Open In App

What is WSDL Attack?

Last Updated : 28 Apr, 2025
Comments
Improve
Suggest changes
Like Article
Like
Report

A web service description language, known as WSDL, is used to describe and expose the interfaces of a system. It makes it possible for users to create software that works with services offered by other providers. When administrators/developers hardcode the URLs and user ids in the software, they are unintentionally leaking information about their systems. This information can be used by hackers illegally to gain access to their systems using a variety of vulnerabilities such as cross-site scripting or SQL injection attacks.

For example, if an application is vulnerable to SQL injection attacks, a hacker will send a query through the application to a website that he plans to target. If the hacker is able to successfully inject malicious SQL code, then he can retrieve information such as usernames and passwords from the database.

In order to prevent WSDL attacks, administrators should avoid hardcoding URLs and user ids in their applications. They should also be aware of insecure coding practices before developing applications; such as failing to deploy input filters, failing to do proper error handling, and failing to validate data. The use of firewalls can also help prevent WSDL attacks.

WSDL Attack Structure

Important points of WSDL Attack

  • WSDL attack is a type of vulnerable or insecure coding practice.
  • Administrators should be aware of insecure coding practices before developing applications; such as failing to deploy input filters, failing to do proper error handling, and failing to validate data.
  • The use of a firewall can also help prevent WSDL attacks by restricting the flow of external connections.

Types of WSDL Attack & Vulnerabilities

There are many types of WSDL attacks here are the few ones:

1. Information Leakage

Think of your WSDL file as the complete blueprint of your web service. If it's publicly accessible, it's like leaving your house’s floor plan on your front porch—anyone can see how to get in. A WSDL file exposes:

  • Endpoints – digital addresses attackers can target
  • Data formats – how requests and responses are structured
  • Hidden or sensitive methods – like adminDeleteUser, getAllTransactions, or resetAccountPIN

In 2022, a financial institution accidentally left a WSDL file accessible online. It exposed a getCustomerSSN method that wasn’t protected. Attackers exploited it and leaked over 500,000 Social Security numbers.

2. WSDL Injection

WSDL defines how inputs are sent. Attackers can exploit that by injecting malicious inputs, similar to SQL injection but inside XML-based web services. These WSDL injection attacks can:

  • Crash the service by submitting oversized or malformed data
  • Execute unauthorized commands if backend validation is poor
  • Exfiltrate sensitive data by altering expected input behavior

Example Attack:

<!-- Normal -->
<getUser><id>101</id></getUser>

<!-- Malicious Injection -->
<getUser><id>101; EXEC xp_cmdshell('format C:')</id></getUser>

3. Cross-Site Request Forgery (CSRF)

Hackers can use WSDL-exposed methods to perform CSRF attacks. If a user is already authenticated, a malicious script can silently execute functions defined in the WSDL—like transferring funds or changing user settings.

Example Scenario:

  • A victim is logged into a banking dashboard.
  • They click a seemingly harmless link.
  • The link calls a WSDL-exposed method like transferFunds.
  • Money is moved without the user knowing.

4. Denial of Service (DoS)

Attackers can discover WSDL endpoints and then use them to launch DoS attacks by bombarding the service with automated, repeated requests. This can overwhelm system resources, crash servers, and cause downtime—especially during peak hours like sales events or product launches.

  • WSDL attacks are another type of SQL injection attack. They are commonly used to retrieve sensitive data.
  • Administrators should ensure there is no malicious access to the WSDL itself. In other words, if an application uses a WSDL file, it should be carefully checked for threats before deployment.
  • Even if an application does not have any vulnerabilities or weak spots that can be exploited by a hacker through an external website, the fact that it uses WSDL means that there might be some information about the targets' infrastructure exposed on the web by default.
  • A The WSDL file can be changed without knowing the target's IP or User Id.
  • An attacker can use the information obtained from the WSDL file to attack the application being used by others.
  • WSDL files are also more portable and can be uploaded to a site and used for access as well as web attacks.

Real-World WSDL Attack Examples

WSDL (Web Services Description Language) files are often overlooked, but they can expose sensitive functions of a web service to attackers. If not secured properly, WSDL files can be scanned, interpreted, and exploited — leading to real-world consequences. Below are real examples of WSDL-based attacks that highlight the importance of securing your API and SOAP endpoints:

Retail Breach (2023)

In this case, attackers gained unauthorized access to exposed WSDL files on an e-commerce platform. These files revealed API functions that lacked proper authentication. By sending crafted SOAP requests, hackers bypassed user controls and stole over 2 million customer records, including emails, order history, and contact information. This highlights how WSDL exposure can directly lead to massive data leaks in the retail sector.

Healthcare API Exploit

In a major healthcare system, attackers manually scanned available WSDL files and guessed undocumented or poorly secured methods, such as getPatientSSN. Since these endpoints weren’t properly authenticated, malicious users were able to extract sensitive data like social security numbers (SSNs), medical IDs, and patient history. This shows how WSDL enumeration can reveal dangerous entry points when security checks are missing.

Banking DoS Attack

Some attackers targeted banking systems by identifying SOAP-based services via their WSDL files. Once they mapped the available functions, they flooded the loan approval endpoints with thousands of fake requests per second. This caused a denial-of-service (DoS), slowing down or crashing services for real users. The incident proved how open WSDL interfaces can be abused for large-scale performance-based attacks.

Conclusion

Ethical hackers should use similar methods to prevent WSDL attacks as they would be used in other web application vulnerabilities. They should also avoid confusing the client and WSDL file. The deployment of input filters is also important.

WSDL is a standard used to describe web services; it needs to comply with certain rules. It needs to follow a certain format in order to be accepted, and so it can prevent WSDL attacks from being performed. When you are developing your own application, you do need to follow the standard because if you don't, then your application will not work with most of the applications.


Similar Reads