When we think about website malware, visible infection symptoms most often come to mind: unwanted ads or pop-ups, redirects to third party sites, or spam keywords in search results. However, in some cases these very symptoms are the results of hacktools, a diverse and often insidious category of software designed to exploit vulnerabilities and compromise website security.
In 2022 alone, a staggering 23.63% of infected client websites were found to have at least one hack tool at the point of infection, highlighting the importance of being aware of (and protecting your site from) different types of malware.
In today’s post, we’ll explore the mysterious world of hacktools, uncover their purpose, delve into the reasons they are left behind on hacked websites, examine the risks they pose to both website owners and visitors, and learn the steps you can take to detect and protect against them.
Contents:
- What is a hacktool?
- Types of hacktools
- Examples of hacktools
- Threats posed by hacktools
- How to check your site for malware
- Prevention techniques
What is a hacktool?
At its core, a hacktool is a software application or script designed to exploit vulnerabilities and gain unauthorized access to computer systems, networks, websites, or assist hackers perform a specific illicit related task. These tools are often created by skilled programmers and hackers, who share a deep understanding of the intricacies of various systems and the potential weaknesses that can be exploited.
Types of hacktools
While there are numerous hacktools in existence, some of the most common types our research team find on hacked websites include:
| Exploit kits | These kits are collections of exploits targeting multiple vulnerabilities in popular software applications, such as browsers, plugins, and content management systems. They are often used as part of automated attacks, scanning websites for known vulnerabilities and delivering payloads when a suitable target is found. |
| Web shells | Web shells are scripts that provide attackers with remote access to a compromised website or server. They often come with a user-friendly interface, allowing attackers to execute commands, upload or download files, manage the server with ease and can be tailored to specific needs or ends that the hacker chooses. Sucuri classifies most web shells as backdoors. |
| Brute force tools | Brute force tools are designed to systematically guess usernames and passwords, attempting to gain unauthorized access to accounts and systems. They often come with pre-built dictionaries of commonly used passwords and can be customized to target specific services, such as email or content management systems. |
| Confidential information stealers | As the name suggests, these tools are designed to steal sensitive information, such as login credentials or credit card details, from targeted systems. This can be accomplished through various means, including keylogging, phishing attacks, or exploiting known vulnerabilities in software applications. |
| DDoS tools | Distributed denial of service (DDoS) tools are used to overwhelm a target website or server with a massive amount of traffic, rendering it inaccessible to legitimate users. These tools often leverage botnets – networks of infected computers – to amplify the attack and make it more difficult to trace back to the source. |
| Mailers | Mailers are hacktools that let an attacker send out large amounts of malspam or phishing emails from a compromised website’s web server. It contains various text fields that allow the attacker to input custom data for email fields like email address, sender name, reply-to, subject lines, and body content. |
While not all hacktools are created equal, they are typically used to target and exploit target websites. And they’re often packed with a range of features that make it easy for an attacker to compromise an environment and exploit any available resources.
Examples of hacktools
Here are some examples of hacktools that we find on compromised websites.
Spam mailers
Spam mailers that we find in website environments tend to be PHP scripts which are designed to automatically send out emails. When placed on compromised websites, the mailer scripts hijack the mail server functionality of the server and blast out spam emails to users whose email addresses have been made publicly accessible and landed them on a spam list.
Database management
It’s not uncommon for attackers to hide their payload or other components of their malware within the database of a hacked website. In order to do so they need some way to interact with and otherwise manage the database. While database management tools are perfectly legitimate and used frequently by website administrators, they can also be used by attackers, particularly if such scripts are left unattended in the docroot of websites. The most popular such tool is Adminer: Used for both legitimate and illegitimate purposes.
Mail testers
Before blasting out spam emails from a compromised website/server, attackers will want to ensure that mail sending is actually working before they go about their business. One such way they do this is by uploading a mail tester script onto the server, which tests common email functionality to ensure that it is working on the server before they start sending out their spam or phishing emails.
Admin hider
Another favourite among attackers is the admin hider. These are commonly located within the functions.php file of the active theme on the website. When an attacker creates a new administrator user within the CMS installation such as WordPress it’s not uncommon for them to hide it from view of the legitimate website administrator. This is accomplished by concealing a user with a particular name, reducing the visible admin user count by 1, or other clever tricks to hide their user from view.
Why do attackers leave a hacktool on a website?
To better comprehend the threats posed by hacktools, let’s examine five key reasons why attackers choose to leave these tools on hacked websites.
Malware propagation
Hacktools often serve as a means for attackers to spread malware to other systems, both within the target network and beyond. By leaving these tools behind, they can use the compromised website as a distribution platform for their malware campaigns, whether it’s discovering other sites that can be infected on the same server, searching for resources that can be abused (ie. mail servers or databases), or using the website as a stepping stone to infiltrate other networks.
Monetize illegal activities
The presence of hacktools on a compromised website can be indicative of an attacker’s intent to profit from illegal activities, such as spamming, phishing, or distributing denial of service attacks. By leveraging the website’s resources and reputation, attackers can potentially generate revenue from their illicit actions, all while remaining hidden behind the cloak of the hacked site.
Espionage and data theft
Hacktools can be instrumental in facilitating cyber espionage and data theft. Attackers who manage to infiltrate a target website or server may use these tools to exfiltrate sensitive information, such as customer data, intellectual property, or trade secrets. In some cases, this information can be used for financial gain, while in others, it may serve as a means of exerting control or inflicting damage on the target organization.
Threats posed by hacktools
The presence of hacktools on a website poses a significant risk to both website owners and their visitors. One of the most immediate concerns is the compromise of website security, leading to unauthorized access and potential data breaches. This can result in the loss of sensitive information, such as customer data, which can have severe legal and financial repercussions for the website owner.
- Blacklisting: Hacktools can cause domain and server IP blacklisting due to spamming, brute force attacks, or DDoS assaults. This can result in legitimate emails being blocked by spam filters, and certain APIs may cease to function as firewalls block requests from the affected IP address.
- Mass compromise: These tools enable mass compromises of sites sharing the same server. A hacktool exploiting flaws in server configurations on an unrelated third-party site could infect an otherwise secure website.
- Increased resource usage: Hacktools can increase resource usage, placing a strain on the CPU or generating large amounts of traffic. This can slow down the site and server, deplete quotas, and potentially incur additional costs for cloud platforms that charge based on resource usage.
- Indicator of compromise: The presence of a hacktool is an indication of a compromised site. In addition to hacktools, compromised sites often contain other types of malware, including SEO spam and visitor-targeted malware like unwanted redirects and drive-by downloads.
Moreover, the reputation and trust built by the website owner can be severely damaged, as hacktools can potentially disrupt website functionality and user experience, further deterring visitors and tarnishing your site’s credibility.
How to check your site for hacktools
Detecting hacktools on your website is a crucial step in maintaining a secure and trustworthy online presence. To effectively identify and neutralize these threats, follow these steps.
1 – Perform regular website security scans
You’ll want to perform regular, extensive scans of your website’s files to identify vulnerabilities and rule out a compromise or infection.
You can leverage free tools like SiteCheck to scan your website for malicious code, but keep in mind that remote scans won’t be able to detect anything lurking on the server level.
You can complement external scans with server-side scans, which can help identify hidden hacktools or other malicious files within your website’s infrastructure.
2 – Check your domain and server IP against known blacklists
You can easily check an IP against a list of known blacklists by leveraging free scans found in Sucuri SiteCheck, Spamhaus, and AbuseIPDB.
SiteCheck
Sucuri’s own SiteCheck makes it easy to check a domain for malware, viruses, blacklisting status, and other malicious code. It checks domains against a wide number of blocklist authorities to identify if it’s engaged in any known sketchy behavior.
To scan a website, navigate to https://sitecheck.sucuri.net then enter a domain and click Submit.
Spamhaus
Spamhaus is an international nonprofit organization that has been combating spam and cyber threats like phishing, malware, and botnets since its inception in London in 1998. Spamhaus operates DNS-based blocklists responsible for blocking a significant portion of spam and malware on the internet.
Checking an IP or domain with this tool is easy. Simply navigate to https://check.spamhaus.org/ then enter the IP or domain URL into the search box and press Lookup.
AbuseIPDB
AbuseIPdb.com is an excellent resource that allows you to check if an IP has been reported for abusive activities like hacking, spamming, or other malicious behavior.
To scan your server IP, navigate to abuseipdb.com and enter your IP into the search box to query for known malicious behavior.
3 – Monitor your website’s logs
Regularly reviewing your server and website activity logs can help you detect unusual or suspicious behavior, such as repeated login attempts, unauthorized file uploads, or unexpected changes to website content.
By catching anomalies and unexpected behavior early, you can take appropriate action to mitigate potential threats on your website.
4 – Use file integrity monitoring
Implementing a file integrity monitoring system can help you detect unauthorized changes to your website’s files, which may indicate the presence of hacktools or other forms of compromise.
These systems typically work by comparing the current state of your files to a known, trusted baseline, alerting you to any discrepancies.
If you’re a WordPress user, you can leverage the Sucuri Security WordPress plugin which contains tools to check the integrity of your core WordPress files, including PHP, JavaScript, and CSS.
5 – Leverage intrusion detection systems (IDS)
Intrusion detection systems (IDS) can help identify and block potential threats before they can cause damage to your website. These tools monitor your network for signs of malicious activity and can be configured to automatically respond to threats, such as by blocking IP addresses or quarantining affected files.
The Sucuri Firewall bundles the best of a WAF (Web Application Firewall) and an IDS (Intrusion Detection System) to detect and protect against website threats and attacks.
6 – Analyze your website traffic for unusual patterns
Monitoring your website traffic for unusual patterns or spikes can help identify potential hacktool-related activity, such as DDoS attacks or SEO spam campaigns. By recognizing these abnormalities, you can take swift action to investigate and address the issue, minimizing the impact on your website and its users.
How to prevent infection from hacktools and other malware
Protecting your website from hacktool infections requires a proactive and comprehensive approach to security. Here are some best practices to help you protect your site from hackers.
- Regularly update your website software and plugins: Keep your website software, plugins, and other components up-to-date to minimize potential vulnerabilities that could be exploited by hackers. Ensure that you apply security patches and updates as soon as they become available to reduce the risk of compromise.
- Employ strong and unique passwords: Use strong and unique passwords for all of your website accounts, including your content management system, hosting provider, and any other administrative access points. Avoid using easily guessable passwords or reusing the same password across multiple accounts.
- Implement multi-factor authentication: Enhance the security of your website by implementing multi-factor authentication (MFA) for your accounts. MFA requires users to provide additional proof of identity, such as a temporary code sent to a mobile device, in addition to their password, making it more difficult for unauthorized users to gain access.
- Limit user permissions and access: Restrict the number of users with administrative access to your website and assign the minimum necessary permissions to each user. This reduces the risk of unauthorized access through compromised accounts and helps to prevent the misuse of privileged access.
- Use a web application firewall: A web application firewall (WAF) adds another layer of security to your website by filtering and monitoring inbound and outbound traffic. A WAF can help detect and block malicious requests, such as SQL injection or cross-site scripting (XSS) attacks, before they reach your website. By using a combination of predefined rules and customizable settings, a WAF can be tailored to your specific security needs, providing an effective barrier against hacktools and other cyber threats.
Conclusion
Understanding and recognizing the threats posed by hacktools is a critical aspect of securing your website and protecting your visitors. By taking proactive measures to prevent, detect, and respond to malware-related incidents, you can minimize the potential impact and provide a safer online experience for your users.
If you believe your website has been infected by hacktools or other malware, don’t hesitate to chat with our website security specialists. We offer quick and thorough website malware removal to help restore your site and harden it against future attacks.
Ashley Sand
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Pilar Garcia
Matt Morrow![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
Rianna MacLeod
Luke Leal
Allison Bondi