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Top Injection Attacks and How to Avoid Them

by GuardRails on February 13, 2023

Injection Attack Overview

An injection attack is a form of cyberattack in which information is sent to alter the system’s interpretation of commands. An attacker sends harmful information to the interpreter during an injection attack. An injection attack can be done on data from many different places, like environment variables, parameters, online services, and user types, but not just those. The OWASP Top 10 highlights injection attacks as critical vulnerabilities in applications.

Risk Posed by Injection Attacks

Injection attacks can cause data loss, data corruption, security breaches, and possibly the loss of control of the target host and the release of sensitive information linked to the host. A “successful” injection can also let attackers access the database without permission. This lets the attackers look at tables, get important information from them, change them, and even gain access as an administrator.

In 2007, cybercriminals used a security flaw called an SQL injection to get into 7-Eleven’s servers. They were able to get their hands on credit card numbers, which they then used to send money to themselves.

Injection Attack Types

Although they are not the only injection attacks, SQL injection (SQLi) and cross-site scripting (XSS) are by far the most common types. The following are some examples of distinct kinds of injection attacks:

1) SQL Injection (SQLi)

SQL injection is a weakness in web security that could let an attacker change the SQL queries that are run on the database. This can be used to get sensitive information like the structure of the database, its tables, columns, and data set. SQL injections are always on the CWE Top 25 list of vulnerabilities because they are one of the most dangerous flaws that can affect web applications.

An SQL injection attack is carried out when a hostile hacker inserts a SQL statement into data that is placed into a web form, comment field, query string, or any other input channel that is available to people on the outside. Malicious code usually takes the form of an SQL query that tries to get sensitive information. However, it might also take the form of a SQL statement that is intended to change the content of the database, going as far as to delete database tables.

How SQLi Attacks Work

If the target application is vulnerable to SQL injection, it will send this data to the database without checking to ensure it is safe first. After that, instead of saving a comment or getting account information, the database server will run malicious SQL queries that the attacker has put into the system. Attackers may still be able to uncover information using blind SQL injection even if the susceptible application does not explicitly reveal data.

SQL injections are one of the oldest and most deadly types of vulnerabilities that may affect online applications. SQL injection comes in at number three on the Common Weakness Enumeration’s (CWE) Top 25 for 2022. SQL injection is included in the Common Weakness Enumeration as CWE-89: Improper Neutralization of Special Elements Utilized in a SQL Command.

2) Cross Site Scripting Attacks (XSS)

Cross-site scripting, also known as XSS, lets an attacker take control of how users interact with an application that is vulnerable to it. An attacker can get around the “same origin” rule, which is meant to keep different websites from talking to each other. Cross-site scripting creates security holes that allow an attacker to take the place of a victim user, do anything the user is able to do, and access any of the user’s data. If the user who is being attacked has privileged access inside the program, the attacker may be able to take full control of the data and functions of the application.

How XSS Attacks Work

Cross-site scripting is done by making changes to a website that can be attacked so that it sends harmful JavaScript back to users. When the malicious code is run in the browser of a victim, an attacker can completely change how the victim uses the application.

XSS comes in at number two on the Common Weakness Enumeration’s (CWE) Top 25 for 2022. XSS is included in the Common Weakness Enumeration as CWE-79: Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’).

3) OS Command Injection Attack

If a program has a flaw called OS Command Injection, which is also known as shell injection, an attacker can run any commands they want on the server of an active application. The instructions that were triggered by the attacker are executed by the operating system with the help of the web server’s permissions. Attackers can use privilege escalation and other vulnerabilities to take advantage of these command injection flaws.

How OS Command Injection Attacks Work

The first step of an attack is for threat actors to find a flaw in an application that lets them run unapproved operating system commands. Next, the attacker comes up with a command that, when run by the program, will make the host operating system do what the attacker wants. In most cases, they will inject this instruction into the program via an input method such as HTTP parameters, cookies, or form fields.. After this, attackers are able to run certain commands on the host machine and start attacking the network from the infected system.
Command Injection comes in at number six and seventeen on the Common Weakness Enumeration’s (CWE) Top 25 for the year 2022. OS Command Injection is included in the Common Weakness Enumeration as CWE-78: Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’) and CWE-77: Improper Neutralization of Special Elements used in a Command (‘Command Injection’).

4) Code Injection Attacks

An application has a code injection vulnerability if an attacker can present application code as user input and convince the server to execute it. For example, if the vulnerable application was written in PHP, attackers could inject PHP code into the web server. The PHP interpreter on the web server would then read the code and run it.

Note that code injection is distinct from OS command injection since you are injecting application code rather than system commands (although one can lead to the other if your application accepts malicious code that calls a system command). This is a significant vulnerability because if the attacker is successful in obtaining remote code execution, the target system can be regarded as compromised.

How Code Injection Attacks Work

Code is frequently injected using the language of the application that is being attacked. Following that, the server-side interpreter will carry out the execution for that language. Python, Java, Perl, Ruby, and PHP are the usual suspects when it comes to languages. Most of the time, code can be injected into applications that evaluate input right away without first checking it.

Code Injection comes in at number twenty-five on the Common Weakness Enumeration’s (CWE) Top 25 for the year 2022. OS Command Injection is included in the Common Weakness Enumeration as CWE-94: Improper Control of Generation of Code (‘Code Injection’).

6) Server-Side Template Injection (SSTI) Attack

When a malicious payload is injected into a template using the template language’s native syntax, and the template is then run on the server, it is known as a server-side template injection.

Web pages can be generated using template engines by fusing together preexisting templates with dynamic data. When user input is appended to a template rather than handed in as data, a server-side template injection attack can occur. This makes it possible for attackers to insert arbitrary template directives and wreak havoc on the template engine, sometimes even taking full control of the server.

How SSTI Attacks Work

SSTI weaknesses are identified less frequently than Cross-Site Scripting (XSS) issues, for example, due to the fact that SSTI flaws are less well-known and are harder to identify.

7) HTTP Header Injection

The host header of a website or web application specifies which website or web application should be responsible for handling an incoming HTTP request. The content of this header is evaluated by the web server before it forwards the request to the website or online application that has been specified. If the attacker delivers an arbitrary host to the real virtual host, this might result in web cache poisoning as well as the execution of illegal activities like resetting a password.

How HTTP Header Injection Attacks Work

HTTP header injection and CRLF injection vulnerabilities stem from trusting user input. If a web app uses external data in HTTP replies, an HTTP header injection attack is conceivable. Imagine your company migrated to a new domain, and you want user bookmarks to work. Example.com is now example.info. If a visitor reaches an outdated URL like http://www.example.com/page1, you want the webserver to redirect them to http://www.example.info/page1.

Build a small web app at example.com that adds http://www.example.info/ to the HTTP request route. If the developer of the application doesn’t remove CR and LF from the input data before adding it to the new base URL, an attacker can use this to launch HTTP header injection attacks. In order to validate any and all user inputs on your web application, you will need to construct an allow-list.

8) LDAP Injection Attack

The protocol used to access and manage directory services on IP servers is called Lightweight Active Directory Protocol, or LDAP for short. The Lightweight Directory Access Protocol (LDAP) is a client-server protocol that is used to verify users, manage resources, and set permissions. It also gives access to a directory database. When an attacker adds harmful statements to a query, the server receives malicious LDAP queries, which can affect the security of the system. If an attacker is successful in injecting malicious code into LDAP, not only will the attacker have access to data that should not be seen, but the attacker will also be able to manipulate the structure of LDAP.

How LDAP Injection Attacks Work

LDAP injection attacks utilize unfiltered user input. LDAP injections make faulty requests to modify directory data. LDAP queries use asterisks, brackets, ampersands, and quotations. These characters affect LDAP query meaning, object type, and number. By altering the query’s control characters, attackers can change its functionality. With metacharacters, an attacker can skip over the password field in an LDAP login query.

With LDAP injection, an attacker can get unauthorized access to a directory or change LDAP statements and data. Web applications that construct LDAP statements based on user input can be exploited. Red Hat Directory Server and Active Directory use LDAP.

How to Prevent Injection Attacks

To stop injection attacks, you need to write safe code into your web application so that it can’t be easily changed. You can protect yourself from attacks in many different ways, and the right one will depend on the kind of environment you operate in. Below are some good techniques to follow:

Validate User Inputs

Injection attacks frequently focus on user inputs as important indications.

Limit Access to Essential Privileges

An attacker’s ability to damage your network depends on their access. You can limit their access by not always allowing admin capabilities on database-connecting platforms. For most tasks, use a limited-access account. If a hacker obtains access, they can only do so much.

Keep Sensitive Information Secure

Without web application credentials, attackers can accomplish nothing. Be aware of what’s presented on your system. A harmless-looking error message might provide an attacker a way into your system. Make sure web app messages don’t contain important information.

Control Who Accesses Your System

When an injection attack is caught early enough, before the attacker has full control of your system, it is easiest to stop the attack and stop any more damage from happening. The best way to find injection flaws that could be used by hackers is to install an automated online vulnerability scanner on your network. You have the option of performing the detection manually through the use of penetration testing; however, doing so will require more effort as well as more time and resources.

Avoid Injection Attacks with GuardRails

You may get started with the support of the materials and approaches that are given in this blog, but if you want more assistance, GuardRails is able to provide it. GuardRails is a platform for continuously checking the security of an application. It offers full protection from the source code to the cloud. GuardRails has the capacity to stop a vulnerability from ever taking place in the first place. If you are interested in finding out more, please do not hesitate to arrange a free 15-minute demo over at GuardRails.io.