Brute force attacks against WordPress have always been very common. In fact, Brute Force attacks against any CMS these days is a common occurrence, what is always interesting however are the tools employed to make it happen.
You create a website, because it’s super easy these days, publish the content and within a few weeks people try to repeatedly log in. These login attempts come from botnets, they are automated and their goal is simple “break into as many websites as they can by guessing their passwords.” Once they find one that matches, they take over of the site and use it to distribute malware, spam and similar activities.
Here is a small example, from our own honeypots, where we see hundreds of login attempts per day, trying various combinations:
user: admin, pass: admin user: admin, pass: 123456 user: admin, pass: 123123 user: admin, pass 112233 user: admin, pass: pass123 ..
The passwords may seem silly, but after going through the most common 200/300 dictionary passwords, they can get into many web sites.
XMLRPC wp.getUsersBlogs
Originally, these brute force attacks always happened via wp-login.php attempts, lately however they are evolving and now leveraging the XMLRPC wp.getUsersBlogs method to guess as many passwords as they can. Using XMLRPC is faster and harder to detect, which explains this change of tactics. This is not to be confused with our XMLRPC being used to DDOS websites, in this instance they are leveraging it to break into websites. Be sure to read up on the differences between Brute Force and Denial of Service attacks.
This attack is being made possible because many calls in the WordPress XMLRPC implementation required a username and password. It these attacks, we are seeing wp.getUsersBlogs being used (and ocassionally wp.getComments), but it could be other calls as well. If you provide a user and a password, it will confirm whether the combination is correct or not:
<methodCall><methodName>wp.getUsersBlogs</methodName><params><param><value> <string>admin</string></value></param> <param><value><string>112233</string></value></param></params> </methodCall>
In the example above, the attackers tried the user admin with the password 112233.
Large Scale Brute Force
To examine the scale of this attack, we went back through our logs to get a better sense for the scale of the attacks. The past couple of weeks have been interesting. The attacks have increased ten-fold with almost 2 million attempts since the beginning of July coming from 17,000 different source attacking IPs. Some days we were seeing almost 200k attempts.
The only reason these numbers are not higher is because we’re killing the logs after block attempts, so all you are seeing is the gradual increase in attacks, but not the complete picture. This is what makes this entire thing very scary for website owners.
Another interesting point about this attack is the usernames being tried. Instead of relying only on “admin”, it tries to find the domain name and the real admin of the site to use it instead. These are the top user names tried:
179005 test 167147 admin 32030 sitedomain (domain modified to protect the innocent) 15850 sitedomain2 (domain modified to protect the innocent) 9590 realsiteadmin (user name modified to protect the innocent) 9564 realsiteadmin2 (user name modified ..)
So out of 2 million attempts, only 167k used the username “admin”. That shows that just disabling the admin user name, does not help if the attackers can easily find out the real user. One small reason we no longer subscribe to the argument of removing the “admin” user to be secure.
As for the passwords, they are using the most common passwords found in many dictionaries:
1dc13d admin 123123 admin1 admins 123456 12345678 7777777 letmein 121212 qweqwe iloveyou administrator holysh!t 55555 1q2w3e qwerty wordpress wpsite internet asdfghjkl 121314 lollipop killer pass lovers hello dragon admin123 office jerome fyfcnfcbz
Brute Force Protection
There are many ways to block brute force attacks. If you have a dedicated server, you can install OSSEC (open source) on it and let it automatically block the IP addresses that miss too many passwords. We automatically include brute force (password guessing) protection on our Website Firewall (CloudProxy), so if you are looking for a 1-click solution, you can leverage it.
There are obviously a number of application level tools (i.e., plugins) many will recommend within the WordPress ecosystem to help with Brute Force attacks. Here is the thing, none of the ones we tried will protect you from the XMLRPC calls, including our own plugin. It’s likely why we’re seeing the shift in attack methods. Blocking at the edge is going to be your preferred method until that gets fixed.
Juliana Lewis![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
Celise Davison
Ben Martin
Rodrigo Escobar
Gerson Ruiz
Ashley Sand
Denis Sinegubko
Victor Santoyo
63 comments
At least in my tests, adding the .htaccess text below seems to stop the attack pretty much instantly.
Can you folks verify this as as well?
Order Deny,Allow
Deny from all
That should be correct Jim. Any of the XMLRPC plugins that disable XMLRPC via Apache should stop this in it’s tracks. I’m using iThemes Security for a similar method but basically this just lets Apache keep ANYONE from getting to the file. However, it does completely make the file not accessible to pingbacks, trackbacks and connections from remote tools like Livewriter and Jetpack, which is what is making people whine. Too bad. Its better than being hacked.
Would this interfere with something like InfiniteWP, which allows you to manage sites remotely?
We use InfiniteWP and also use the Disable XML-RPC plugin and they co-exist fine. https://wordpress.org/plugins/disable-xml-rpc/
It might. I know it causes issues with JetPack, which forced us to do a more granular block on xmlrpc.
It very well might. It all depends on how they are authenticating. You’d need to send them a quick email and find out. Would you please report back and let us know what they say?
I know that it should not affect iThemes Sync and it likely does not affect WP Pipeline either, due to how these use an internal plugin on each managed site.
I use InfiniteWP and blocked the access to XMLRPC using .htaccess, no problem for infiniteWP. I guess the use something else for interactions.
Yes, IWP connects directly to the plugin in the remote site using its own API. So, no need for XML-RPC 🙂
I would also be interested to know this. I use IWP but since blocking the file, I have not noticed any issue with IWP – though would be keen to know what they say.
Nope, it doesnt interfere. But I found that no matter if you disabled XML-RPC spammer are still able to do pingbacks. To solve this, you just need to disable pingbacks in posts and pages, from the Comments screen and thru phpmyadmin:
UPDATE wp_posts SET ping_status=’closed’ WHERE post_status = ‘publish’ AND post_type = ‘page’
UPDATE wp_posts SET ping_status=’closed’ WHERE post_status = ‘publish’ AND post_type = ‘post’
This simple approach will cover the holes that currently Akismet, Conditional Captcha, Wordfence nor iThemes Security cant.
All the best and good luck with those slippy attackers.
Jim, why do you add =”” after the file name?
The extra =”” is being added by this website’s blog software.
Correct, is simply:
xmlrpc.php> and not xmlrpc.php=””>
From my experience, the resulting 404 page that this deny rule causes can still cause high load on a server because of the amount of requests being made to the xmlrpc.php page. I have seen that a better method is to simply null route the xmlrpc.php page by using the following redirect rule in the .htaccess file of the targeted site:
RewriteRule ^xmlrpc.php$ “http://0.0.0.0/” [R=301,L]
This null routing causes less server resources to be used than a 404 http response.
THIS WORKS!!!
Max,
Thank you. Null routing seems to be the best method. My sever load was tremendous prior to seeing your Solution. Simply blocking access to the file was not enough.
Max, you are my new hero!
>50% CPU processing 404s down to <0.2% with your null routing magic.
Max, what if you’re using iThemes and you Turn Off the file? How does this differ from that? By denying access all together? And if using iThemes does it write something similar to the htaccess already?
I have a client getting massively attacked everyday and I’ve thrown everything I can at this, even the kitchen sink but nothing works. It’s so bad that I can’t even reboot the server now.
I use some filters inside my .htaccess to block access to file like xmlrpc.php as well. How about this WordPress filter? add_filter( ‘xmlrpc_enabled’, ‘__return_false’ );
The XML-RPC interface can be protected depends on the user agent: https://gist.github.com/sergejmueller/0c0999871b733a7db5c1
Login Security Solution has protected against brute force attacks via XMLRPC since April 2013, and has always been the most sophisticated and comprehensive login security plugin available, in my opinion.
I will have to try it 🙂 Thanks for the tip.
Ian, my site is being bombarded by “POST /xmlrpc.php HTTP/1.1” every few minutes. Login Security Solution won’t detect these attacks. Please check your raw log and let us know if that plugin detects it on your sites.
LSS doesn’t block the requests before they hit the web server (like a firewall would), so you’ll still see the attempts in your web server logs.
What it does is flags the IP if there are multiple failed attempts, and then when more attempts are detected, it will fail the authentication attempt, disconnect the database, and leave the HTTP connection open for a random amount of time (between 4 and 30 seconds, I think). It works that way in order to drain resources from the botnets.
Well, I simplified this matter while testing LSS.
I set the failed attempt notification as ‘1’, then I logged out and logged in with not valid credentials. I got a LSS warning email immediately. But it doesn’t work to detect XMLRPC attacks, there is no notification about such attack from the servers in the Netherlands which continues month after month.
Ian, I am sorry, you are right.
I just ran a script against my site, LSS was reporting that as a XMLRPC attack. Everything is fine with LSS. I guess those bots from the Netherlands got some poorly written code and it can’t be properly connected to my site.
Thanks for your tip.
No worries, I’m glad to hear you got it sorted out 🙂
I just tested it too and it’s working for me. I didn’t test the e-mail notifications, but I can see the failed logged attempts recorded in the `login_security_solution_fail` database table, and am noticing the artificial delays that LSS introduces.
So….. DDOSing yourself then. Seriously, this is a terrible idea. If a large enough botnet exists they can actually bring you to a grinding halt by your own security protocol.
One day I woke to find my mail box full with warnings from a wordpress plugin installed which blocks ip after four failed attempts. I guess there were around 35k attempts were made. I was surprised since I have a server config which kills all POST requests to wp-login.php – http://blog.applegrew.com/2013/05/securing-the-wordpress-login-page/. Then I figured the source was xmlrpc. Disabling that solved my problem.
On my wordpress website I use a question and answer challenge as part of registration and logging in – is this defeated by the xmlrpc method? I haven’t had a spam registration since I enacted this but it hasn’t stopped the automated brute force nonsense of course.
Daniel– why won’t existing brute force plugins work against XML-RPC? XML-RPC authentication uses wp_authenticate, so any functions hooked on to authenticate filter or wp_login_failed hook should still run
Most plugins rely on hooks for the failed login (specially the wp_login_failed), which is not called on XMLRPC.
I have reviewed all of the code and tested extensively from WP 3.9.1 back to 3.0 and wp_login_failed is bring triggered every time– what’s leading you to think that it would not be called?
I ran a test and found the ‘Limit Login Attempts’ plugin works the same on XMLRPC login attempts as on the WordPress login form.
Hi Daniel,
Could you explain how “Using XMLRPC is faster and harder to be detected” ?
Daniel, as an emergency workaround, what do you think about the password-protected wp-login? Let’s say, a bot finally breaks through xmlrpc.php and sends the site credentials back to the intruder. Yet he either some other attacking script won’t be able to normally login via wp-login.php because that page is password-protected. Thanks in advance.
The actual user name of the account used to post an article appears in the RSS feed for the blog unless you’ve given the user a display name and configured WP to use the display name instead of the actual user name. I use a random character string for the default admin account on my blogs and was still getting login attempts using the correct user name.
I still recommend that the default “admin” name be changed, but don’t solely rely on that for obfuscation.
Very good point, thank you
Over the last 3 days, I have noticed a massive amount of traffic hitting
my VPS client sites xmlrpc file. At one stage there were more than 100
bots per second. This flood successfully brought down two of our busy
ecommerce sites, leading to client calls (clients don’t really know what
a DDOS is and don’t care, they just want their site to work. Though
they were patient, this kind of issue can cast a shadow on your
service).
We tried a whole range of things to try to mitigate
the issue, SYNFLOOD in our CSF firewall (no effect), Wordfence plugin
(no effect), BRUTE protect plugin (no use).
Finally we blocked
the file using
Orderbut the bots simply turned to thedeny,allow Deny from all
theme index file and continued their DOS attack.
Then we came up with a mod_sec rule which had more success:
SecRule
REQUEST_LINE "POST .*wp-login.*"
"pass,initcol:ip=%{REMOTE_ADDR},setvar:ip.maxlimit=+1,deprecatevar:ip.maxlimit=1/600,nolog,id:35011"
SecRule
IP:MAXLIMIT "@gt 10" "log,deny,id:350111,msg:'wp-bruteforce: denying
%{REMOTE_ADDR} (%{ip.maxlimit} connection attempts)'"
SecRule
REQUEST_LINE "POST .*xmlrpc.*"
"pass,initcol:ip=%{REMOTE_ADDR},setvar:ip.maxlimit=+1,deprecatevar:ip.maxlimit=1/600,nolog,id:35012"
SecRule
IP:MAXLIMIT "@gt 2" "log,deny,id:350112,msg:'wp-bruteforce-xmlrpc:
denying %{REMOTE_ADDR} (%{ip.maxlimit} connection attempts)'"
The
problem with disabling xmlrpc is that a lot of plugins and sites use it
legitimately. Removing it will break wordpress. Now I am investigating cloudflare and your cloudproxy service
If you are not using the wordpress API is there any reason not to just disable xmlrpc.php?
Seems either blocking access via htaccess or just setting the file permissions to 000 would easily eliminate this threat.
The latest WordPress update (3.91) has not mitigated this issue – I am still seeing huge DOS traffic at xmlrpc.php files across a range of sites.
There is a new brute force exploit for xmlrpc.php. Attackers are using XMLRPC API method wp.getUsersBlogs to brute force logins with dictionaries.
All *BIG* giant whitehats. Ah nice catch.
I recently received an email from my All In One WordPress Firewall and Security plugin on one of my sites informing me that someone had been locked out for too many failed login attempts. I was surprised, since I have my login pages hidden. When I looked at my raw access logs, I saw that they were using xmlrpc.php. My security plugin caught it, though. It is set to lock out anyone who uses the wrong login name after the first attempt.
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I find it interesting that the developers of wordpress have not closed the loop on this issue, this has been going on for YEARS and now its 2015 and once again there is an attack… When will they decide that the usage of this xmlrpc.php is just not a good thing, what good is it? Does Google rank your site based on pings? NO, in fact google basically does not care, so zero SEO factor, it seems like this code is dying, perhaps wordpress is not as useful as it once was.
The problem is… there are lots of widely used third party plugins and web services that make use of xmlrpc and thus, it cannot be dropped from core.
Maybe… the WP team could drop it if they develop an xmlrpc plugin to provide the same functionality. So, it would only be installed on required scenarios, but this is not a goal for now. There are more great changes to come, and until then, you can only submit it as a feature request in their forums 🙂
well failing that functionality, would it not be wise to hardcode an execution timeout?
Maybe yes. Below is the best site to post such a request:
https://github.com/Automattic/jetpack/issues
Let me know if you do it so I can second it 🙂
certainly, I just wonder why they cannot add a little user authentication before making a call to PHP
I have not had a problem, but then my wordpress blogs do not allow either outside comments or people to register in the first place, both are set to admin posting only. I’m guessing that eliminates the vast majority of the problems since there is only ONE acct and the login user name is not the same as the displayed names in posts, it’s also not “Admin” 🙂
Not granting public access by allowing people to log in eliminates that security issue.
I wrote this plugin to protect my servers, but still being able to use JetPack (which requires your xmlrpc.php to be available from JetPack’s/Automattic’s servers): https://wordpress.org/plugins/stop-xmlrpc-attack/
It will alter your .htaccess to block all requests to xmlrpc.php, except for requests originating from Automattic’s/JetPack’s IP address subnet. I polls ARIN on a regular basis to keep your .htaccess updated to any network changes…
// Maybe is not mine to say but why not edit the xmlrpc.php
// and at beginning add some ip recognition stuff like:
if (sha1($_SERVER[‘REMOTE_ADDR’]) == ‘0f9c22a8675fff9c3ad20d42e7e8579dde99477d’) {
// content of xmlrpc.php
} else {
print ‘ERROR 403’;
// or something else
}
// And for the multi user same but:
if ((one ip == sha1) || (second) || (etc.)) {}
// Just you have to know
print sha1(your ip);
// to start with…
edit: is not ‘print’ command is ‘echo’ …
Mine are being attacked this week… 🙁
Simply Use captcha
Put a double authentication via .htaccess, easy and effective.
did this. login attempts are still happening.
Username enum is coming from the guys at WPSCAN, at least thats how I enum site admins.
That’s one of the biggest issues (flaws) with WordPress as a tool for creating websites (as opposed to, say, ASP.NET) – you relegate too much control to WordPress and as a result you have little control and in most cases almost zero understanding of what’s going on – you just slap together a site using various plugins that you buy or get for free and you consider yourself a master website builder … until someone hacks into your “stronghold” and wipes out all the data.
If you’re building a website with ASP.NET such issues as you’re describing here rarely come up – you are free to implement login as you wish (including two form authentication or federated authentication (aka single sign-on)) because there are no set login pages (like the loginwp.php page) and with creating the login page and choosing the method of authentication yourself, you’re forced to learn more about securing your website via authentication and thus you’re less likely to become another victim of script kiddies.
XML-RPC server accepts POST requests only. what is the solution and plz be more clear on the explain because it hard for some person !! thanks for that …
Wouldn’t it be even better if in addition to install LSS you also installed a plug-in to rename (mask the name) of the wp-login and wp-admin files in order to make it more difficult to identify the site as a WP site or are there too many other ways to identify the site as a WP site?
We are seeing a lot of hits the past few days against /xmlrpc.php…. is there anything we should do?
I solve the problem with a free wordpress plugin ( Authentication and
xmlrpc log writer ) and enforcing on my server fail2ban. No more
problems. It also preserves the server performace killing multiple
authentications attemps on single xmlrpc call.
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