The Potential Dangers of Web Services

Web services are vital components for connecting internet users with the back-end data of a website.  At the same time, they also create a number of entry points that a hacker can use to gain illegal access to a website or server.  These potential security flaws must be addressed immediately in order to prevent a broad range of attacks from occurring.  Below are just a few of many exploits you need to be concerned about:

When successfully exploited, web services can be used to aid various types of buffer overflow attacks, which often results in a data corruption, DOS (Denial of Service) attacks and the execution of malicious code.  A crafty attacker can assemble XML data that forces the markup language to repeatedly call upon itself and dramatically increase in size.  The result is a memory overflow or error message that reveals details about the application to the attacker.  A similar attack involves sending a block of data to an application stored in an overflown buffer.  From here, legitimate data can be overwritten and result in a function return that gives the hacker complete control of the malicious code they inserted in the data block.

The successful exploitation of web services can also result in XML injection, which can lead to data theft and deletion, the remote execution of malicious code and schema poisoning.  The most common form of XML injection is known as SQL injection, a devastating technique that exploits improperly validated data through SQL queries.  When left vulnerable, a simple web form can provide a hacker with access to sensitive data and allow them to execute malicious code that compromises the entire server.

Another common example of XML injection is a method called schema poisoning.  Schema files contain vital preprocessor details an XML parser needs to comprehend grammar and structure.  An attacker can damage a schema or replace it with a modified version, thus allowing the parser to process malicious messages or harmful XML files and insert dangerous OS commands into the database or web server.

If a hacker can exploit web services, they can stir up a lot of trouble through a malicious technique known as session hijacking.  This practice refers to gaining unauthorized control of an authorized user’s session state by sniffing or intercepting session data.  Session hijacking can give an attacker access to a valid session ID and allow them to enjoy whatever privileges the legitimate user has within the application.  Once they have been validated as an authentic user, the attacker can perform a wide range of dangerous activities on the system.

Web services provide an easy way for many different technologies to interact and communicate with each other.  Due to their increasingly popularity and natural functionality, they present a huge risk to the web servers and applications hosting them.  While the concern has been raised among security teams and developers, awareness has not been increased enough because web services continue to lead to website exploits and compromised data at an alarming rate.