Do you know that little things like the errors displayed when something goes wrong in your application could be a potential vulnerability? Every vulnerability has its level of severity; critical, high, medium, and low. Improper error handling vulnerabilities are usually low to medium vulnerabilities that attackers can leverage to discover even higher severity vulnerabilities.
So how are you handling your application’s vulnerabilities? Are the errors displayed giving an attacker a leeway to exploit you? Read on to discover what improper error-handling vulnerabilities are and how you may protect your software.
What Are Improper Error-Handling Vulnerabilities?
As the name implies, improper error handling vulnerabilities are vulnerabilities that occur when a program or application fails to handle errors, exceptions, or unexpected conditions properly. This can include server errors, failed login attempts, failed transactions, input validation errors, and so on.
Errors are normal occurrences and should be expected. The problem lies when these errors are not appropriately managed. A good error message or page should only provide the necessary information a user needs to understand what occurred and nothing more. Attackers can use improperly handled errors to gain information on the application and even identify vulnerabilities.
The Impact of Improper Error-Handling Vulnerabilities
As we mentioned earlier, improper error-handling vulnerabilities are usually the stepping stones to even more dangerous vulnerabilities. Even the minutest of information disclosed or even a variance in an error message could tip off an attacker to discover a vulnerability.
Improper Error Handling Vulnerabilities can lead to information disclosure vulnerabilities, SQL injections, account enumeration, session misconfigurations, and file inclusion. Let’s look to see how this vulnerability can be exploited on an application.
1. Account Enumeration
Imagine you try to log into an application with the wrong email and password, and it gives the error, ‘Invalid username or password.’. But when you try to log into the same application with the correct email this time but a wrong password it shows this error: ‘Invalid username or password’.
At a glance, these two error messages look the same, but they are not. Take a closer look, and you will notice that the second message doesn’t have a full stop like the first. This might be easy to ignore, but attackers are looking for little details like this. Using this slight difference in the error message, the attacker can enumerate valid usernames on the application and filter out the responses that do not have full stops.
Then, armed with the list of valid account names, he can take the next step to brute force the account’s password for weak passwords or send a phishing message to the unsuspecting user.
Another improper error handling vulnerability lies in reset or forgot password pages. For many web applications, when you enter a username or email to reset the password, it tells you if the username or email exists on their database. This is wrong. A malicious actor can use this information to enumerate the valid usernames on the applications and escalate the vulnerability viabrute force attacksor phishing.
The message should be the same regardless of whether the username is valid or not. Ideally, it should look like this:If you have a valid account, the necessary password reset steps have been sent to your email address.
2. Error-Based SQL Injection
SQL injection attacksare a prevalent type of attack in which hackers inject malicious SQL code into an application’s database to gain unauthorized access to information. One specific variation of SQL injection, known as error-based SQL injection, capitalizes on improper error-handling vulnerabilities.
Error-based SQL injection attacks utilize special characters and SQL statements to intentionally trigger the application to generate error messages. These error messages can inadvertently reveal sensitive information about the database, including:
This type of attack is particularly dangerous because it discloses critical information that can aid attackers in further exploiting the application or database. Therefore, it’s crucial for developers to implement proper error-handling mechanisms to mitigate the risk of error-based SQL injection attacks
3. Information Disclosure
Information disclosure vulnerabilitiesand improper error handling vulnerabilities are usually linked together. Information disclosure vulnerabilities refer to security weaknesses in a system or application that unintentionally expose sensitive information to unauthorized users.
For example, a poorly-handled error message might expose the type and version of the web server, the programming language in use, or the database management system. Armed with this information, attackers can tailor their attack strategies to target known vulnerabilities associated with specific software versions or configurations, potentially leading to successful cyberattacks or further reconnaissance efforts.
How to Prevent Improper Error Handling Vulnerabilities
Now that you’re aware of the impact of improper error handling on the security of your application, it is important to know how to effectively mitigate these vulnerabilities to protect yourself. Here are some ways to prevent improper error-handling vulnerabilities:
Carry Out Regular Security Testing
Vulnerabilities like improper error handling and other security weaknesses can be discovered and mitigated through regular security tests. Penetration tests simulate real cyberattacks to enumerate the various weaknesses you might have on your system or application. These tests help you find out these vulnerabilities before an attacker does and this way, you are able to improve your organization’s security posture and keep yourself and users safe.
