Preventing Session Fixation Attacks on Finance Applications

If you work in banking or finance IT, attackers stealing your customer data is pretty much the worst case scenario. Your institution could lose money on the spot, be subject to regulatory penalties and face a tidal wave of negative PR. One of the most common ways this could occur is via a session fixation attack.

Session fixation is a cybersecurity vulnerability that allows an attacker to hijack a valid user’s session within a web application, effectively enabling unauthorized access to sensitive information and functionalities. This attack is particularly insidious because it directly targets the user rather than the organization or infrastructure. In finance applications, they happen when a user is accessing their most sensitive and valuable data. 42% of dark web advertising messages focus on the sale, purchase, or distribution of the client data of financial companies.

Let’s dive into how session fixation attacks work in the wild and what you can do to prevent them from potentially ruining your week. 

How do Session Fixation Attacks Work?

An attacker exploits the management of session identifiers (IDs) that web applications use to maintain state and track user activities during a session. A user session is essentially a series of interactions between a user and a web application during a given period. To keep track of these interactions without requiring the user to re-authenticate for each action (thereby “maintaining state”), web applications assign a unique ID to each user session.

Session IDs are crucial because they allow the application to remember who the user is and maintain the continuity of their interactions. A simple example is: when you log into your online banking account, the session ID helps the bank’s web application keep you logged in as you navigate through different pages to view your balance, make transfers, etc.

In a session fixation attack, the attacker predefines or “fixates” a session ID, tricking the victim into using this predetermined session ID. Once the victim logs in using the fixated session ID, the attacker gains access to the user’s session, bypassing authentication mechanisms to assume the identity of the victim.

Session Fixation in the Finance Sector

In the finance sector, applications often manage highly sensitive transactions and personal data, making them attractive targets for session fixation attacks. Financial applications, from online banking portals to trading platforms, rely on sessions to authenticate users before allowing access to account information, transaction functionalities, and personal data. Attackers can exploit these vulnerabilities to manipulate account settings or transaction details, access confidential account information or even execute unauthorized transactions. 

The ramifications of a successful session fixation attack on a financial application can be significant. Unauthorized transactions resulting from such an attack can lead directly to financial loss, impacting both customers and the institution itself. The loss of customer trust in the wake of such breaches can have enduring effects on an institution’s reputation, potentially causing a significant loss of business. 

The exposure of personal financial data frequently results in non-compliance with regulatory requirements like the General Data Protection Regulation (GDPR), California Consumer Privacy Act (CCPA), or the Gramm-Leach-Bliley Act (GLBA). This leads to legal penalties and fines, compounding the financial damages. Addressing the consequences of a session fixation attack can significantly disrupt normal operations. The organization must divert resources from other areas to manage the fallout. This compounds the other consequences listed above as it continually hinders the institution’s ability to deliver services effectively.

Preventing Session Fixation Attacks

Best Practices

1. Regenerate Session ID

Once you understand session fixation and set your mind to stopping it, there are some relatively easy steps you can take to mitigate a large portion of the risk associated with these vulnerabilities. First, always regenerate the session ID after a successful login. By doing this, any session ID provided by an attacker before authentication becomes obsolete. In Java, this can be achieved by calling HttpSession.invalidate() to invalidate the current session and then creating a new session. This process ensures that even if an attacker has fixed a session ID before login, the newly generated session ID post-authentication remains secure and unique to the authenticated user.

Another crucial practice is to implement secure cookie attributes such as HttpOnly and Secure. Setting the HttpOnly attribute ensures that cookies cannot be accessed via client-side scripts, reducing the risk of Cross-Site Scripting (XSS) attacks exploiting session IDs. The Secure attribute ensures that cookies are only sent over HTTPS, protecting them from being intercepted in transit. Additionally, configuring the SameSite attribute to Strict helps prevent the session cookie from being sent along with cross-site requests, mitigating Cross-Site Request Forgery (CSRF) attacks.

3. Timeout and Inactivity Mechanisms

Finally, you want to make sure you’re setting appropriate session timeout values and implementing session inactivity mechanisms. By setting a reasonable timeout value for sessions in Java, using session.setMaxInactiveInterval(), you ensure that sessions do not remain active indefinitely, reducing the window of opportunity for an attacker. Additionally, incorporating a re-authentication mechanism for critical financial transactions ensures that even if a session is hijacked, unauthorized actions are prevented.

Use Waratek to Automatically Protect Against Session Fixation 

Waratek’s approach for mitigating session fixation centers around enhancing session management mechanisms. We do this by reinforcing the processes by which session identifiers (IDs) are generated and managed. By implementing cryptographic techniques and entropy in the session ID generation process, Waratek makes it considerably more difficult for attackers to predict or reuse session IDs, eliminating a key vector for session fixation attacks.

Next, we employ dynamic session validation techniques, which involve continuously monitoring session activities and comparing them against established patterns of user behavior. Using this ongoing validation process, we are able to identify anomalies that may signal an attempt at session hijacking. Waratek’s system understands the normal sequence of actions a user takes within an application, and flags deviations from this pattern. These might include unexpected requests or changes in user state that are indicative of session fixation or hijacking attempts.

In addition to these technical measures, Waratek enables security teams in the financial sector to define custom security policies tailored to their unique needs and threat profiles. These policies offer a level of customization that generic security solutions cannot match. By leveraging Waratek’s deep understanding of the financial sector’s regulatory environment and security challenges, these custom policies act as further defense layer against more sophisticated attack vectors.

Finally, Waratek implements real-time monitoring and automated response capabilities. Our platform continuously scans for signs of session fixation and other security threats, offering immediate automated interventions to mitigate any detected attacks. This ensures that threats are neutralized swiftly, minimizing potential damage to the application and its data.

To get started using Waratek to automatically defend against session fixation attacks in your finance applications, click here. 

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