In July 2023, a serious breach involving Ivanti’s EPMM surfaced due to the CVE-2023-35078 zero-day vulnerability. Attackers exploited this flaw, gaining unauthorized API access, manipulating server functions, and potentially exfiltrating sensitive data, highlighting urgent API security needs.
This vulnerability, known as API6:2023 is a severe threat to businesses, as it allows unauthorized access to critical operations that can lead to severe consequences. Understanding this risk is essential for developers, security professionals, and organizations striving to protect their APIs and sensitive data.
This blog post tries to explore API6:2023 – Unrestricted Access to Sensitive Business Flows risks, their impacts, and ways to deal with such risks.
What is Unrestricted Access to Sensitive Business Flows?
API6:2023 refers to a specific vulnerability identified in the OWASP Top 10 API Security Risks list. It highlights scenarios where APIs expose sensitive business processes without appropriate access controls.
This lack of restriction can allow attackers to exploit these flows, potentially causing significant damage to the organization. Sensitive business flows encompass various operations critical to an organization’s functionality, such as financial transactions, user data management, and administrative tasks.
When threat actors can access these flows without proper safeguards, they can automate requests to manipulate or abuse these processes for personal gain.
Use Cases of API6:2023 in Action
To better understand the implications of API6:2023, let’s explore several real-world scenarios where this vulnerability could be exploited:
Ticket Scalping
An attacker could exploit an API allowing users to purchase popular event tickets. By automating requests through the API, they could buy many tickets before legitimate users have a chance, later reselling them at inflated prices.
Spam Content Creation
If an API allows users to post comments or reviews without sufficient restrictions, an attacker could automate the submission of spammy content. This could overwhelm the system and degrade the user experience for genuine customers.
Resource Reservation Abuse
Threat actors could programmatically reserve all available slots using automated scripts when an API manages bookings (e.g., hotel rooms or restaurant reservations). This would prevent legitimate users from accessing those services and could lead to significant revenue loss for the business.
Unauthorized Financial Transactions
Attackers could initiate unauthorized transactions if a payment processing API lacks proper authentication and authorization checks. This could damage customer trust and lead to regulatory penalties.
API6 Example Scenarios
Here are the following three example scenarios of how an attacker can exploit such vulnerabilities:
Scenario # 1 Ticket Scalping Attack
Gaming announces the launch of a highly anticipated gaming console with limited stock on Thanksgiving day. In anticipating high demand, an attacker develops a script to automate purchases through the company’s API.
On release day, the attacker deploys this code across multiple IP addresses to bypass any potential rate limiting or access controls.
As a result, the attacker successfully buys most of the available stock before legitimate customers can make their purchases. Subsequently, the attacker lists these consoles on secondary marketplaces at significantly inflated prices, capitalizing on the scarcity and high demand, thus profiting from their malicious actions.
Example Scenario #2 Airline Ticket Abuse
An airline offers online ticket purchasing with a no-cancellation fee policy, attracting customers looking for flexibility. A malicious user exploits this by booking 90% of the seats on a famous flight.
As the flight date approaches, this individual cancels all their tickets simultaneously, creating an artificial scarcity that forces the airline to lower ticket prices to fill the remaining seats.
With prices discounted, the attacker then purchases a single ticket at a much lower cost than initially advertised. This manipulation harms the airline’s revenue and disrupts the travel plans of genuine customers who may have wanted those seats.
Example Scenario #3 Referral Program Exploitation
A ride-sharing app introduces a referral program that rewards users with credits for inviting friends to join. An attacker sees an opportunity and writes a script to automate registering numerous fake accounts, each linked to their referral code.
As new users sign up, credits are automatically added to the attacker’s account. Over time, this accumulates credits that can be redeemed for free rides.
The attacker can either use these credits for personal gain or sell accounts loaded with credits to others for cash, undermining the integrity of the referral program and costing the company significant revenue.
Potential Impact of Unrestricted Access to Sensitive Business Flows
The potential impacts of unrestricted access to sensitive business flows can severely affect an organization’s operations:
Exhausting Server Resources
Attackers can overload servers with excessive requests, leading to performance degradation or complete service outages.
Service Disruption
A high volume of automated requests can result in Denial-of-Service (DoS) attacks, disrupting services for legitimate users and affecting business continuity.
Data Breaches
If attackers gain unauthorized access to sensitive data through compromised APIs, it can lead to significant data breaches with legal and financial repercussions.
Account Takeover (ATO)
Attackers may exploit vulnerabilities in authentication mechanisms to gain control over user accounts, leading to identity theft and fraud.
Creation of Fake Accounts
Automated scripts can create numerous fake accounts, which can then be exploited for malicious purposes or spam campaigns.
Scalping at Scale
By exploiting APIs that manage high-demand products or services, attackers can acquire inventory quickly and resell it at inflated prices.
Content Scraping
Attackers may scrape content from websites using APIs without restrictions, undermining intellectual property rights and competitive advantages.
How to Prevent Unrestricted Access to Sensitive Business Flows Attacks Via APIs
Implement multi-factor authentication (MFA) alongside strong authentication methods like OAuth 2.0 or JWT to secure API endpoints effectively.
This adds an extra layer of security, ensuring that even if credentials are compromised, unauthorized access is still mitigated.
Role-based access control (RBAC) should be enforced to limit user permissions based on their roles, preventing unnecessary exposure to sensitive operations and data. Access permissions should be regularly reviewed and updated to adapt to changing user roles and security needs.
Rate Limiting
To effectively mitigate API abuse, implement rate limiting by setting specific thresholds for the number of requests a user can make within a defined timeframe.
For instance, use fixed-window rate limiting to allow 100 requests per minute. This approach helps prevent automated attacks, such as DDoS, from overwhelming your system.
Additionally, consider using dynamic methods like sliding window or leaky bucket algorithms to adapt to varying traffic patterns and maintain optimal service quality. Regularly monitor usage patterns and adjust limits to balance user experience with security needs.
Input Validation and Data Sanitization
Always validate client input to ensure it conforms to expected formats and types. This prevents malicious data from being processed, which could lead to security vulnerabilities such as SQL injection or cross-site scripting (XSS).
Implement strict data sanitization routines to clean inputs, removing harmful characters or scripts before they reach the backend. Regularly update validation rules to adapt to evolving threats.
Logging and Monitoring
Maintain comprehensive logs of API access, capturing details about requests, responses, and user actions. Monitor these logs for unusual patterns or spikes that could indicate an attack. Implement automated alerts for critical events, such as repeated failed login attempts or access violations.
Ensure logs are stored securely and are tamper-proof, enabling practical forensic analysis in case of a breach.
Regular Security Testing
Conduct regular security assessments, including penetration testing and code reviews, to identify vulnerabilities in your APIs. Automated tools scan for common weaknesses, but manual testing for nuanced vulnerabilities complements them.
Establish a routine schedule for these assessments and ensure findings are prioritized and addressed promptly to mitigate risks before attackers can exploit them.
Use API Scanners Security Tools
Consider utilizing tools like the BugDazz API scanner, which can help identify vulnerabilities in your APIs through automated scanning and testing processes. By implementing these protective measures, organizations can significantly reduce their risk exposure related to unrestricted access vulnerabilities in their APIs.
Conclusion
Unrestricted Access to Sensitive Business Flows represents a critical vulnerability that organizations must address as part of their overall security strategy.
By understanding this threat and implementing robust security measures, businesses can protect themselves from potential exploitation that could lead to significant financial losses and reputational damage.Developers and security professionals alike need to prioritize securing their APIs against such vulnerabilities in an increasingly interconnected digital landscape.
