The final weeks of 2025 provided a stark demonstration of what happens when API security is treated as an afterthought. While many companies remain focused on firewalls and endpoint security, attackers are systematically exploiting the Achilles’ heel of modern infrastructure: poorly secured APIs. Two incidents from December 2025 serve as prime examples of why continuous API Security Testing is no longer an option, but a necessity.
The 700Credit Incident: Anatomy of an Avoidable Data Theft
On October 25, 2025, the financial services company 700Credit discovered that customer data had been systematically exfiltrated over a period of five months. The fallout: 5.8 million consumer records—roughly 20% of their entire database. Names, addresses, social security numbers, and complete financial histories were now in the hands of criminals. The real scandal? The vulnerability was a textbook example of one of the oldest known API security flaws.
How the Attack Unfolded
In July 2025, attackers first compromised one of 700Credit’s partner companies. Within that partner’s logs, they found technical details regarding API access. The vulnerability was simple: The API relied on “Consumer Reference IDs” to identify consumers. Anyone sending such an ID to the corresponding endpoint received the full data set in return—without any check to verify if the requester was actually authorized to access that specific data.
Between May and October 2025, the attackers launched a Velocity Attack: they systematically cycled through different IDs and downloaded the associated data. The system lacked reasonable rate limits or anomaly detection. It took five months for anyone to notice something was wrong—five months during which a simple API test could have prevented the entire incident.
The Problem: Broken Object Level Authorization
In API security, this is known as “Broken Object Level Authorization” (BOLA), and it holds the #1 spot on the OWASP API Security Top 10 for a reason. The principle is simple: Every API request must not only verify “is the user logged in?”, but also “is this specific user allowed to access this specific resource?”. Authentication alone is insufficient—without object-level authorization, every logged-in user is a potential data thief.
A systematic API security test would have identified this vulnerability in minutes: You create two test accounts, authenticate with Account A, and attempt to access resources belonging to Account B. Automated API Security Testing platforms—like the system developed at Venedy—address exactly this problem. They automatically generate different user contexts and systematically test whether account separation is functioning. The crucial advantage: These tests run continuously, not just once before a release.
React2Shell: When the Time Between Disclosure and Exploitation Vanishes
While the 700Credit incident exposes the problem of inadequate testing, the React2Shell vulnerability highlights a different dilemma: Even if you test your APIs, it is no longer enough when the window between the disclosure of a vulnerability and its mass exploitation shrinks to a matter of hours.
The Vulnerability
On December 3, 2025, CVE-2025-55182 was published—a critical Remote Code Execution (RCE) vulnerability in React Server Components with the maximum possible CVSS score of 10.0. The vulnerability exploits how server components deserialize data. Attackers send specially crafted data that creates a self-referential loop, tricking the server into executing attacker code. The result: full server compromise with a single HTTP request.
Exploitation in Hours
Mere hours after publication, security researchers observed the first exploitation attempts. Within 24 hours, various threat groups were active, including the RondoDox botnet and Chinese APT groups. GreyNoise identified over 362 unique attacker IPs actively scanning for vulnerable systems. The vulnerability was quickly integrated into Mirai botnet variants and leveraged by ransomware groups.
By late December 2025, approximately 90,300 vulnerable instances were still accessible on the internet—68,400 in the USA and 4,300 in Germany. Over 30 organizations had already suffered confirmed compromises, ranging from data loss and ransomware extortion to full infrastructure hijacking.
The New Paradigm: Continuous API Security
React2Shell makes it clear why traditional approaches—“we test before every release”—are no longer sufficient. The vulnerability lay within React itself, not in the affected companies’ code. When the vulnerability became public, they had literally hours, not days, to react.
API Security must be continuous, not episodic. APIs change constantly—new dependencies, framework updates, modified third-party services. Every change can introduce new vulnerabilities. When a critical vulnerability in a widely used component becomes known, you need to know within hours: “Are we affected? And exactly where?”
This is where the advantage of agent-based API testing systems becomes apparent. An agent can automatically explore an API, discover new endpoints, understand relationships, and generate intelligent test cases. When a new vulnerability is disclosed, it can automatically check if the monitored APIs are affected—without a human needing to write new test scripts first.
What These Incidents Mean
The combination of 700Credit and React2Shell paints a clear picture of the current threat landscape. On one hand, we have known vulnerability classes like BOLA, which have been in the OWASP Top 10 for years yet still make it into production. On the other hand, we have Zero-Day vulnerabilities in widely used frameworks that are exploited en masse within hours.
The traditional response—more manual tests, more code reviews, more security awareness training—is necessary, but not sufficient. What we need is intelligent, continuous testing that:
- Automatically understands how an API functions.
- Tests for relevant vulnerability classes in a context-aware manner.
- Runs continuously, not just before releases.
- Can react rapidly to new threats.
These are precisely the capabilities being developed at Venedy. The goal is not to replace penetration testers—their expertise remains indispensable. But for the continuous, systematic securing of APIs against known vulnerability classes and for rapid response to new threats, we need automated, intelligent systems.
The incidents of December 2025 are not anomalies. They are the new normal. APIs are the attack surface of modern software, and this attack surface grows daily. The question is not whether we need better API security—the question is how quickly we can implement it.
Sources
700Credit Data Breach:
- SecureMyOrg: How to Identify and Fix BOLA Vulnerabilities in Your APIs
- Qodex: Common API Security Vulnerabilities & Solutions
React2Shell (CVE-2025-55182):
- Bleeping Computer: React2Shell flaw exploited to breach 30 orgs
- Cloudflare: WAF proactively protects against React vulnerability
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