A Look Back at 2025 Cybersecurity Trends

One of the best ways for organizations to stay ahead of cybersecurity threats is to learn as much as possible about existing threats and understand the latest trends emerging on the horizon. Mimecast prides itself on being the cybersecurity partner that customers can turn to for that intelligence. We continually publish periodic threat intelligence reports that summarize the current cybersecurity landscape and post threat intelligence alerts to our website as they are discovered.

This year’s threat intelligence report delivered on our promise to keep the industry and our customers informed of the most important things we learned along the way. As 2025 turns to 2026, let’s look back at the top cybersecurity trends for the past year.

Key Findings

Six critical trends defined the 2025 threat landscape, each revealing how attackers adapted their strategies to exploit new vulnerabilities.

1. The Human Element: A Persistent Target

Attackers continued exploiting human vulnerabilities as the weakest link in cybersecurity. Social engineering tactics, such as phishing and business email compromise (BEC), became more sophisticated with the integration of AI. In 2025, these AI-powered attacks mimicked legitimate communications, making it harder for employees to distinguish between real and fake interactions.

Key trends included:

• AI-Augmented Phishing: Automated spear-phishing campaigns and synthetic voices were used to deceive employees.
• ClickFix Attacks: These scams increased 500%, where users are tricked into running malicious commands, highlighting the need for better awareness training.
• Multi-Channel Attacks: Threat actors combined email with phone calls to bypass traditional defenses and exploit psychological tactics.

2. Living Off Trusted Services (LOTS)

Attackers increasingly leveraged legitimate platforms like DocuSign, PayPal, and Salesforce to deliver malicious content. This "living off trusted services" tactic bypassed security controls and exploited organizational trust. Phishing now accounts for 77% of all attacks, up from 60% in 2024, driven by attackers using AI to dramatically increase phishing volume.

Examples included:

• Notification Service Abuse: Phishing emails disguised as legitimate notifications from trusted platforms.
• Link Rewriting: Malicious links embedded in trusted services to evade detection.

Organizations must implement policies and awareness programs to combat these threats effectively.

3. Generative AI: A Double-Edged Sword

AI offers immense potential for improving business workflows but also lowered the barrier for attackers. In 2025, generative AI enabled:

• Hyper-Realistic Phishing: AI-generated emails and deepfake voices created convincing scams.
• Automated Attack Chains: Threat actors scaled operations with minimal effort.

To counter this, businesses must adopt AI-driven security tools and train employees to recognize AI-enhanced threats.

4. Industry-Specific Threats

Attackers tailored their strategies to exploit vulnerabilities unique to different industries. In 2025:

• Real Estate: High-value transactions made this sector a primary target for phishing.
• Manufacturing: Legacy systems and supply chain complexities attracted ransomware attacks.
• Professional Services: Impersonation attacks exploited trust-based relationships.

Understanding these patterns is crucial for prioritizing security investments and training.

5. Collaboration Platforms: A New Battleground

Collaboration tools like Microsoft Teams and SharePoint became critical to remote work but also presented new risks. In 2025, attackers exploited these platforms beyond traditional email security controls:

• Host Malicious Content: Persistent data repositories enabled lateral movement and data theft.
• Conduct Social Engineering: Attackers gained insights into internal processes to craft targeted attacks.

Organizations must deploy data loss prevention tools and establish governance policies for secure collaboration.

6. Business Email Compromise (BEC): Evolving Tactics

BEC attacks surged again in 2025, with a focus on financial fraud. Key trends included:

• AI-Fabricated Email Chains: Attackers used AI to create convincing conversations between vendors and executives.
• Wire Transfer Fraud: Urgent payment requests continued as a common tactic.

To mitigate these risks, companies should implement multi-step verification processes and train employees to recognize BEC schemes.

Emerging Threat Actors and Techniques

2025 saw activity from some of the most prolific threat groups:

• Scattered Spider: Known for advanced social engineering and credential harvesting.
• TA2541: Targeted aviation and transportation sectors with phishing campaigns.
• Storm-1865: Focused on hospitality, using infostealers and spear-phishing.

These groups exemplified the shift toward human-oriented tactics and weaponized trusted services. Organizations must understand these tactics to remain secure.

Vulnerability Landscape

Nearly 40,000 vulnerabilities hit the National Vulnerability Database in 2025, averaging 768 security issues weekly. Only 8.4% qualified as high risk, but the remaining 91.6% created noise that complicated threat identification.

The remediation gap remained alarming. Java flaws had a remediation half-life of 276 days, while vulnerabilities in JavaScript programs had a median fixing time of 163 days. Known vulnerabilities remained exploitable for months, giving attackers ample opportunity to weaponize published exploits against unpatched systems. Organizations need to implement strong vulnerability remediation and attack surface management programs that include maintaining a risk register to track issues and prioritizing software security issues using both exploitability and reachability analysis.

Recommendations for Resilience

To defend against the evolving threats highlighted in this blog, Mimecast recommends a multi-layered approach:

• Enhancing Security Hygiene: Regular training and awareness programs for employees.
• Adopting AI-Driven Tools: Leverage AI to detect and respond to sophisticated attacks.
• Implementing Zero Trust Frameworks: Limit access to critical systems and data.
• Monitoring Trusted Services: Establish baselines to detect anomalies in legitimate platforms.

The Bottom Line

The 2025 threat landscape demands a fundamental shift from reactive security to proactive human risk management. Attackers have industrialized social engineering through AI while weaponizing the very collaboration tools organizations depend on for business operations. The convergence of AI-enhanced attacks, shadow IT proliferation, and supply chain targeting requires organizations to treat employees as the first line of defense rather than the weakest link.

Mimecast analyzed these threats across nearly 43,000 customer environments, providing the threat intelligence that helps security teams stay ahead of attacker innovation. Organizations partnering with Mimecast gain visibility into emerging techniques before they become widespread, turning threat intelligence into actionable defense. Companies that invest in comprehensive security hygiene, implement layered defenses, and maintain robust awareness training programs will be best positioned to navigate 2026's evolving challenges.

To learn more, read the full Global Threat Intel Report 2025, and be sure to visit the Mimecast Risk Radar Threat Intelligence Hub frequently.