SweetCaptcha is a free CAPTCHA service that offers to match “sweet” images instead of making you recognize distorted digits and characters.
It has integrations with many website platforms including; pure PHP, WordPress (10,000+ plugin installs –EDIT: The plugin was taken out from the repository since this post, however, we found out that the plugin has returned to the WordPress repository under a different name: jumpple which is a discontinued WordPress security plugin). The plugin files are the same as we analyzed in this blog post. WordPress was already notified.), Drupal, Joomla, ModX, .NET, JavaScript, and even offers an API that can be used on other platforms.
So far so good.
Malicious Pop-ups
We began to receive complaints from website owners using the sweetCAPTCHA service, claiming their visitors would occasionally see pop-ups and pop-unders that promote tech support scams, dating sites with fake badges, or offer to install malicious software (drive-by-downloads).
Below is an image that would show the user a “security error” on the site and offer them a helpline to get support on the issue:
Ad script inside sweetCAPTCHA code
A quick investigation revealed that websites using the sweetCAPTCHA service normally include this JavaScript:
hxxp://www . sweetcaptcha . com/api/v2/apps/csrf/(digit_id)?ver=3.1.0
… Which loads this code:
In the middle of the code it tries to load a script from //clktag .com/adServe/banners?tid=SWTMPOP&tagid=2.
The URL is quite self-descriptive and it’s obvious that it has to do with advertising. But wait, what do CAPTCHA and banners have in common? Not much, really. And that is very suspicious.
Could it be that the sweetCAPTCHA site was compromised and hackers injected that clktag .com code into their scripts? Maybe. But there seems to be another explanation. If you read the sweetCAPTCHA Terms of Use, in the “5. Use of the Services by You” section you’ll find this:
5.2 You acknowledge that within the sweetCAPTCHA service and/or sweetCAPTCHA API, There might be included 3rd party content which will be displayed for the purpose of user interaction. This content might include but will not be limited to ads, banners, links, search engine input fields and etc.
This explains the use of an ad script in CAPTCHA and why they provide this service for free.
Malicious clktag ads:
Let’s dig a bit deeper and check if that clktag script is really the source of the nasty pop-ups.
When I opened it in a Windows sandbox, it loaded the following chain of URLs:
1. hxxp://t . mtagmonetizationc . com/build/c66fd9/v1/script/?sourceURL=012420312&cacheBuster=[cacheBuster]
2. hxxp://creative .speednetwork9 . com/speednetwork9/scripts/direct/direct.html?a=12624189&serverdomain=s.speednetwork9.com&context=c36771041&size=800×600&rt=popunder&ci=10&cb=1433844662858
3. hxxp://s . speednetwork9 . com/ul_cb/imp1822?a=12624189&context=c36771041&size=800×600&rt=popunder&ci=10&cb=1433844662858
Here we see a pop-up that “requires” us to install a Media Player HD.
If you click on Update, you’ll be redirected to the following page:
4. http://cdn . downloaddart . com/lp/?appid=1435&subid=ff7d244e9-d619-9346-7ca2c009feb49688a71a2e5783ffb0195c4bc433114001e&c8=service.quicksear.com&btp_h=5ce92a83379e88bf88172db6aeff5064
It then shows you installation instructions and automatically begins downloading the hxxp://software . softwareserver04 . com/MediaDownloader/setup.exe file.
Here is what VirusTotal thinks about this file: Detection ratio: 7 / 57 – (Trojan, PUP, Artemis)
If I load that sweetCAPTCHA script in Linux it automatically opens pages with a fake tech support scam from:
"hxxp://help .arubatechhelp .com/callflow/lp17iktyyr/?a=HT&u=...&clickid=...&ent=yes&ext=yes&rec=yes&au=yes&lo=yes......."
… and a dating site that looks like another scam:
"hxxp://www .charmdate .com/qa/internationaldating/register06.php?aid=82&oid=CP224643&qpid_offer_id=CD_226513TK".
So the answer is: Yes, the sweetCAPTCHA script is responsible for unwanted and potentially malicious popups.
Note, the ad script tracks users and in most cases, you’ll only see those nasty pop-ups when you visit a site for the first time.
Adware History of sweetCAPTCHA
The sweetCAPTCHA service has been ad-supported for a long time (check this one-year-old topic on the WordPress.org forum) but it didn’t cause a lot of problems. Just an occasional hiccup in September of 2014, when one user noticed an unwanted search bar. Back then, the SweetCAPTCHA support team gave this explanation:
SweetCaptcha is a FREE project, we had some pilots for a very short time with monetization solutions back in the past, but they were just pilots, meaning ended long time ago.
sweetCaptcha was always Free from ads and will stay so.
Apparently, around June 8, 2015 sweetCAPTCHA began another similar pilot which did not go unnoticed by site owners who use their service. Here are the recent forum posts about unwanted pop-ups:
- June 8, 2015 Sweet Captcha Injects Popup Ads
- June 9, 2015 pop-under ads come with the plugin
- June 9, 2015 Injects Spam with Malicious Code
- June 9, 2015 SweetCaptcha Injecting Pop Up Ads on Purpose
- June 9, 2015 Sweetcapcha hacked and causing malicious popups
SweetCAPTCHA is Not Alone
Using potentially unwanted third-party scripts on client sites is not a new monetization model. Some other “free” services use it too. The most known are probably Sitemeter.com — a “free” site counter that loads tons of third-party ad scripts behind the scenes. They also disclose this in their terms of use and privacy policy — but apparently, very few users read them.
Dangers of Hidden Ad Scripts
You may think that hidden ad scripts are not that bad as long as they don’t inject annoying ads and pop-ups. Well, this practice is not that benign.
First of all, the main purpose of such hidden ad scripts is to spy on web surfers. When you visit a site with a banner or hidden ad script (e.g. a site that only has a Sitemeter script) that script places a cookie on your computer. Now they know what sites you visit and can target specific ads to you.
The second issue is that it’s usually not just one third-party script. At the top level it may be just one script from a third-party domain (principal partner), however, that partner ad network usually has a few other partners and it allows them to load their own scripts on your site too. The second level partners usually have third-level partners and so on. It is quite typical to see that one ad network script initializes downloading content from dozens of third-party sites. In one extreme case that we worked on, three ad scripts resulted in requests to over a thousand third-party domains — it took several minutes to completely load a simple blog page.
The third issue is malvertising. When you allow multiple unknown third-parties to load arbitrary content on your site, the chances are one or more of them will eventually join the dark side (or just get hacked) and start serving malicious content. This is what happened quite often with sites that use the Sitemeter counter and this is now what has happened with sweetCAPTCHA-powered sites.
Summary
- If you use sweetCAPTCHA, you might want to remove it (at least for now).
- Carefully read term of services when you install something on your site – the software might include unwanted extras that they don’t advertise on their homepages.
- Think twice before installing any third-party scripts on your site. You lose control over content of your web pages. You should only install scripts that you really trust.
Allison Bondi
Luke Leal
Sucuri Malware Research Team
Ben Martin
Chase Watts
Puja Srivastava![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)
Marc Kranat
23 comments
It was a great tool for stopping unwanted spam registrations into our BP back-end. Too bad they went this route. We were one of the impacted sites and I can report that my personal PC was loaded with a Malware script as a result of one of the compromised advertiser sites. Took a full day of research because we thought our site had been compromised only to find the hidden script as you did. The other fast way to see if the script is compromised is to use the Chrome “Inspect Element” tool and browse what is loading; that was how we identified the issue.
SweetCaptcha has now been permanently removed from our system and servers.
Update – it appears that SweetCaptcha has been pulled from the WordPress plugin repository.
We have been reported same ads displaying on our few digital marketing websites. We tried a lot to find out some solutions to mitigate this problem but couldn’t. Hence only solution is to remove SweetCaptcha from your sites to make it safe.
Thank you so much for your work in uncovering this issue… and to WP Engine for working with you folks!
Yes, I’ve lived this one as well. Nice catch Denis!
Yes, this is in fact the case as of today. We have experienced this with a number of our hosting clients and have required them to deactivate and uninstall the plugin.
Thank for the notice. I just deleted sweetcaptcha and the ad-redirects seem to be gone.
The problem now is that my social share buttons which were supposed to be at the side of each post are now way at the bottom of each page. Also, I used to have a greet box at the beginning of each post which is now no longer showing. Any idea how I can fix this?
Your help is much appreciated.
How did you get rid of the pop ups ? My site is showing pop ups even after removing all files …
Confirmed. We also just deleted this plugin.
IMO this developer/website should be reported.
Great job on this. You saved me a hunt that could have cost me thousands in goose chases.
I wish I had found this posting before spending a half day reverse engineering exactly what was done here! But at least our site wasn’t hacked, which was my primary concern.
Death to these scumbags…
Thanks for the excellent research and report. I had this issue on our site and you folks ID’d it for me, thanks a lot!.. It was a great tool as the other poster stated,.,removed…
Thanks for this post! This is exactly what happened to our site and we thought we were hacked. Turns out it was just a plugin with some terms of use we didn’t read.
I can only confirm. This shit cost me a whole day to narrow it down.
Motherfucking Sweetcaptcha go to hell!
I had someone today with the latest version of the plugin getting infected so there is no fix in site? I emailed SweetCaptcha directly…. Hope they fix it soon.
Doesn’t seem to be a SweetCaptcha infection.
It’s rather an intended “feature” they added to make some money with their plugin by showing 3rd party ads on all sites that were using their plugin.
Ads/popups occur on all site pages, not just pages where captcha shows up so it looks like a hack rather than something related to that plugin.
We’ll remove all plugins from this provider.
WordPress should include a remote security mechanism on all sites, to disable plugins that become malware or generate big security risks.
Even more interesting: This plugin did NOT redirect me when I was logged into my admin account. If it hadn’t been reported from a friend, I would have never seen it happening. Way scummy, people. I bet that’s why sales were down this month. Who wants to buy from a site with malicious ads?
Thank you. Thought it was a hack. Spent days trying to track this down, even having our host scan our system. Disabling the plug-in did the trick.
Sucks when software goes evil.
I can confirm this. All the sites installed with Sweet Captcha got riddled with popup spam. All gone after removing the plugin. ‘Developers’ like this ruin the internet.
Not every popups are harmful for use.But if the started annoying us through annoying ads ,misleading popups, Misleading message and started tracking your history.Then you must take steps against these activities.My suggestion is you should use some best popup blockers.Here i am suggesting you some popup blockers by using this you will be safe from unwanted popups.you can use popup blocker pro, ablockplus popup blocker, popup blocker.Or you can search online you will find lot of popup blockers.
What do you guys recommend as a Captcha plugin for the contact form?
Until we normal people realize that Companies, Corporations, Products, and Services pay to infect your computer equipment with Malware designed to irritate the living shit out of us we can do nothing to stop it.
Why don’t we start ratting them out on social media sites and tell the world who perpetrates this costly aggravation on it’s future (and current) customers?
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