Cyber threats are on the rise and SQL Injection is a troublesome hacking method that compromises the cybersecurity of digital assets. It's a strategy that attackers use to introduce malicious code into data-driven applications. Once inside, this rogue code can become a major headache for developers and users. Hackers can access sensitive information and even destroy entire databases. It's a serious threat that every developer and business owner should be aware of and take steps to prevent.
A certified cybersecurity course helps students know about potential cyber threats like SQL injection attacks and build cybersecurity proficiencies. In this article, we will get to know what SQL injection is, how harmful it is, and its types. We will also find out about some effective SQL injection attack prevention tips in this article.
What is SQL Injection?
SQL injection, or SQLI for short, is a prevalent attack method that mischievously inserts harmful SQL code into backend databases. SQL Injection enables attackers to infiltrate databases and lay hands on sensitive data. With the successful infiltration of this code, hackers get access to database records, and can alter, update, add or wipe out data permanently.
You might be wondering what its goal is. Well, its goal is to access information that wasn't meant to be shared with others. This information could be anything from confidential company data to private customer details, putting businesses and users at risk. SQL codes are like digital trespassers who sneak into users’ databases and mess up important files without permission.
A successful SQL injection attack can ruin websites or web apps reliant on relational databases like MySQL, Oracle, or SQL Server. Recent times have witnessed numerous security breaches stemming from such SQL injection attacks, which highlights the urgent need for robust defenses against this security threat.
The repercussions of an SQL injection on a business are extensive. A successful breach could lead to unauthorised access to user lists, the wholesale deletion of tables, and, in some instances, the attacker can even acquire administrative control over a database. These outcomes are disastrous for any business and pose significant threats to its operations and reputation.
How Does SQL Work on A Website?
A typical website comprises three key elements: the frontend, backend, and database. The frontend, where the website's design is crafted, utilises technologies like HTML, CSS, and JavaScript.
In the backend, programming languages such as Python, PHP, or Perl are used to manage the server’s operations. The database resides on the server side and hosts systems like MySQL, Oracle, and MS SQL server, executing queries. Crucial data is stored here. Usually when users write a query, they initiate a “get” request to the website. Subsequently, the website responds by sending back HTML code.
A SQL query is like a request for something to happen in a database. It can also make changes outside the database. Each query has its own settings to make sure it only shows the right results. However, during a SQL injection, hackers incorporate malicious codes into a query’s input form.
Before launching a SQL injection attack, hackers first study the targeted database thoroughly. They do this by sending different random values to the query and noticing how the server reacts. Once they understand how the database works, they create a query that tricks the server into thinking it's a regular SQL command, and then the server runs it.
Examples of SQL Injection Attacks
Below, we have enlisted a few prevalent examples of SQL injection:
- SQL query alteration: Cybercriminals can change a SQL query to uncover hidden data, revealing sensitive information that's not supposed to be disclosed.
- Login bypass: Hackers inject SQL commands into a login form to bypass the authentication process and gain unauthorised access to programs or websites.
- Undermining application logic: Hackers can also tamper with queries to disrupt the normal operation of the application.
- Union attacks: These attacks help attackers to retrieve data from multiple database tables simultaneously.
- Database analysis: Cybercriminals study the database to learn about its version and structure, extracting valuable insights.
- Blind SQL injection: In this type of attack, no error messages are generated by the database, which makes it harder to detect the attack.
- Distributed Denial of Service (DDoS) attacks: In this type of attack, an attacker inserts a SQL statement to trigger a denial of service (DoS) or DDoS attack, disrupting a system with overwhelming traffic.
Types of SQL Injections
SQL injections generally come in three categories: In-band SQLi (classic), Inferential SQLi (blind), and Out-of-band SQLi. These types have been classified based on how they access backend data and the extent of potential damage they can cause.
In-band SQLi
In-band SQL injection involves attackers utilising the same communication channel to serve two purposes, namely, to execute their attacks and to retrieve the outcomes. This method's simplicity and effectiveness makes it one of the most prevalent types of SQL injection attacks.
There are two sub-variations within this method:
- Error-based SQL injection: In this case, attackers provoke the database to generate error messages by performing certain actions. They can then use these error messages to learn about the database's structure.
- Union-based SQL injection: On the other hand, this attack exploits the UNION SQL operator. This operator combines results from different select statements in the database, providing a single HTTP response. Attackers can use this response to access valuable data.
Inferential SQL injection
Here, attackers send specific data to the server and then analyse how the server responds. By studying these responses and the server's behavior, attackers gain insights into the database's structure. This method is termed "blind" because the attacker doesn't directly receive data from the website database, making it impossible to see information about the attack in the same channel of communication.
Blind SQL injections depend on analysing the server's response and behavior, which can make them slower to execute compared to other methods. However, they can still be just as damaging.
This type of attack can be subdivided into two types:
- Boolean: One type of Blind SQL injection is Boolean, where attackers send SQL queries to the databases, triggering the applications to produce a result. Depending on whether the query is true or false, the HTTP response will change accordingly. By observing these changes, the attacker can determine whether the query yielded a true or false result.
- Time-based: In Time-based Blind SQL injection, the attackers send SQL queries to the databases, causing it to delay its response for a set amount of time. By observing the duration of this delay, the attacker can infer whether the query is true or false. Depending on the outcome, the HTTP response will either be immediate or delayed. This allows the attacker to determine the truthfulness of the query without directly accessing data from the database.
Out-of-band SQL injection
This is another method of attack that relies on specific features being activated on the database server utilised by the web application. It serves as an alternative to in-band and inferential SQL injection techniques.
It is usually employed when the attacker cannot utilise the same communication channel to execute the attack and obtain information, or when the server's performance is too slow for these tasks. Out-of-band SQL injection relies on the server generating DNS or HTTP requests for transmitting data to the attackers.
Harmful Effects of SQL Injection Attacks on Your Business
SQL injection attacks pose significant threats to businesses or organisations, with potential negative outcomes including:
- Unauthorised or administrative access to sensitive information and resources by cybercriminals.
- Risk of data breaches due to unauthorised entry into resources.
- Manipulation of data or deletion of entire database tables by malicious actors.
- Breach of databases facilitating intrusion into entire networks or systems.
- Erosion of customer trust, potentially leading to reduced revenue.
- Substantial time and resources required for recovery and implementation of enhanced security measures.
Although the immediate impact of a successful SQL injection attack may be challenging to determine, the long-term repercussions, such as damage to reputation, legal expenses, and missed business opportunities, can be prominent.
How to Prevent SQL Attacks?
Many modern websites and applications rely on databases built with Structured Query Language (SQL). However, vulnerabilities like SQL injection (SQLi) emerge when websites fail to properly screen or control the queries they receive. Lack of proper administration enables attackers to sneak bits of SQL code into the queries, thus gaining access over valuable information from the database. Hence, preventing these attacks becomes paramount. Unlike malware, which is mostly downloaded, SQL attacks work by being injected.
Below discussed are some effective measures following which companies can prevent such dangerous attacks.
Filter database inputs
This is a crucial step in bolstering security against SQL injection vulnerabilities, even though it may not stop attacks entirely. By filtering inputs from websites and applications, organisations can lay the groundwork for a more secure environment.
However, attackers often exploit loopholes in extended URLs and special character handling to infiltrate databases and execute unauthorised commands. They can possibly gain access to sensitive data and even delete it. Businesses must also take this into account when monitoring their databases.
Restrict database code
While input filtering is an effective step, attackers can adopt various other ways to execute their intentions. They can circumvent the code through sero-day vulnerabilities or compromised credentials. Therefore, to enhance security, organisations must impose restrictions on the code that gives access to the database. By doing so, they can exercise greater control over the database's capabilities, thereby reducing the potential for exploitation by attackers.
Database managers can achieve this by minimising functionality, and making a list of fair user inputs. These measures confine the database to essential functionalities, reducing unexpected uses and potential exploits.
Restrict database access
Eventually, a user's login details might get stolen, or a hacker might find a hidden weakness in a website, database, or server. To reduce the harm caused by a SQL injection attack:
- Use firewalls to control who can access the system from outside.
- Limit what users can do by only showing them basic error messages and restricting their access to certain parts of the database.
- Make it hard for attackers to profit from a breach by encrypting sensitive data and avoiding shared accounts as much as possible.
Maintain applications and databases
Companies need to keep an eye out for any new weaknesses in their apps and databases that hackers could exploit using SQL injection. It's important to stay informed about any updates or fixes announced by the software makers. To protect against SQL injection attacks, it's essential to keep everything up to date, including the database server, frameworks, libraries, plug-ins, APIs, and web server software. If companies find it hard to stay updated, they can also invest in patch management tools available.
To make monitoring more effective, advanced tools like Privileged Access Management (PAM) and Security Incident and Event Management (SIEM) can use smart technology like machine learning and behavior analysis. These tools add extra security layers and help organisations spot possible threats early on. This also makes application-level hijacking extremely hard.
Conclusion
By now, we know how important it is for businesses to safeguard themselves against rising SQL injection attacks. By continuously monitoring SQL statements and promptly addressing existing weaknesses, they can strengthen their protection against potential breaches and data compromises.
Investing in advanced tools and techniques, such as Privileged Access Management (PAM) and Security Incident and Event Management (SIEM), further bolsters security measures. This in turn ensures the proactive detection of malicious code and the mitigation of threats. Lastly, companies must stay vigilant and alert in addressing SQL injection vulnerabilities to maintain their integrity and security
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