Ad Violations: Why Search Engines Won’t Display Your Site If it’s Infected With Malware

As your site’s webmaster, have you ever seen an e-mail from Google like this:

Hello,

We wanted to alert you that one of your sites violates our advertising policies. Therefore, we won’t be able to run any of your ads that link to that site, and any new ads pointing to that site will also be disapproved.

Here’s what you can do to fix your site and hopefully get your ad running again:

1. Make the necessary changes to your site that currently violates our policies:
Display URL: site.com
Policy issue: Malware
Details & instructions:

2. Resubmit your site to us, following the instructions in the link above….

If so, you know the potential downside risk this poses for your website. In their own words, Google says,

In some cases, you may be unaware that you have malware on your site. But to protect the safety and security of our users, we stop all ads pointing to sites where we find malware.

In essence, Google and Bing care about their searchers more than your business so, to protect their customers, they’ll shut your website out of Adwords and Bing Ads and will return your site less in organic searches.

Often overlooked in the search business is the role of the actual search engine in the ad placement process. These are businesses that specialize in creating algorithms to show relevant search results, assigning quality scores to your landing pages and placing your actual ads. A lot goes into the process, but in all cases, the key for the search engine is to show relevant search results (including ads) that keep people using their search engine. It is in this spirit that search engines like Google and Bing reserve the right to refuse your ads. This is especially true if they have any reason to believe that your site may be infected with malware–including viruses, worms, spyware, and Trojan Horses–or is being used in phishing schemes.

From the search engine’s perspective, this makes perfect sense. Searches are their lifeblood and there are other search engines a person could use to find websites. By showing your ads or returning your site organically in a search, they are tacitly telling the searcher, “We found these sites to be relevant to you.” If they start sending you to sites that are potentially harmful, then a searcher could, potentially, switch search engines.

However, knowing why search engines work as they do doesn’t make it easier to be a webmaster when a site is hacked. Luckily, our clean up and malware removal tools as well as our de-blacklisting service are just a click away.

Or, better yet, keep yourself from ever getting an email like the one above from Bing or Google. Instead, protect your site, and business, from potential problems stemming from malware, blacklisting or phishing and look into protecting your site with a website application firewall like our CloudProxy WAF .

PHP Backdoors: Hidden With Clever Use of Extract Function

When a site gets compromised, one thing we know for sure is that attackers love to leave malware that allows them access back to the site; this type of malware is called a backdoor. This type of malware was named this because it allows for remote control of a compromised website in a way that bypasses appropriate authentication methods. You can update your site, change passwords, along with any of your admin procedures, and the backdoor would still be there allowing unexpected access to an attacker.

Backdoors are also very hard to find because they don’t have to be linked in the site, they can be very small and be easily confused with “normal” code. Some of them have passwords, some are heavily encrypted/encoded and can be anywhere on your site, file system or database.

We have written extensively about website backdoors (generally in PHP) that allow for continuous reinfections and control of hacked websites.

You can read something more about backdoors on these links:


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Darkleech + Bitly.com = Insightful Statistics

This post is about how hackers abuse popular web services, and how this helps security researchers obtain interesting statistics about malware attacks.

We, at Sucuri, work with infected websites every day. While we see some particular infections on one site or on multiple sites, we can’t accurately tell how many more sites out there are infected, and how many people were exposed to that malware. All we can do is estimate.

Most estimations are based on data that can’t provide the whole picture such as number of detections in our SiteCheck scanner, number of cleanup requests, number of posts about a particular problem in webmaster forums. This only helps to tell whether it’s something “major” or “minor”.

Like any other firm out there, sometimes we can make some good educated estimates. For example, we can target specific Google searches that reveal the number of sites that contain some text, or URL specific to a particular attack. Another example is if an attack uses one specific URL (or a few well known URLs), then Google Safe Browsing reports also help estimate number of infected sites. These Google-based approaches are more precise, but they don’t work for most attacks that frequently change domains and have no artifacts that can be found in search results.

If security researchers are quite lucky, they might find an attacker’s unprotected (or poorly protected) Control Panel that contains all the statistics about infected site, clicks, exploits, etc.

This post will be about a different and quite unusual way of obtaining data about activity of a server-level attack that is known for being hard to detect and track.


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Understanding Google’s Blacklist – Cleaning Your Hacked Website and Removing From Blacklist

Today we found an interesting case where Google was blacklisting a client’s site but not sharing the reason why. The fact they were sharing very little info should not be new, but what we found as we dove a little deeper should be. The idea is to provide you webmasters with the required insight to understand what is going on, and how to troubleshoot things when your website is blacklisted.

Get Your Bearing

While investigating the website, we found that some Google shortened URLs were being loaded and redirecting to http://bls.pw/. Two of the goo.gl links were pointing to Wikipedia images, their icon to be specific, and one was redirecting to http://bls.pw/ shortener.

goo.gl/9yBTe - http://bits.wikimedia.org/favicon/wikipedia.ico
goo.gl/hNVXP - http://bits.wikimedia.org/favicon/wikipedia.ico?2x2
goo.gl/24vi1 - http://bls.pw/

A quick search for this last URL took us to /wp-content/themes/Site’sTheme/css/iefix.sct. As malware writers like to do, it was trying to trick us into believing it was good code. In this case, the Sizzle CSS Selector Engine code (Real code here) was the target:

Sucuri  Sizzle CSS Selector Engine Modified III

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vBulletin.com Compromised

The vBulletin team recently announced that they suffered a compromise which allowed the attackers access to vbulletin.com servers and database. On their own words:

We take your security and privacy very seriously. Very recently, our security team discovered sophisticated attacks on our network, involving the illegal access of forum user information, possibly including your password. Our investigation currently indicates that the attackers accessed customer IDs and encrypted passwords on our systems. We have taken the precaution of resetting your account password. We apologize for any inconvenience this has caused but felt that it was necessary to help protect you and your account.


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Case Study: Analyzing a WordPress Attack – Dissecting the webr00t cgi shell – Part I

November 1st started like any other day on the web. Billions of requests were being shot virtually between servers in safe and not so safe attempts to access information. After months of waiting, finally one of those not so safe request hit one of our honeypots.

We won’t get into the location of the site because it really doesn’t matter, a fact that most critics don’t realize. As is often the case, the honeypot site was quiet without much traffic and the weakness was access control.

We intentionally left the password to the site to one of the top 10 passwords, with continuous attempts it took about 3 months before it was accessed.

This time though we were ready and this is how it went..

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Blackhat SEO and ASP Sites

It’s all too easy to scream and holler at PHP based websites and the various malware variants associate with the technology, but perhaps we’re a bit too biased.

Here is a quick post on ASP variant. Thought we’d give you Microsoft types some love too.

Today we found this nice BlackHat SEO attack:

Sucuri SiteCheck ASP Malware

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Joomla – Fancy SPAM Injections

Malware writers can be really ingenious when it comes to obfuscating their code. And let’s face it, in today’s anti-malware push, they have to; the slightest variation will often trigger warnings that will make it look suspicious in turn shortening its life-span.

When we talk about obfuscation the first thing we think is base64 encoding, gzinflate or any other built-in function that will help making the code illegible for the average user, but they’ll often stick out to the trained eye.

With that in mind, obfuscating the malware code to look like good code is the best approach to make it last longer.

Take this code, for example:

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Backdoor Evasion Using Encrypted Content

A few weeks ago on the Sucuri Research Labs we mentioned a new type of malware injection that does not use base64_decode, and instead conceals itself as a variable and is built with a combination of “base_” + (32*2) + “_decode”. This is the part of the code where it is hidden:

$g___g_='base'.(32*2).'_de'.'code';

Any tool that looks for eval, followed by base64_decode, or just flags on any base64_decode usage, will not find it.

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Avira, AVG and WhatsApp Defaced

If you visited the web sites for Avira, AVG or WhatsApp this morning, you probably saw that they didn’t look like they should. All of them were defaced and looked like this:

02 avira defaced

It is a bit horrifying when you see such big sites, including security sites from major Anti Virus products (like AVG and Avira) getting compromised. But what really happened? Did they really get hacked?

DNS redirection

In a broader sense, they did get hacked, but not through a compromise on their servers or network. It looks like the attackers got access to their domains registration panels at Network Solutions and modified their name servers.

For example, these were the new name servers for Avira:

$ host -t NS avira.com
avira.com name server ns1.radioum.com.br.
avira.com name server n1.ezmail.com.br.
avira.com name server n2.ezmail.com.br.
avira.com name server ns2.radioum.com.br.

And these new names servers were pointing Avira’s IP address to 173.193.136.42, instead of the real IP address. That’s why visitors to the site were greeted with a defacement page.

What causes a bit of suspicion is that all these domains are hosted at Network Solutions, so we have to wait a bit more to see if it was caused by a breach on their end or something else.

Update: Avira posted the following on their tech blog: “It appears that our account used to manage the DNS records registered at Network Solutions has received a fake password-reset request which was honoured by the provider. Using the new credentials the cybercriminals have been able to change the entries to point to their DNS servers.” So it doesn’t looks like Netsol was directly hacked, but the attackers found a way to reset the passwords for certain accounts.