Injection attacks pertain to the extensive class of attack vectors which gives an attacker a chance to supply an unreliable input into a program. This then gets processed by the interpreter as a part of a query or command that changes the program’s course of execution. Injection attacks are some of the oldest and also most dangerous attacks on web applications. These can lead to data loss, data theft, denial of service, loss of data integrity, and full system compromise.
These attacks are major concerns in web security. This is considered as the number one security risk in web applications and this is for a good reason. These injection attacks, specifically Cross-site Scripting (XSS) and SQL injection are not just very dangerous as these are also extremely widespread, particularly in legacy applications.
Injection attacks are particularly scary because of their enormous attack surface, specifically for XSS and SQLi. Aside from that, injection attacks are a vulnerability class that is well understood. This means that there are a lot of freely reliable and available tools that give even the most inexperienced attackers a chance to abuse such vulnerabilities with great ease.
Common Types of Injection Attacks
Although Cross-site Scripting (XSS) and SQL Injection (SQLi) are the most discussed injection attacks, there are still several types out there. These include the following:
- Code Injection – This type of attack injects the application code that can execute commands of the operating system as the user runs the web application. More advanced attacks can also use privilege escalation vulnerabilities to get higher privileges if needed. This can then lead to a full system compromise.
- CRLF Injection – It is an attack that injects an unexpected Carriage Return and Line Feed or CRLF character sequence being used for splitting an HTTP response header and writing arbitrary contents to response body, which includes Cross-Site Scripting (XSS).
- Email (SMTP/mail command) Injection – This injects SMTP/IMAP statements to the email server which is not available directly through a web app. Information disclosure and spam relay are some of its effects.
- Host Header Injection – This attack abuses the HTTP Host Header’s implicit trust for poisoning web caches and password-reset functionality.
- LDAP Injection – This injects Lightweight Directory Access Protocol or LDAP statements for executing arbitrary LDAP commands that include changing the contents of the LDAP tree and granting permissions. Some of its impacts include privilege escalation, authentication bypass, and information disclosure.
- OS Command Injection – This can inject operating system commands while the user runs the web app. The more advanced types of this attack can also leverage the privilege escalation vulnerabilities that can cause a full system compromise.
- SQL Injection (SQLi) – It injects the SQL commands which can modify or read data from the database. The advanced variations of such attack can also be used for writing arbitrary files to a server as well as execute the commands of the operating system that can result to a full system compromise.
- XPath Injection – It injects data in an app to execute crafted XPath queries that can be used for accessing unauthorized data as well as bypass authentication.
Prevention Tips for SQL Injection Attacks
There are numerous things that site owners can do for preventing SQL injection attacks. Even if there’s no such thing as foolproof solution in a network security, some formidable obstacles may be placed in the way of the SQL injection attempts.
Below are some of the steps you may take to minimize the risk of becoming a victim to SQL injection attacks:
Assume that user-submitted data is evil. For this reason, use input validation through a function to ensure that any dangerous characters aren’t passed to the SQL query in data. You must also sanitize all things through filtering user data.
Update and Patch
Vulnerabilities in databases and apps that hackers may exploit using SQL injections are discovered regularly. Therefore, it is important to apply updates and patches as soon as possible. Patch management solutions are worth your investment.
Never Use Dynamic SQL
Never construct queries with a user input. You have to take note that even data sanitization routine can be flawed. Thus, use prepared statements, stored procedures or parameterized queries if possible. However, never forget that while the stored procedures prevent some of kinds of SQL injection attacks, they may fail to protect against others, so never rely on their use for security.
Minimize Your Attack Surface
Eliminate database functionality that you do not need to prevent hackers taking advantage of it. This will help you avoid SQL injection attacks.
The Solution to Prevent Injection Attacks
Luckily, these kinds of injection attacks can be defeated easily. The first thing that you should do is to validate input. For instance, there are several sites that enable markup of comments, yet use square brackets rather than angle brackets that are used by an HTML markup. Through this, it’s easy to get rid and detect HTML markup or block posts.
SQL injection attacks can be defeated through examining input data. There is no reasonable name with semi-colons in it. Your grammar checker can help you point it out. Aside from that, script writers may prepare SQL statements so input will be directly into the database as well as not processed by SQL engines. With this, combined with input sanitization, gives protection against injection.
Virtually, every scripting language used online is subject to an injection attack. Several treat input data, so programmers are strongly motivated for sanitizing it. It can be hard to believe that attacks are very easy to prevent are prevalent. It also shows that programmers aren’t learning the ways to code securely. Test your websites for the vulnerabilities of injection. Help the programmers learn the ways to secure codes.
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