In our blog, we wrote several times about various types of Ransomware, most recently about CryptoLocker. In most cases, ransomware has pretended to be a program installed into a victim’s computer by the police. Because of some alleged suspicious activities found on the user’s computer, ransomware blocks the user from using the computer and demands a ransom to unlock the machine or files.
Different ransomware families have different graphics and skins, usually showing intimidating images of handcuffs, logos of various government and law enforcement organizations, policemen performing inspections, government officials, etc… You can read some of our previous analyses on our blog – Reveton, Lyposit, Urausy – are the most prolific examples of such ransomware.
In this blog post, we will look at the functionally of the same type of ransomware, but one which displays more annoying and disturbing photos. After showing the message saying, “Your computer has been suspended on the grounds of viewing illegal content,” accompanied with the current IP address, name of internet service provider (ISP) and the geographical location, it displays several pictures of child pornography!
In recent days, the avast! Virus Lab has observed a high activity of malware distributed through exploit kits. Most cases of infection are small websites which usually provide adult entertainment, but there was also news about one of the top 300 visited websites being infected.
Infection chains ended dropping a final payload in a form of an executable file with a constant, not wide-spread name like 1SKKKKKKK.exe. After a closer look, we found that this filename is shared among aggressive malware threats – banking Trojans like Win32:Citadel, Win32:Shylock/Caphaw, Win32:Ranbyus, Win32:Spyeye; stealthy infostealers like Win32:Neurevt (a.k.a. BetaBot), Win32:Gamarue, Win32:Cridex, Win32:Fareit; and even file infectors like Win32/64:Expiro(infected dbghlp.exe).
We received ~1000 unique samples in the last 10 days which possess suspicious filenames, polymorphically covering ~30 malware families with many different packers. Researching infected iframes in our databases, we discovered an infection chain which leads to a payload with a strange name that looks like this:
Question of the week: I have read frightening stories about CryptoLocker locking computers. I don’t have $200 to pay blackmailers for my own files. How do I protect myself from getting attacked? Does avast! protect from CryptoLocker?
“Avast! Antivirus detects all known variants of CryptoLocker thanks to our automated processing and CommunityIQ,” said Pavel Sramek, researcher and analyst for the avast! Virus Lab. “There are less than a dozen; this doesn’t seem to be a case of rapidly mutating malware.”
What is CryptoLocker?
CryptoLocker is malware known as “ransomware” that encrypts files on a victim’s Windows-based PC. This includes pictures, movie and music files, documents, and certain files on local or networked storage media. A ransom, paid via Bitcoin or MoneyPak, is demanded as payment to receive a key that unlocks the encrypted files. The victim has 72 hours to pay about $200; after that the ransom rises to over $2,200.
How to get CryptoLocker?
The CryptoLocker virus is often attached as an executable file disguised as a PDF attachment to an official-looking “spoofed” email message which claims to come from banks, UPS or FedEx claiming to be a tracking notification. When someone opens the email, they are asked to download a Zip file that contains an executable file (.exe) that unleashes the virus. There is also evidence that CryptoLocker started with infections from the ZeuS or Zbot banking Trojan and is being circulated via botnets to download and install CryptoLocker.
How to protect your computer from CryptoLocker?
AVAST users should be safe from infection during the short period when the malware is new and “undetected” as long as AutoSandbox and DeepScreen are active. “The infection is prevented by means of a dynamic detection,” said Sramek.
“We also automatically add detections for each new sample that passes our backend filters,” said Jiri Sejtko, Sramek’s colleague in the avast! Virus Lab.
“Against future threats like this, having a backup is always a good idea – who knows when CryptoLocker v2.0 will be released, and every antivirus solution is reactive by nature,” said Sramek. “The encryption used is virtually unbreakable, there is zero chance of recovering files after infection.”
Avast! BackUp is an online backup and recovery service that allows you to select sets of data or individual files you want to back up. Try avast! BackUp free for 30 days; after that you can choose a subscription based on your storage needs.
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Malvertising is an abbreviation of malicious advertising and means that legitimate sites spread malware from their infected advertisement systems. There were many malvertising campaigns in last few years, some of them confirmed even on big sites like The New York Times, but most of them go unnoticed because they are well hidden and served only to selected users. Earlier this year, one of our top analysts found a stealth infection on a Czech entertainment site and began to watch it. We were able to obtain source code from infected sites, and I would like to show you how easily hacking is done and what can be done to secure your server.
In this case all infected servers contained OpenX (open source solution for advertisement) which has a rich history of vulnerabilities. Look, for example, at last three versions.
- In version 2.8.9 and previous versions there was a SQL injection
- Version 2.8.10 contained a hidden backdoor that allowed remote PHP execution
- The latest version 2.8.11 offers more security, but there are known vulnerabilities
In summer 2013, OpenX was re-branded as Revive Adserver and several security flaws were patched. I strongly recommend you update to the latest version (currently 3.0.0) to secure your advertisement solution from being misused by hackers.
How do they get in?
An analysis of infected web pages revealed that the attacker used SQL injection to obtain administrator log ins and passwords from the database. Then he used credentials to log in and exploited another flaw to upload a backdoor with executable extension. Actually there were more backdoors and PHP scripts hidden in various places suggesting that this server was attacked multiple times.
This picture shows all scripts and their dates of creation found on the infected page. The first three files are backdoors and tools for server control. The last two files are different; they serve as an interface to the database.
Files “inj” and “minify” seem to be two versions of the same script, which connects to the database and either removes injected scripts or add new ones. The result of this modification is an iframe appended to advertisement banners. The picture below shows a SQL query used to insert malicious java-script.
The described infection is really hard to trace, because it’s not present on the server all the time, but only in predefined times and shows only to users coming from specific zone. Read more…
This question, from a small-site owner with tens or hundreds of visitors per day, is an unfortunate but all too familiar one.
One morning I started getting emails from my customers complaining that their antivirus reported my site as infected and won’t let them in. It must be some mistake because I don’t have an e-shop. There is just a contact form and information for customers. Is it possible that someone is attacking my business?
Why do hackers attack small webpages when there are larger targets?
Small websites have a very low frequency of updates, and the possibility that somebody would find and fix malicious code is almost non-existent, which make them attractive targets to hackers. Hackers seek unpatched pages based on open-source solutions because they can attack them quickly and easily. These pages are later used for sorting users – by those who have vulnerable applications on their computer and by those who cannot be attacked – or simply to hide their true identity. Attackers close “the door” behind them by patching the vulnerability that leads them in and simultaneously create another backdoor, only for them, so the page does not show as suspicious when tested for vulnerabilities.
In general, there are three common types of hacking events a web administrator could encounter:
This type is recognizable on the first look because the site has been changed to display a message from hackers showing off their skills and mocking the web administrator. This is usually a less harmful attack, and although your page was deleted, you don’t have any financial loss because the motivation for this attack was to show the lack of security on your pages and get credit from other hackers. People which make these attacks usually follow the rule, Don’t learn to hack, hack to learn.
For example, there are PHP shells that lets you select the method and reason of defacement and post it online. The image below shows part of a PHP-shell that sends statistics.
According to statistics from Zone-H, there were 1.5 million sites defaced during 2010, and the screenshot to the right shows the reasons for the attacks. A million and half seems like big number, but these are only documented attacks and the actual number would be much higher.
During the last few years, defacement has been used to display political or ethical opinions by attacking sites with lots of daily visitors. This is turn attracts media and gets as much attention as possible. Even antivirus companies are not spared, as you can read in a recent article about the hack against AVAST.
In today’s world where malware evolves and develops rapidly, sharing security information is the key element for success. Companies which ignore this fact sooner of later suffer from the consequences of their bad decision. Malware researchers from all over the world regularly meet at various IT security conferences, where they learn from each other how to fight with malware and how to make the IT world a safer place.
“Who wouldn’t want to have more likes on their Facebook page?” This is the motivation of a very trivial code to get more likes, but while other methods usually comprise of adding better content or advertising, this one is a bit easier, and much dirtier. Why not show the like button directly beneath your mouse cursor as you browse a website, make it invisible, and move it as you move your mouse?
The only thing the victim has to do is click; if they are logged in to Facebook, they will automatically like the Facebook page. And of course, it is not only about the number of likes, but each like means the victim will get all the information about this page on their news feed (until they unlike the page), and all friends will also see that you like it – so why not check it out themselves?
This method is possible due to Like Button, a social plugin for Facebook, made by Facebook developers. It is used properly on many legitimate sites, but when combined with CSS hiding and JS moving, the victim has no other chance. If you want to know how to minimize the impact of such tactics, or if you are more into technical details, read on.
PHP.net users that would like to access php.net were unpleasantly surprised today. Google flagged the website as suspicious and users of the Google Chrome and Mozilla Firefox browsers saw a security warning when they tried to visit the website.
According to the Google diagnostic page, suspicious content was found on php.net on October 23rd, 2013. Three domains were mentioned; cobbcountybankruptcylawyer.com, stephaniemari.com, and northgadui.com (owned by the same GoDaddy account) which were said to distribute malware to visitors of the site. Read more…
A few weeks ago, I discovered and Julia warned you about a fake AVAST application which was infecting smartphones. It was hidden behind adult apps and was pretty nasty. Here is some detailed information about it.
First of all, if you look for adult applications (also known as pleasure applications J ), you can find tons of them. Some apps, especially those offered on unofficial markets, are infected by malware; in the case of the fake AVAST app, it was ransomware. The same scenario commonly plays out – after installation when you play the application for the first time, you get infected and blocked from using your phone. The app asks for money to unblock you phone. That’s typical ransomware behavior.
The clues are easy to spot
You are looking for a adult application and run across something called AVASTME.NOW. What the hell is going on here, you might think? The fact that an adult app is named after the world’s most trusted antivirus might be your first clue that something is wrong. But you install the app, even though it’s a pretty weird name for an app designed for adults. Luckily, after the installation you get an icon on your device called Porn Hub, so you start to feel satisfied you actually got what you were looking for. So let’s play it!
But this satisfied feeling does not stay forever. After the first few clicks, the application announces your phone must be checked for viruses. That‘s the second big clue that something might be wrong. Normal applications do not check your phone for viruses. But you don‘t have any choice, so you continue. That’s when you see a fake avast! Mobile Security interface which is almost identical to the original.
Here comes a third clue for sharp-eyed users: All the detections you see on the screen use a different format than AVAST. But it‘s already too late to stop the app. In the next step, you are asked to pay $100 to clean up your phone. And your device is locked.
Sloppy, but effective
This ransomware is easily packed, and it’s apparent that the creators tried to do it as quickly as possible. Strings of detections don‘t have any kind of background, and it appears that it used randomly generated names from multiple antiviruses, as you see in the screenshot below. They were even too lazy to clean up unnecessary icons from the package, so you can find a picture of a cat in it (maybe it‘s the unhappy cat of some of the creators? ) Even though the app was sloppily done, the cybercrooks were successful and earned/stole large sums of money.
This is just one example of the many applications out there waiting to steal money from you. It doesn’t have to be for adults only; basically any application might be misused against you. That‘s why everyone should be a careful and download applications only from trusted sources. Because malware like this is increasing, it especially prudent to use some kind of antivirus protection. We suggest (the authentic) avast! Mobile Security, available from the Google Play store. It’s free! You never know when you will get something like this, so install it today on your Android device.
It has been more than a year, since we last time reported about Reveton lock screen family. The group behind this ransomware is still very active and supplies new versions of their ransomware regularly.