“Human Behavior Is the Weakest Link”: CertiK Co-Founder on the Real Threat in Crypto

• CertiK co-founder says human behavior, not flawed code, is the biggest security risk in crypto.
• Hackers stole nearly $2.5 billion in the first half of 2025, with $1.7B from wallet compromises.
• Ethereum was the most targeted ecosystem, accounting for $1.6 billion of the total funds stolen.

The biggest weak point hackers exploited in the first half of 2025 wasn’t the code—it was human behavior, according to CertiK co-founder Ronghui Gu. Gu made the statement during an interactive session on X while breaking down CertiK’s latest blockchain security report.

How Much Crypto Was Stolen in the First Half of 2025?

According to Gu, the cryptocurrency industry is in an asymmetric conflict with cybercriminals. Gu noted that, besides exploiting psychological loopholes and targeting individuals with the private keys of crypto platforms, it is easier for attackers to exploit single flaws than for platform defenders to secure millions of lines of code.

In its latest report, CertiK highlighted that hackers stole nearly $2.5 billion in crypto in the first half of 2025. Analyzing the report, Gu highlighted the difficulty in eliminating the threat of hackers in the crypto industry, considering the relative ease with which they can find vulnerabilities on decentralized protocols.

The CertiK co-founder acknowledged the improvements in cybersecurity defenses. However, he noted that hackers are becoming more sophisticated. Gu warned that the trend of events points toward a high rate of digital asset theft in 2026, projecting that the volume of digital assets that hackers will steal next year could reach the billion-dollar landmark.

What Are the Most Common Ways Hackers Steal Crypto?

CertiK’s report shows that the crypto industry lost over $2.47 billion across 344 separate incidents between January and June 2025. The vast majority of this came from just 34 wallet compromises, which accounted for a stunning $1.7 billion of the total. Meanwhile, 132 phishing attacks accounted for another $410 million. The data shows that while code exploits happen, attacks targeting people are far more lucrative for thieves, as evidenced by the high value of losses in June from crypto phishing scams and the $42.6 million in crypto losses in May.

Which Blockchain Was Targeted the Most?

The Ethereum ecosystem was the primary target for hackers. CertiK reports that 175 hack incidents were linked to Ethereum wallets, accounting for $1.6 billion of the stolen funds through hacks, scams, and exploits. 

Gu noted that hackers rely heavily on social engineering to trick victims into clicking fraudulent links or signing malicious transactions. These tactics expose private keys and lead to the complete draining of wallets.