Today, Injection attacks are a significant problem and top the list of vulnerabilities. There are good reasons for this. They are dangerous. Injection attacks exploit various vulnerabilities to deliver untrusted user input, which is then executed by the web application. This is why they are a threat to the web application industry.
Using the injection method, an attacker can inject different types of programs. The input is interpreted, so the operating system perceives it as a command and executes it. This leads to incorrect results and corrupted data and executes malicious code, and runs viruses from under a regular, legitimate application. This way, an intruder can get sensitive data that he should not get. Because this method is the oldest, most attackers use it.
Before we take a closer look at popular types of injection attacks, let’s find out what injection attacks are? The term “injection” can reflect the method of cyber security attack. Just as injecting liquid medication enters the body, in an attack on a computer attackers transmit some data to retrieve information. This injection comes mostly from threat actors whose goal is to cause harm and steal data or even cipher the files.
✅ Code Injection
This is a typical injection attack. Suppose the attacker knows the programming language, the web application, the database operating system, etc. In that case, it is easy to inject the code through text input and pass it to the web server. Code injection targets applications that lack input validation.
The user can type anything, so the application becomes potentially vulnerable. A hacker can inject malicious code, and the server will let him do it. Injection code vulnerabilities are not hard to find; you need to provide different content, then the attacker will put it into the same web application. If the hacker exploits the vulnerabilities, confidentiality, availability, integrity, etc., may be lost.
✅ SQL Injection
This is a similar type of injection, but here the attacker attacks SQL scripts. SQL is the language used when executing queries in a given text entry field. Such a script needs to get into an application that will directly perform operations on the database. The hacker also needs to pass the login screen, and sometimes he needs to do even more dangerous things to read sensitive data from the database. This also means that the attacker has to perform the action again. PHP and ASP applications are more vulnerable, so the chances of a successful SQL injection attack are higher. J2EE and ASP.Net are more immune to this attack, but still not invincible. You can’t even imagine how limited the attacker’s skills and imagination are.
✅ Command Injection
This type of attack is reasonably expected if sufficient validation is not implemented. Instead of programming code or script, attackers insert a command into the system. The hacker may not know the programming language in some cases but can quickly identify the server operating system. There are several inserted systems in which the operating system executes commands, thereby allowing content exposed by arbitrary files residing on the server. Compared to others, it also shows the directory structure to change the user’s password. To reduce these types of cyber attacks, a sysadmin should limit the level of access to the system where web applications can run the server.
✅ Cross-site Scripting
When something is inserted, the output is automatically generated without coding or verification. This allows an attacker the ability to send malicious code to another end user. In this application, attackers have the ability to inject malicious scripts into a trusted website. As a result, that site becomes a victim of the attackers.
Without noticing anything, the victim’s browser starts executing the malicious script. In doing so, the browser gains access to session tokens, sensitive information, cookies, etc. Such XSS attacks fall into two categories – stored and reflected. In stored, malicious scripts target the server through a message forum or visitor log. In this case, the victim also receives a browser request from the message forum. In the reflected XSS, the malicious script gives a response that sends input data to the server. It can also be an error message from the server.
✅ XPath Injection
Like SQL Injection, XPath Injection attacks occur when a Website uses user-provided information to create an XPath query for XML data. By sending deliberately corrupted information to the website, the hacker can learn the XML data structure or gain access to data he shouldn’t have access to. A hacker can even elevate his privileges on a website if XML data is used for authentication (e.g., an XML-based user file).
XPath is a standard language that allows you to specify attributes wherever you find them. It is used to query XML data and other web applications that specify data, and they must match. When you get the malformed input, this temporal pattern will turn into an operation so that an attacker can apply the data.
✅ Mail Command Injection
This application includes IMAP or SMTP assertions that incorrectly verify data entered by the user. As a result, they have no robust protection against attacks, and most web servers can be exploitable. Once attackers have entered through email, they bypass captcha restrictions and restricted request numbers. They need a valid email account to be able to send messages to inject commands. Typically, these injections can be made in a webmail application that can exploit the message reading functionality.
✅ CRLF Injection
The suitable combination of CRLF is a carriage return and line feed. It is a web form representing a method of attack. It has many traditional Internet protocols such as HTTP, NNTP or MIME. This attack is often based on a vulnerable web application and it does not do the right filtering for the user point. Here, the vulnerability helps open a web application that does not do proper filtering.
✅ Host Header Injection
There are many websites or applications on this server where there is a need to identify a resident website or web application. Everyone has a virtual host that handles an incoming request. So, the server acts as a virtual host that can send the request. If the server receives an invalid host header, it usually gets past the first virtual host. Typically, attackers use this vulnerability to send arbitrary host headers. While host header manipulation is directly related to the PHP application, other web development technologies also do it. Host header attacks work similarly to other types of attacks, such as web cache poisoning, and the consequences also include all kinds of things attackers do, such as resetting passwords.
✅ LDAP Injection
This is probably one of the best protocol designs that make it easy to work with another network. This is a useful intranet where you can use a single-sign-on system, and the username and password will be stored here. But it is important to remember that there is also more danger from the different types of password attacks. This LDAP request involves a special control character that affects its management. An attacker can change the intended behavior of LDAP, which can control this symbol. It can also have several root problems that allow an LDAP injection attack that is improperly verified. The user sends text to the application that the LDAP request is part of, and it arrives without being sanitized.
✅ XXE Injection
This type of embedding provides a vulnerability when compiling an external XML object (XXE). It used support where it provided a DTD with weak XML parser security. An attacker could easily use the created XML documents to execute various attacks where it would have remote code execution from path traversal to SSRF. Like the other four attacks, it did not use unverified user input and is inherently insecure. The only way to avoid the vulnerability that disables DTD support is to process the application in XML documents.
Preventing Injection Attacks
Almost all of the injection attacks listed above are based on the execution of unreliable input by the web application. Not surprisingly, improper input validation is ranked #4 on the CE Top 25 list. Careful cleaning, filtering, and coding of all user-controlled input can help prevent the vast majority of injection-related vulnerabilities.
It is also critical that developers know and use the secure input handling mechanisms that modern web frameworks and languages provide. For example, SQL injections are easily prevented with parameterized queries or prepared server-side statements (aka stored procedures). And in frameworks such as React, writing code that is vulnerable to XSS is only possible by intentionally bypassing the built-in protections.
All attacks are performed directly on the server and everything related to open access to the Internet. To prevent these attacks, you need to update it with advanced applications and regular updates released by the respective software vendors. Likewise, to minimize the possibility of attacks on frequently changing applications and new attack methods, it is recommended to regularly and automatically test all web applications and APIs with application security testing solutions integrated directly into the development lifecycle.