Default configurations in software are not always the most secure. For example, you might buy a network-attached home security camera from your friendly neighborhood electronics store. While these are handy to keep an eye on your property from the comfort of your phone, they also typically come shipped with a default username and password. And since they are connected to the web, they can be accessed from anywhere. Attackers know this, and Internet of Things (IoT) devices like this are common targets for malware that hijack devices using default passwords, making them part of huge DDoS botnets like Mirai.
The same can be said about the default settings of modern CMS. While the WordPress core is generally considered secure (and certainly more secure than a web-attached security camera by default) there are some improvements that can be made to harden WordPress further against attacks.
WordPress comes shipped with some default configurations (mostly related to the wp-admin panel) which need to be adjusted for improved security. While lots of attention is given to mass-infections resulting from severe vulnerabilities, the everyday compromises affecting WordPress sites (often stemming from unprotected wp-admin panels in particular) receive less airtime. And while WordPress has improved its security considerably over the years, some issues primarily related to limiting access control remain present.
In this post we will review some of the default configurations which can contribute to these infections and what you can do as a WordPress website owner to improve your security posture, keep attackers at bay, and protect your website from malware.
Convenience vs. security
Security can be a nuisance. Keeping track of countless login details across your ever-expanding catalogue of online accounts can contribute to “password fatigue” for example.
Generally speaking, what tends to be convenient tends to be insecure — and what tends to be secure is often inconvenient. The password “pass123” is easy and convenient to remember but trivial to guess and compromise. Sadly, security and convenience are often directly opposed to one another, with gains in one often resulting in losses for the other. Much effort has been invested into bridging this gap – for example the introduction of password managers, but this has resulted in brand new security issues; for example the LastPass compromise of 2022, stemming from the newly introduced issue of a “single point of failure”.
Similarly, we can say the same for WordPress and the default configurations that it comes shipped with. It’s fair to say that the meteoric rise in popularity that WordPress has had on the web over the last 20 years is in no small part due to its ease of use, accessibility and convenience. If you want to quickly get a website up and running for your blog, small business or hobby there’s no better alternative than WordPress. However, this convenience comes at a cost – not having to jump through hoops and bend over backwards just to login to your wp-admin administration panel also means that attackers don’t have to either.
Much like any out-of-the-box software the issues can be addressed. WordPress has an exceedingly rich repository of plugins which allow us to configure the baseline installation into something which is perhaps a little more cumbersome to use day-to-day but much more resilient to withstanding attacks from threat actors.
Let’s explore some of these default configurations, why they are problematic, and ways that we can address them to improve security and ensure that your website is not “low-hanging fruit” for attackers to compromise.
Unprotected admin panels
If you go to any random website running WordPress and navigate to the /wp-admin URL, this is usually what you see:
This is, of course, a prompt to enter in the administrator username and password, and in an out-of-the-box WordPress installation this is the only thing standing between your website and threat actors.
Ideally, this login prompt should not be publicly accessible at all, and restricted only to allowed IP addresses, or hidden behind a non-standard URL. However, this same WordPress login page is used not only by administrators but also by other user roles like subscribers, customers, and editors, so the usage of robust passwords is a must.
Unfortunately, the fact that the wp-admin panel is out in the open like this renders it vulnerable to brute force attacks. Moreover, the fact that the administrator URL (wp-admin) is identical for all out-of-the-box WordPress websites is itself problematic: No probing, guessing, or investigating is required for the attackers to know exactly where to start their attack.
By default, WordPress also does not come shipped with additional login security such as two factor authentication, so additional measures to secure this page are highly recommended to have the most secure website possible.
In earlier versions of WordPress a fresh installation would automatically generate the default administrator user with the name “admin“. This was particularly problematic with respect to brute force attacks because the attackers didn’t even have to obtain a list of administrator user names. This has since been fixed, and administrators are now required to specify a custom admin name during the installation process.
However, you might think to yourself, “Well, now that that’s fixed nobody is going to know what my admin account is named, so why is this a risk? Wouldn’t they have to figure that out too?”
Unfortunately, it is very easy to obtain the list of admin user names from a default WordPress website.
User enumeration attacks
Default WordPress installations are vulnerable to what is called a “user enumeration attack“. This essentially allows anybody to coax WordPress into spitting out the admin users on a website. This is due to the existence of permalinks — essentially the ability to list posts and pages, specifically from certain authors. This stems from the origins of WordPress being primarily a blogging platform, and the convenience of being able to share content across websites.
The way it works is actually quite simple. WordPress allows you to navigate to the posts of a particular author like so:
https://example.com/author/nameHowever, rather crucially, WordPress also allows us to do the same thing but by specifying their user identification number. Instead, all we must do is navigate to the following:
https://example.com/?author=1With the number in question being the user ID of the administrator user. This will spit out a page of all posts published by the user in question. What this also does is tell you the user name used to log into the WordPress environment.
With the assistance of some handy-dandy tools such as WPScan this becomes much easier! Here is an example output of the following command:
wpscan --url example.com --enumerate uAs we can see below, this coaxes the primary admin user out of the website.
If we were an attacker at this point we would have all the information we need to begin a brute force attack.
This is not an attempt to scare users, but simply a reminder of the importance of using strong passwords and multi-factor authentication to prevent login compromise, which should stop any brute force or website-takeover through wp-admin in its tracks.
No limit to failed login attempts
Speaking of brute force attacks, this brings us to our next problematic default configuration: Lack of restriction on the number of failed login attempts. Out-of-the-box WordPress contains no limit or restrictions on the number of incorrect login attempts that can be made.
Compare this with the popular mobile operating system iOS: At six failed logins you get locked out for one minute, seven for five, eight for fifteen, and ten for an hour. This graduated approach to discouraging brute force attempts is of course not perfect but it is sufficient to deter or at least significantly slow down the most egregious attempts at breaking in. The fact is that multiple failed authentication attempts in a row tends to indicate that someone is trying to break in, and measures need to be put in place to deter that.
Coupling all of this with a universal administration URL and publicly accessible login panel this creates a perfect environment for abuse.
Direct editing of files
Although for the most part it would already be considered game over once an attacker has breached your admin panel there are more issues at play here and more trouble that attackers can cause after this point.
Another glaring issue with a default, out-of-the-box WordPress website is the ability to edit files directly on the server. This is done via the “Theme File Editor” or “Plugin File Editor” from wp-admin.
When you navigate to Tools → Theme/Plugin File Editor, admin users are granted the capability of editing the actual PHP code within their themes or plugins. See the example below of how easy it is to place a backdoor on the website from this interface:
This way, even once a compromise is discovered and the admin’s password is changed by the website owner the attackers will still have access to the environment (they also frequently add malicious administrator users).
Another favorite tactic of the attackers is to (mis)use the wp-file-manager plugin in order to upload bogus/malicious plugins or themes containing backdoors, spam doorways and other malicious content:
In fact, not a single day goes by that I do not see this exact plugin present on a compromised WordPress environment.
Put your best foot forward and prioritize website security
Website owners don’t often think of or prioritize security until it’s too late and, frankly, I can’t really blame them. Very few people start building a website with the intention of dealing with threat actors. People want to be left alone with their sites so they can blog, discuss their hobbies, listen to their music, sell their wares, manage their businesses and everything else that people have websites for. But, once a compromise happens and their website gets blocklisted by Google all of a sudden security becomes the most important thing in the world overnight.
Having a good security posture from day one is the best antidote for such situations, and starting with a secure configuration from the get-go is going to go a long way in ensuring that you won’t have to deal with a nasty (and expensive!) website compromise down the road.
A shifting landscape
The web is a very different place today than it was 20 years ago. WordPress was just getting started, everybody knew Tom from MySpace, and your parents hadn’t yet joined Facebook so it was still a cool place to hang out with your friends.
From a security standpoint, threat actors were not nearly as sophisticated as they are today, nor as well organized. Attacks tended to focus more on notoriety rather than financial gain, and the tools that were available were primitive when compared to what is used today. In today’s web, organized criminal enterprises use top-of-the-line exploit kits to compromise eCommerce websites, steal credit card details en masse and sell them on the black market; most of those victim websites in recent years run WordPress.
CMS platforms have had to keep pace with the ever-evolving threat landscape. For example, after having had an entire family of malware named after its eCommerce platform, Adobe implemented a few changes to out-of-the-box Magento websites: 2FA is enabled by default, the URL to access the admin dashboard is randomized and different for every website, and other enhanced protections such as improved protection against SQL injections and clickjacking have been implemented.
Similarly, WordPress has also implemented some improvements over the years for which its developers deserve credit. For example, automatic updates were implemented for those users who opt-in to it, there has been a push to encourage the use of robust passwords, and user role definitions have been enhanced to encourage least-privileged access. However, in its steadfast dedication to ease-of-use and convenience (arguably the keys to its overwhelming success), the issues with limiting access control outlined above in this post remain ever-present. This renders the platform stubbornly susceptible to chronic brute force attacks and the security issues which follow.
What to do next?
Fortunately there are solutions to all of the problems that I listed above. By utilizing the rich open-source repository of WordPress plugins there is a solution to every issue described in this article. These are all outlined in a previous blog post on WordPress hardening.
Remember, every security improvement can sometimes cause a corresponding decrease in convenience. Every website is different so you’ll need to consider carefully what the best balance between the two is for your situation. If you have a small blog, you may be content with enabling automatic updates and putting some strict limits on failed login attempts. On the other hand, if you run a successful WooCommerce store and handle sensitive information like payment data you may want to have some more skookum measures in place.
If you would like some help securing your website, you can also consider placing your site behind our website firewall service. Creating robust access control rules on your site is just a few clicks away!
Samuel Odendaal
Northon Torga
Pilar Garcia![Malware comes in many different varieties. Analyst Krasimir Konov is on this month’s Sucuri Sit-Down to help keep them all straight. From malicious iframes to SEO spam, join host Justin Channell as he racks Krasimir’s brain on all the different types of malware. Also, Krasimir discusses his recent blog post about a malicious cURL downloader, and Justin breaks down the latest website security news, including patched plugins you should update. Podcast Transcript Justin Channell: Hello, and welcome to the Sucuri Sit Down. I'm your host, Justin Channell, and this is a monthly podcast about website security, where we get in-depth with the malware removal experts here at Sucuri. Later in the show, I'll have our analyst Krasimir Konov to chat about some different types of malware, but first, let's take a look at other topics we've published on our blog and Sucuri labs notes this month. First up, we have some new information about credit card skimming with hackers using a hybrid method to steal payment information from eCommerce websites. Our analyst Dennis Sinegubko wrote about this for the Sucuri blog back at the beginning of June. Now, most credit card stealing malware is a client side JavaScript that grabs data and sends it to a third party server. But, that approach has a drawback for bad actors because it's still possible to track the requests and catch them as being suspicious. Now, to get around that, bad actors have started harvesting information server side by modifying core PHP files. In this case, the infection would be undetectable from the outside, but it's still going to be pretty easy to find because you're rarely modifying any of those core files, so any of those changes that are going to come up are going to be suspicious. To get around both of these drawbacks, we're seeing bad actors combine the two. So client side snippets of JavaScript are sending stolen credit card data to server side scripts that they've installed on the same server as the site. Now, this allows bad actors to cover their tracks a little bit because the traffic that's being redirected is going to the same server, and that's less likely to be flagged as suspicious. It's a bit more complicated to pull this off, but our team has been seeing this hybrid approach in the wild, so it's something to be on the lookout for. Now, another month has passed, and we found more cross site scripting attacks targeting WordPress plugins. Most notably, we discovered one that affects users of the YITH WooCommerce Ajax Product Filter plugin. Now, this is a plugin that allows WooCommerce stores to be filtered by product type, and it's pretty popular. It's got about 100,000 users right now, so with it being vulnerable, it's very important that all of them update to the latest version, which is 3.11.1. Some of the other plugins we found cross site scripting vulnerabilities with included Elementor Page Builder, Careerfy, JobSearch, and Newspaper. If you're looking for a full list of vulnerabilities that have been patched this month, John Castro at the Sucuri Labs blog has you covered. Check out our show notes for the link. Also, this month I had a blog go up detailing what's called a jibberish hack. It's basically the same motivation as an SEO spam attack where bad actors use your site's good standing to redirect visitors to their own sites. But in this attack, you'll find a bunch of randomly named folders filled with a ton of HTML files with really nonsensical file names like cheap-cool-hairstyles-photos.html. It's just going to be a mishmash of keywords that clearly you didn't put there. Unfortunately, just deleting all those HTML files and folders is not going to be enough to get rid of that jibberish hack though. You're going to need to fully clean any hacked files and database tables, and then you're going to have to deal with all the damage caused to your site's standing. And just keep in mind, if you find anything about that process too daunting, we're always here to help. Now, for this month's Sit Down, we have Sucuri analyst Krasimir Konov. Earlier in June, he had written a lab's note about a malicious downloader script that used the curl function, and we chatted a bit about it, but more importantly, we went really in-depth on all the different varieties of malware that website owners need to be aware of. But, before I get started with Krasimir, I just wanted to remind you about the Sucuri Sync-Up, our sister podcast. It's a weekly website security news briefing that you can find anywhere you get your podcasts, as well as the video version on our social media feed, and now you can even get it on your Amazon Alexa smart speakers. Just search Amazon skills for Sucuri Sync-Up, add the flash briefing, and get new content delivered every Monday. Now, on with the show. Hi Krasimir, thanks for joining us on the show. I thought we could start off and maybe have you tell us a little bit about yourself and what you do here at Sucuri? Krasimir Konov: Yeah, sure. Well, I joined Sucuri originally in 2014, but I've been in the IT business for about 10 years. Nine of those I did security. And currently at Sucuri I'm one of the malware analysts. I used to work in the front lines, used to clean websites and whatnot, and then I gradually moved up, and now I'm working in the malware research department. And my day to day job is basically analyzing malware, and then once I analyze it and figure out what it is, then I will create a signature for it. And we'll add those signatures to our tools, so we can automate some of the work we do. And I also write some Labs Notes blog posts. Usually, if I find something interesting in malware or some security topic, I'll write about it. Justin Channell: Yeah. And of those topics recently that you wrote about, one was about a malicious curl downloader, and how exactly did that work? Krasimir Konov: Right, yeah. That was an interesting one, but not very unique or anything like that. We see that a lot with curl being used as a downloader. It's a very common malware. So rather than including the actual malware in the file, the attackers would use curl to download the malicious code. In this case, they'll download it from Pastebin, but it could be anything. It could be another website or anything like that, and curl would just make a call to the website, request the code. The website will respond with the code, and then later on, there is some code to either save the output somewhere on the website, or you'll just run it through eval and execute the actual code right away. Justin Channell: Right. And you said that it's commonly found in malware, but let's kind of maybe talk a bit broader about malware in general. What is everything that is classified as malware? Krasimir Konov: Well, in general it will be anything that the owner of the website didn't authorize, anything that was added by a third party. There is a lot of different malware. It could be even something like a defacement that will also be considered malware because it was something the user did not authorize. Even though it might not be doing anything malicious on the website, it's not infecting users, the visit is still something they did not authorize. So defacement would also be considered malware. And even something like ransomware where the website is technically not really damaged, it's all encrypted, but it's not infecting anybody. It's not doing anything malicious, but it's still encrypting the entire website and asking the user or the customer, the owner of the website for a ransom they need to pay in order to get the website back online. Justin Channell: Okay. Let's maybe break it down to each individual type of malware. For example, what would be a way that maybe I-frames could be maliciously used by a hacker? Krasimir Konov: Yeah. An I-frame can be used maliciously when it loads content from another location. You can look at the I-frame as a window that just opens another website. So anything that website has on it, you're pretty much loading it through the I-frame. So if that website is infected and it's serving some kind of malware, by opening an I-frame, you're loading all those elements, everything that was on this website. And sometimes the I-frame can be as small as pixel or something hidden somewhere off the screen, so you wouldn't even know that it was opening it. Justin Channell: And yeah, I feel like we've also seen a lot of them where they're used almost to mimic popups as well. Krasimir Konov: Yeah. I mean the I-frame, it could just load from another website and the other website could do anything. It could be serving just malware and it would try to infect the user that doesn't even know that they're being connected to the other website. It could just have some other JavaScript that's just trying to open up pop ups on the original website through the I-frame. Yeah, it could be a lot of things. Justin Channell: Okay. And also, let's talk a little bit about conditional redirects and how those work. What allows a script to detect which devices are coming in and where they're coming from? Krasimir Konov: Right. Yeah. That's a common one we see a lot. Basically, a conditional redirect would be something, it's a redirect on the website. It's obviously malicious, but there's certain conditions that need to be met before the redirect is actually executed or the redirect happens. For example, let's say if it's on a phishing website or a phishing page that is hidden somewhere on the website. For example, if Google visits it, obviously the attacker doesn't want Google to see the actual phishing page and record it as a phishing page. So they'll look for, for example, the IP address. They would look for the user agent. And a lot of times they can tell that it's a bot. So they'll just return a 404 response, for example, that will be like, "Oh, page not found." So Google would be like, "Oh, it looks like this page doesn't exist." But then if a regular user goes to the same page, then those conditions will be met. The actual website or the script behind the phishing will check and see, and be like, "Oh, this one is running Firefox or Chrome," and be like, okay. And then they'll look at the IP and be like, "Oh, he's in whatever, he's in United States somewhere." And he's like, "Oh, okay. That's good." And then once all of these conditions are met, then the actual script will serve them the actual phishing page. And it'll be like, "Oh, you need to fill out this to recover your account or whatever, or type in your credentials to log in here." Justin Channell: And so this is the type of thing we're really, a website owner is going to run into this more commonly when people are complaining about they're getting served bad content or whatever, and they can't seem to replicate it. It's likely probably these kind of redirects. Is that right? Krasimir Konov: Right, right. It could be something as specific as, for example, a range of IP addresses that correspond to an ISP or maybe let's say a country. It could be like, "Oh, were targeting only customers in the US," so if you're connecting from another country and you go to the same website or the same page, it would just say 404. It will give you a page not found. But then if you actually have an IP address from the United States, you're connecting from the United States, then it will actually show you the phishing page. Justin Channell: Now another type of malware I feel like we see a lot here is SEO spam. We hear people talking about that. What are some of the top SEO spam keywords that you see coming through? Krasimir Konov: Yeah. We get that a lot. We see a lot of spam on websites. A lot of times attackers will use SEO spam to gain ranking for their own website. Or they'll just try to include some kind of SEO spam in links to another website that they're currently running or something. I mean, these things change all the time. So a website might be up for a week and then it'll disappear, and then they'll start another campaign. But yeah, we see that a lot. We see all kinds of keywords they use. Most common ones will be something like Viagra. We'll have like jerseys for sale. A lot of times, they'll use name brands like Nike, Rolex, Prada. We've seen even some essay writing services for some reason. I'm not sure why, but that's common. We see, for example, pharmaceuticals a lot that will use specific medicine names. They'll use all kinds of replicas, like a replica bag of this, replica this, replica that. We'd see prescription, also payday loans. And obviously there's some adult related sites and things like that keywords. Justin Channell: So pretty much anything that people are going to be searching and clicking on are probably going to be targets for SEO spam? Krasimir Konov: Right. I think a lot of it commonly is pharma related because a lot of people are looking to buy medicine online, and a lot of times will require a prescription. So a lot of people are like, "Oh, let me see if I can find this medicine that I can buy it online somewhere." They don't need a prescription. They don't want to pay to visit a doctor and whatnot, and they'll look for it. And yeah. Justin Channell: Now, whenever somebody's website does get hacked with a SEO spam attack, what kind of effect can it have on the website beyond just being defaced? Krasimir Konov: Yeah. You can have a lot of things can happen, negative things. For example, the website can be blacklisted because of the keywords. And that usually represents a big red warning when you go on the website, depending on who blacklisted it. But if it's Google, for example, you'll see a big warning and it'll tell you this website contains malware or there's something wrong with this website. So, pretty much all the traffic on the website will be gone. And then you can also lose a lot of your reputation if there is a SEO spam on the website. For example, if you were ranked in say number five for certain keywords that represent your product on Google search engines, and then suddenly you get hit with SEO spam, then all these search engines then go and visit the website. And all of a sudden they're like, "Oh, there's all these weird key words on here, all this SEO spam that's causing a lot of mixed signals." And the search engines are like, "Oh, where do we rank this website now? Do we rank them with this product that's originally what the website is about? Or do we take into consideration all these other keywords that are mixed up that are SEO spam?" So, all of a sudden your website might go from being ranked number five on the first page to being on the 10th page. And then you rank for all these other keywords that you didn't intend to. And then people search for something completely different. They're searching for jerseys or something, or now they're searching for Prada products, and then suddenly your website pops up in there. So you're not really getting any good traffic, not targeted traffic. But, yeah. Justin Channell: Okay. So in a lot of ways, the effects of SEO spam would kind of be the same for defacements or any kind of malware with the blacklisting, but it does bring that kind of unique part to it where then it can also then bring traffic that you weren't expecting from somebody searching for jerseys, for example. I had not really ever thought about that. Krasimir Konov: Right, right. Yeah. It will definitely bring some traffic. I've seen a lot of times where websites will be connected. Let's say, there was 1,000 websites that were all infected with SEO spam, and it will kind of link each other to try to bring each other up into the rankings. And so you would see a lot of strange traffic from some random websites that were, for example, that were previously infected, even if they might not be anymore. But yeah, they'll be sending traffic to you or there'll be usually search engines sending you traffic, but for the wrong keywords. People are looking for something else, so obviously they're not going to be interested in your website. They're not going to buy anything because they're not looking for that. Justin Channell: And now, so thinking of the way websites get infected, a very common way it seems to be is through phishing campaigns. What are some recommendations you have for the best ways to avoid becoming a phishing victim? Krasimir Konov: Yeah. There is some ways. I mean, it depends really on the type of attack. Obviously, a lot of people, when they think of phishing, they think, "Oh, it's just like a PayPal phishing page and it just looks like the original," but it could be more subtle. If it's just a regular page where you're just going and you get redirected to another website, obviously the first thing to look is if you have the security padlocks, make sure that traffic is encrypted. A lot of these websites don't really have any encryption nowadays. More are starting to get that with pre SSLs being issued and whatnot. But that's the first thing to look and see, make sure. Anywhere you're typing your sensitive information, you want to make sure you have the padlock to make sure everything is encrypted. Krasimir Konov: But also you want to look at the URL of the actual website you're visiting. A lot of times they'll try to hide it. So you might have to be careful and look closely. Something that might be an I will be an L or something like that. And a capital I and L might look kind of similar into your IRL, so you might miss something like that. Say, if you're looking for PayPal and it might replace the L with an I, and if you don't look closely, it might look exactly the same. And you're like, "Oh, okay, it's paypal.com," but not really. So yeah. Just pay attention to the URL, make sure it is the actual website. There's no paypal.com dot something, dot something else, dot com. Yeah. You want it to just say paypal.com, and then it'll have forward slash and something else. But yeah, it gets more complicated when you have, for example, a phishing page that's injected into a regular page. For example, you have a checkout page on a website that you're buying things from and you go through the checkout page and you're looking at where you type in your credit card information and whatnot. And you might have a phishing page that actually looks exactly like a little box that gives you where you put in your credit card number, or your name, your address, and all that. So that will be more subtle. For example, that could be also an I-frame that's just coming from another page. And it will look exactly like it's part of the website. You're on the legitimate website, but only that portion of the website is actually the phishing page. And you look at it and you're like, "Oh, okay. It looks fine. I'm just putting my credentials." So that one could be a lot harder to figure it out. Usually, if it's something like that, I look for something that looks kind of out of place. Maybe they didn't get the right font. It might not be the same as the original website or there might be something out of place, some fields that are missing or some fields that are squished into the left or the right. It looks kind of awkward. It's like, why would this be like this? The whole website looks professional. There's a pink background or something, for example, and then suddenly there's this white box in the middle. It's like, ah, it looks kind of weird, out of place. Justin Channell: So pretty much if anything looks slightly out of place, you really should double check everything at that point. Krasimir Konov: Right. Right. Yeah. Obviously there's more ways that you can check, but I wouldn't get into more technical, like inspecting elements and looking at stuff, but yeah. Justin Channell: And now another type of malware that's kind of, and it kind of plays in with whatever the other infection is, is backdoors. Can you give us some examples of what backdoors can be? It's mainly just when a hacker can get back into the site to reinfect it, but I know there are a ton of different methods. And what are some of the more common ones and then maybe some that really interesting that you've seen? Krasimir Konov: Yeah, there is a lot. They'll probably be one of the first things the hacker would do is if they compromise a website, obviously they'll try to spread backdoors and just inject code everywhere so they can get back in, even if the owner of the website or webmaster cleans it. They want to try and hide some malicious code somewhere so they can always get back in. There's many variations. A backdoor could be something as simple as a single line of code to just [inaudible 00:20:19] argument, some kind of string or something via get or post. Krasimir Konov: And then it runs into an eval, so it evaluates the code and executes it. And some backdoors are very complex and they can be included in, let's say you have a WordPress site and you have a specific login page where all the login credentials are being processed and everything else. They could even inject code into that to basically bypass the whole login mechanism so that they can just bypass everything. They don't even have to know any user. They don't have to know the password, nothing. They'll just include some lines in there, and every time they'll be just able to log in. Yeah. It gets pretty crazy. Yeah. I mean, there's all kinds of malware. There is always a malware, for example, that just targets credit cards and will just target the eCommerce websites. And they'll just try to steal the login credentials, I mean, the credit cards. They'll try to get your address, your credit card information, any kind of CVV code or whatever you typed into the billing address, everything. And then there's also malware like the backdoors that are just trying to keep the attacker in control and trying to get them back into the website. There's just so many variations of what a malicious user might want to do on a website. Some can be something as simple as just reinfecting the website. They don't want to keep control. They just want to keep reinfecting it with some kind of malware. So even if you clean it, it would just get reinfected. Some of them in the database, otherwise might be in the files. We've seen some added into a [inaudible 00:22:14] job that just keeps running on the server. There could be malware that is just a giant to, for example, attack out of websites. Like for example, a distributed denial service where they put the same malware on thousands of websites. And then they try to send traffic to one website to try to bring it down. Yeah. People try to do all kinds of stuff with websites. We've seen even some cryptocurrency mining malware that you go onto a website and suddenly your PC starts running like crazy. And you're like, what the hell is going on? Your fans turn on and the PC is 100% CPU. And it turns out that the website has some malware that's just by mining Bitcoins with your CPU and it's using all of it. Justin Channell: Wow. Okay. So one question now, the last question I have is of all the malware that you've seen, what do you think is the coolest piece of malware that you've ever seen? Krasimir Konov: I think the coolest would be the ones that are so subtle that you don't even know that it's there. For example, we've seen some that were pretty innovative. It will be just a one liner code that's just one line. And for example, it will be let's say 40-50 characters, something like that. And that's all it is. And they'll hide it somewhere in between the legitimate code. And if you don't know what you're looking for, you would never see it. It doesn't look suspicious. There is no links to some other website. There's no some kind of encrypted code or anything like that. It's just a simple one line. And then if you're just scrolling through the file looking for something, you would never see it. It just looks like all the other code. And then if you look closely, you're like, "Oh, there's this..." Look closely, and you're like, "Oh wow, this is not supposed to be there." And then you keep looking at it and you're like, "This looks really weird." And then you see that it's actually doing some malicious things and trying to evaluate some code or taking output from the outside, I mean, some input from outside, you can call it and give it code to run. Justin Channell: Well, Krasimir, thanks for coming on and talking to us for today. Krasimir Konov: Yeah. Thank you. Thank you. I'm so happy. I'm glad I was able to do this podcast and I can't wait to do another one. Justin Channell: Yeah, we'll have you on again. Thanks. Krasimir Konov: Thank you. Justin Channell: Thanks again to Krasimir for joining us here on the Sit Down. We'll be back with another episode next month. So be sure to subscribe on Apple podcasts, Spotify, Stitcher, or any podcasting platform. Also, be sure to follow us on social media at Sucuri Security and check us out at sucuri.net. That's S-U-C-U-R-I.net. I'm Justin Channell, And this has been the Sucuri Sit Down. Stay safe out there.](https://blog.sucuri.net/wp-content/uploads/2020/05/20-sucuri-podcast-blog-post_blog_image-390x183.jpg)
Justin Channell
Daniel Cid
Ben Martin
John Castro
Marc-Alexandre Montpas
