What Are Lessons Learned from the Biggest Financial Sector Cyber Breaches?

Why the Financial Sector Remains a Top Target

An industry under constant threat from ransomware, supply chain compromise, and cloud misconfiguration

Financial institutions store high-value data and underpin global economic activity. In 2025, this makes them a continuous target for cyberattacks. From multinational banks to fintech startups, attackers exploit third-party vulnerabilities, unpatched infrastructure, and cloud misconfigurations to infiltrate financial networks.

Threat research from SecurityScorecard reveals that third-party data breaches have affected 97% of the top 100 U.S. banks. That scale of exposure signals a pressing need for stronger third-party oversight and continuous monitoring. Fintech entities experience a significant amount of vulnerability as well—41.8% of breaches in fintech originate from third parties, according to new SecurityScorecard research from 2025.

The Stakes for Financial Services

A breach in this sector carries consequences beyond operational disruption. Financial institutions risk:

• Regulatory fines under GLBA, NYDFS, and the SEC cyber disclosure rules
• Reputation loss and customer attrition
• Share price volatility
• Erosion of trust from business partners and investors

Attackers exploit the financial sector’s interconnectedness. A single third-party compromise can create cascading impacts across payment processors, insurers, and core banking systems.

Case Study: Capital One

In 2019, a former Amazon Web Services (AWS) employee exploited a misconfigured firewall and gained access to over 100 million records. This included information on customers’ addresses, phone numbers, Social Security Numbers, and bank account information.

What happened: A server-side request forgery (SSRF) flaw allowed the hacker in and the web application firewall (WAF) failed to detect the exploit.

Key lessons:

• Cloud-native applications need continuous configuration checks
• Cloud security must be built-in from the outset
• WAFs must be tested for bypass techniques

Case Study: Equifax

The 2017 Equifax breach exposed personal data from 147 million individuals. Attackers exploited an unpatched vulnerability in Apache Struts (CVE-2017-5638) that went unresolved for months.

What happened: Patch management gaps allowed hackers to exploit a known vulnerability, asset inventories and vulnerability scanning didn’t accurately address all assets, and hackers were able to pivot internally.

Lessons learned:

• Implement diligent patching programs and asset management programs
• Vulnerability management must be continuous, not episodic
• Asset inventories must be complete and actively maintained
• Network segmentation is crucial to prevent attackers’ movement after initial breach

Case Study: First American Financial Corporation

In 2019, a web application flaw allowed unauthenticated access to millions of documents related to mortgage deals. Bad actors didn’t need sophisticated hacking tools—just knowledge of the URL format and ability to change even one character in the URL.

What happened: There were insecure direct object references (IDOR) and no access controls validating user permissions.

What this highlights:

• Security teams must regularly test for both business logic issues and technical flaws
• Security monitoring must detect high-volume access and flag anomalies

Patterns Across Financial Breaches

While these incidents differ in method, they share key failure points:

Third-party risk
Many institutions failed to assess vendor security posture beyond questionnaires. SecurityScorecard’s breach research shows that attackers frequently enter through third-party vendors in the financial sector. According to SecurityScorecard’s 2025 Global Third Party Breach Report, financial services make up the fourth-most breached industry through third parties.

Configuration gaps
Weak defaults, unused open ports, and over-permissioned roles remain common. Shared cloud infrastructure, if misconfigured, becomes a silent entry point.

Delayed patching
Unpatched software continues to be exploited. Attackers look for known CVEs that haven’t been addressed.

Poor detection and response
Many breaches were discovered late—or by third parties—because of inadequate logging or alert fatigue.

Unclear governance
Teams lacked clear roles and processes for incident response, leading to delayed containment and regulatory non-compliance.

What Financial Institutions Must Do in 2025

Cybersecurity maturity now requires real-time visibility across internal systems and third-party relationships. To reduce breach risk, financial firms should:

• Continuously monitor vendors: Use platforms like SecurityScorecard to detect risk indicators in real time
• Implement CIS Controls and NIST CSF: Use these frameworks to structure and prioritize technical safeguards
• Apply least privilege and zero trust: Across both internal teams and external vendors
• Validate software supply chain security: Require proof of SDLC practices and source code validation
• Train all stakeholders: Ensure incident response plans include legal, comms, and operations—not just IT

SecurityScorecard’s MAX managed service helps organizations operationalize third-party risk reduction by delivering assessments, alerts, and remediation support at scale.

Final Thoughts: Breach Lessons Must Drive Change

Some of the most damaging attacks in the financial sector typically stem from preventable failures such as missed patches, unmonitored vendor access, or unclear response plans. These aren’t just technical failures—they’re leadership and process failures.

In 2025, financial firms must move beyond checkbox compliance and toward integrated cyber resilience. Boards, customers, and regulators now expect visible progress and accountability.

SecurityScorecard empowers financial institutions to reduce risk by delivering intelligence, visibility, SOC automation capabilities, faster threat detection and response times, and and remediation support across third-party ecosystems.

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