to fail, but you can plan to fail gracefully."

Another headline-making business continuity incident this year was the CrowdStrike outage. In July, the company released a faulty software update that affected approximately 8.5 million devices running the Windows operating system. The glitch triggered widespread system crashes that resulted in multiple disruptions, particularly in the travel industry. Delta Air Lines was forced to cancel thousands of flights due to system disruptions. 

The event dominated news cycles for several days. In its wake, analysts pointed to the critical need for better process adherence and visibility. But Dror Liwer, cofounder of Coro, says it also highlights a need for security leaders to  effectively communicate with diverse stakeholders — whether technical teams, business executives, or external parties — when managing the fallout of a large-scale incident.

Critical Infrastructure Is a Growing Target

Attacks on critical infrastructure reached new levels in 2024. In September, the Cybersecurity and Infrastructure Security Agency (CISA) issued a notice that government-run water systems were at risk of attack by nation-states after officials reported a cybersecurity issue at a facility in Arkansas City, Kansas, which was forced to switch to manual operations while the situation was resolved.

Barry Mainz, CEO of Forescout, says cyberattacks are evolving to target critical services, like municipal water authorities and airport landing systems. This year made it clear that attackers are shifting their focus from well-protected facilities to more vulnerable upstream systems, like water supplies and power grids, he says.

"If you just zoom out a bit and look at where the vulnerabilities are, the bad actors are saying, 'Well, it's a lot harder now since people are spending money to secure certain IT functions. We're going to go down the food chain a little bit,'" Mainz says.

One of the key challenges in securing critical infrastructure is the inherent complexity of operational environments. Many industrial systems operate using legacy equipment that was never designed with cybersecurity in mind. In addition, there is often a lack of visibility into connected devices within these environments, which can make detecting threats extremely difficult.

"I think the lesson is we've got to invest in a cybersecurity strategy for not only IT systems but [operational technology] systems," Mainz says. "And also we need to think structurally about how we manage those systems because the people that actually manage those OT systems, they're not IT professionals.”

A better approach, he says, involves adopting advanced monitoring and threat detection tools as well as fostering collaboration between IT and OT teams. By breaking down silos and improving communication, organizations can better address the unique security requirements of critical infrastructure. Mainz pointed to the importance of government and private-sector partnerships in bolstering defenses.

Telecom Can't Be Trusted

We wrap up 2024 with news that Salt Typhoon, a cyber-espionage group allegedly linked to the Chinese government, has successfully infiltrated telecommunications networks in multiple countries. In the US alone, FBI officials say at least eight major telecom companies, including AT&T, Verizon, and Lumen Technologies, were compromised. The group gained access to sensitive data, such as call logs, unencrypted text messages, and, in some cases, live call audio. The FBI recommended that Americans use encrypted messaging apps, like Signal and WhatsApp, to ensure their communications stay hidden.

The ongoing issues around nation-state attackers and their use of telecom is one of his biggest worries heading into 2025, Kellermann says. He also points to T-Mobile's acquisition of Sprint in 2020, which he says is concerning because "Sprint used to be the classified backbone network of the US government." This means that if there are security vulnerabilities within T-Mobile's infrastructure, they could potentially compromise sensitive government communications or systems that were part of Sprint's legacy network. 

"I think the people are ignoring that and are not paying attention fully," he says.