Internet predators

Anyone using the Internet is at risk, regardless of age and regardless of what they like to do online. Cybercriminals can deploy an impressive arsenal, targeting everyone from schoolchildren to pensioners and following them whether they are logged on to social networks, checking the latest headlines or watching their favorite videos. Internet scammers want access to our money, our personal data and the resources of our computer systems. In short, they want anything that they can profit from.

There are a huge range of different attacks facing us on the net: users can get caught by ransomware like Gimeno or Foreign, become part of the Andromeda botnet, see ZeuS/Zbot drain the cash from their bank accounts, or have their passwords compromised by Fareit spyware. Usually web attacks try to download and install an infected executable file on the target computer, but there are some exceptions, for instance XSS or CSRF, which execute embedded HTML code.

Attack mechanism

For an attack to succeed, first of all users need to connect to a malicious site that downloads an executable file onto their computers. To tempt users to the resource, scammers might send them a link by email, SMS or via a social network. They might also try to promote their site via search engines. One further technique is to hack a popular legitimate resource and turn it into an instrument to attack its visitors.

Downloading and installing malware can be done in one of two ways. The first, a hidden drive-by download, relies on using a vulnerability in the user’s software. The user of the infected site is often completely unaware that the computer is installing the malware, as usually there are no indications that this is happening.

The second method uses social engineering, where users are tricked into downloading and installing malware themselves, believing it is an updated flash player or some similar popular software.

Diagram of Internet attacks showing how executable malware files can be downloaded

Malicious links and banners

The simplest way to lure victims to malicious sites is simply to display an attractive banner with a link. As a rule sites with illegal content, pornography, unlicensed software, films etc. are used as a host. Such sites can work “honestly” for a long time to build up an audience before they start hosting banners with links to malicious resources.

One popular infection method is malvertising, or the redirecting the user to a malicious site with the help of hidden banners. Dubious banner networks attract site administrators with high payments for ‘click-throughs’ on their ads and frequently earn money “on-the-side” by spreading malware.

When users enter the site displaying these banners, a so-called “pop-under” opens in the victim’s browser. This is similar to a pop-up window, but it appears either under the main window of the site, or on an otherwise inactive neighboring tab. The contents of these “pop-unders” often depend on the location of the visitor to the site – the inhabitants of different countries are redirected to different resources. The visitors of one country might simply be shown an advert for example

Site sends American visitors to the resource watchmygf[]net

Site sends Russian visitors to the resource runetki[]tv\

…whereas visitors from other countries will be attacked by exploit packs.

An inhabitant of Japan is attacked by an exploit and infected with the Zbot spyware Trojan

On occasion these malicious banners can even penetrate into honest banner networks, despite careful scrutiny by administrators. Cases like this have affected the Yahoo Advertising banner network and even YouTube.

Spam

Spam is one of the most popular means of attracting victims to malicious resources. It includes messages sent by email, SMS and instant communications systems, via social networks, private messages on forums and comments in blogs.

A dangerous message might contain a malicious file or a link to an infected site. To encourage the user to click on a link or a file social engineering is used, for example:

• the name of a real organization or person is used as the sender’s name,
• the letter pretends to be part of a legitimate mailshot or even a personal communication,
• the file is presented as a useful program or document.

During targeted attacks, when cybercriminals specifically attack a certain organization, the malicious letter might mimic a letter from a regular correspondent: the return address, content and signature could be the same as a genuine letter, for example from a partner of the company. By opening the attached document with a name like “invoice.docx” users put their computers at risk of infection.

Black Search Engine Optimization

SEO or Search Engine Optimization is a collection of techniques to raise the position of a site in the results given by search engines. Modern users often go to search engines to find necessary information or services, so the easier it is to find a given site the more visitors it will get.

In addition to legitimate methods of optimization, those that are permissible in the eyes of the search engines, there are forbidden techniques that fool search engines. A site might “promote itself” with the help of a botnet – thousands of bots make certain search requests and select the malicious site, raising its rating. The site itself may adopt a different appearance depending on who has entered it: if it is a search robot it will be shown a page relevant to the request, if it is a normal user it will be redirected to a malicious site.

Also links to the site are distributed in forums and other sites known to search engines using special utilities, which raise the rating of the site and, consequently, its position in search results.

As a rule, sites that use black search optimization are actively blocked by search engine administrators. For this reason they are created by the hundred using automatic instruments.

Infected legitimate sites

Sometimes cybercriminals infect popular legitimate sites in order to spread their programs. These might be high-traffic news resources, internet shops or portals and news aggregators.

There are two common ways to infect sites. If a software vulnerability was detected on the target site, malicious code can be inserted (for instance an SQL injection). In other cases the malefactors obtain authentication data from the site administrator’s computer using one of the many Trojan spyware programs or using phishing and social engineering and seize control of the site. Once under the control of the criminals, the site can be infected in one way or another. The simplest approach is to use a hidden iframe tag with a link to the malicious resource added to the HTML code of the page.

Kaspersky Lab registers thousands of legitimate sites every day that download malicious code to their visitors with them being aware of it. Among the most prominent cases were the Lurk Trojan found on the site of the RIA Novosti news agency and gazeta.ru and the infection of PHP.Net

Visitors to an infected site are attacked with the use of hidden drive-by-downloads. The infection goes unnoticed by the users and does not require them to download or activate anything. An exploit, or set of exploits, is automatically downloaded from the page and, if the targeted machine has vulnerable software, a malicious executable is launched.

Exploit packs

The most effective tool to infect a victim’s computer is an exploit pack, such as Blackhole. These are hot products on the black market: exploit packs are developed to order or for widespread sale and are supported and updated. The price depends on the quantity and “freshness” of the exploits included, the ease of administration, the quality of the support, the regularity of updates and the greed of the seller.

As these attacks take place through the browser, the exploits have to use a vulnerability in either the browser itself, add-ons to it or third party software loaded by the browser to handle content. If one of these exploits is used successfully, a malicious file will be launched on the victim’s machine.

Typical set of add-ons for the Internet Explorer browser that have permission to run by default. Add-ons the vulnerabilities in which are often used to attack a system are underlined in red.

An effective pack will contain exploits for useful vulnerabilities in popular browsers and their add-ons, and also for Adobe Flash Player and other popular programs. Often exploit packs have tools for fine tuning and collecting infection statistics.

Styx exploit pack control panel

Direct download by users

Quite often cybercriminals don’t need ingenious and expensive tools to insert their malicious programs onto users’ computers. Users can simply be fooled into downloading and running malware themselves.

For instance, on entering a malicious site a user sees a preview video “for adults only”. Clicking on this brings up a message to update Adobe Flash Player, and at the same time the site immediately offers him a file to download with an authentic sounding name. By installing the “update” the user infects the computer with a Trojan.

Message appearing when trying to view an “adult” video on a malicious site

Or a web-page might appear imitating the “My Computer” window, saying that a large number of viruses have been detected on the computer. And nearby a window opens offering a free “antivirus” program to cure the problems.

An apparent offer to install a free antivirus program hiding a Trojan

Infection via social networks

Inexperienced users of social networks are open to attack by so-called semi-automatic worms. The future victim receives a message apparently from a virtual acquaintance with the offer of some attractive feature that is missing from the social network (to “dislike” a post, obtain confidential data on other users, etc.). To obtain this attractive feature the user is told to open a JavaScript terminal and enter certain code there.

Instructions for the installation of a semi-automatic Facebook worm

After these actions are carried out the worm activates and begins collecting data on the user, sending links to itself to the victim’s contacts, awarding “likes” to various posts. This last option is a paid service that the owner of the worm offers to customers. And so we come to the reason why cybercriminals go to all this trouble and break the law.

Money, money, money

Naturally nobody is attacking our computers for the intellectual challenge — the aim is money. One very popular way of illegally making money from victims is the use of Trojan ransom-ware, making it impossible to use the computer until a certain sum has been paid.

Having penetrated the user’s computer the Trojan determines the country where the infected computer is and shows the victim the corresponding disable screen, containing threats and instructions on how to pay the ransom. The language of the message and the payment method suggested by the cybercriminals both depend on the user’s country.

Usually the evildoers accuse the user of looking at child pornography or some other illegal action and then threaten a criminal investigation or to make the matter public. The assumption is that the victim will take these threats seriously and won’t risk seeking help from law enforcement agencies. In some cases the Trojan ransom-ware may threaten to destroy the contents of the hard disk if the ransom is not paid quickly.

The disable screen that Trojan-Ransom.Win32.Foreign shows users in the USA

The cybercriminals offer the option of paying this “fine” by sending an SMS to a premium number or making a money transfer using one of the payment systems. In return the user should receive an unblocking key to deactivate the Trojan, but in practice this doesn’t always happen.

Maintaining a communication channel with the victim can lead law enforcement agencies to the criminals and they frequently prefer not to take the risk, leaving the victim with a practically useless computer.

Another common method of illegal moneymaking is the collection and sale of users’ confidential data. Contact details and personal data are tradable commodities that can be sold on the black market, albeit not for a great deal of money. However, it can be a profitable sideline, especially as the collection of information does not necessarily require any malware infection. Often the victims themselves supply all the necessary information — the important thing is for the site hosting the form for the entry of data to appear reliable and authentic.

A false site collecting contact details and personal information of visitors and then signing them up for paid mobile services

Banking Trojans bring their operators large profits. These programs are designed to steal money from users’ bank accounts using distance banking systems. Malware of this type steals users’ authentication data for online banking systems. Usually this is not enough as almost all banks and payment systems require authentication using several factors – entering an SMS code, inserting a USB key etc. In these cases the Trojan waits until the user makes a payment using internet banking and then changes the payment details, diverting the money to special accounts from which the criminal can cash out. There are other ways around two factor authentication: the Trojan might intercept messages with single use passwords or freeze the system at the moment the USB key is inserted, leaving the user powerless while the criminals hijack the operation and steal the money.

Finally, another profitable business is running botnets. The infected computers in a botnet can, unnoticed, be used by the evildoers for various money-making activities: mining bitcoins, sending spam, carrying out DDOS attacks, and boosting sites’ ratings through search requests.

Counteracting threats

As we have already shown, internet threats are diverse and can threaten users almost anywhere — when reading their mail, interacting on social networks, checking the news or simply surfing. There are also many ways to protect against these threats, but they can be summarized in four keys pieces of advice:

• Always pay attention to what you are doing on the Internet: which sites you visit, which files you download and what you run on your computer.
• Do not trust messages from unknown users and organizations, do not click on links and do not open attachments.
• Regularly update frequently-used software, especially software that works with your browser
• Install up-to-date defenses and keep anti-virus databases current.

It all sounds very simple, but the growing number of infections clearly demonstrates that too many users fail to take their safety seriously and neglect to follow this advice. We hope that our overview of current internet threats will help improve the situation.