The Structured Query Language, or SQL for short, is an incredibly effective tool for managing the data utilized by your site or application. In case you missed it, we created this quick introduction to SQL just a few weeks back. While this language is of extreme importance to many webmasters, it can also become a tremendous threat. Major consumer-facing sites, such as Microsoft, LinkedIn and even Yahoo have all been breached by SQL injections. Even the CIA has fallen victim. But what does this actually mean?
What is an SQL Injection?
SQL injections are actually fairly simple. The easiest way to explain these injections is to say that they are actually just malicious code posing as legitimate user data. In doing so, the injection is able to wreak havoc on an entire database. One of the most common ways hackers use SQL injections is by infecting user authentication data by corrupting the data as when it is input into the database.
Damage Done by SQL Injections
As with any web-based intrusion, there are several areas of concern with respect to SQL injections. The obvious threat here is that the data in the database may be stolen, altered, corrupted or even destroyed. While data integrity is always of the utmost concern, it is worth noting that if an SQL injection is strong enough, it can take down an entire network. This sort of attack generally happens as a form of DoS (Denial of Service) activity.
What You Can Do to Prevent SQL Injection Attacks
In terms of protecting your server from an SQL injection, nothing beats regular data hygiene. Data sanitation, for example, involves executing test functions against select sets of data to ensure the integrity of the data being tested. These exercises should be happening regularly!
Data validation is also critical here. This is simply the practice of setting up criteria to define parameters for how you expect to receive your data. One common example of this sort of validation test would be ensuring that all email addresses contain both an “@” sign as well as a real domain, such as “gmail.com”. While these simple practices go a long way towards protecting the data on your server, many hackers are able to get around them. Sometimes, additional steps are needed to mitigate your risk of an SQL injection.
7 Advanced Techniques for Securing Your Server
1. One best practice when using SQL is to avoid using dynamic SQL if at all possible. That’s because dynamic SQL is an easy target for intruders.
2. Encrypt your passwords. Any confidential information should always be encrypted and appropriate permissions levels should be set to offer the greatest level of protection to your server against SQL injections.
3. Change your passwords regularly. This is just a good practice for all aspects your web activity, but the data integrity of your server is one area where this piece of common sense security advice need not go unheeded.
4. Failure to remove unnecessary data or database functionality can easily result in a SQL injection. This unused data, which is probably not closely supervised, can quickly become an easy target for hackers.
5. Use discretion when crafting error messages. It’s important not to provide too much information here. That’s because any information you provide can potentially be used by hackers. Keeping error messages short and vague and even crafting them in code is a great way to keep your risk of an SQL injection in check.
6. Web Application Firewalls (WAF) can be an effective way to keep malicious SQL out of your database. Of course, a firewall is only as good as its configuration allows it to be, so some work is still required by the webmaster.
7. Making sure to apply all patches may seem like a no-brainer, but failure to do so in a timely manner may expose your server or database to vulnerabilities unnecessarily.
What Happens if Your Database Becomes Infected
In the unfortunate event that your database is compromised, the first step to resolving the issue is to find the vulnerability. In most cases, the issue will have crept in through unpatched holes in outdated software, so it’s important to update immediately if you haven’t already done so.
If this is not the case, you should contact your hosting provider. A backup can be loaded to take your server to the state it was in before the injection occurred, and as long as you were able to identify the vulnerability you have a fresh opportunity to correct it. The problem with this is that A: not all hosts provide adequate backups and B: you will lose all changes made on your server between the prior backup and the time of the backup.
This is one situation where many users could benefit from going with a managed VPS provider. At SemoWeb, we’re happy to help our clients through thick and thin. To find out more about securing your server or to speak with one of our Systems Experts, take advantage of the LiveChat feature on our site.