Remove the Adkoob Malware — a Facebook Stealing Hybrid Trojan/Hjacker Virus

Remove the AdKoob Malware — a Facebook Stealing Hybrid Trojan/Hjacker Virus

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The AdKoob malware is a hybrid Trojan and hijacker virus which has recently been discovered in a global attack campaign. It is distributed using various methods and features many modules that are executed following the infection. Our article gives a detailed overview of the infection process and a full removal guide on deleting the AdKoob malware and restoring the victim computers.

Threat Summary

TypeBrowser Hijacker, Trojan
Short DescriptionThe AdKoop malware features an extensive list of modules that are configured to steal user data and modifying sensitive system settings.
SymptomsThe victims may not experience any apparent symptoms of infection.
Distribution MethodFreeware Installations, Bundled Packages, Scripts and others.
Detection Tool See If Your System Has Been Affected by AdKoob


Malware Removal Tool

User ExperienceJoin Our Forum to Discuss AdKoob.

AdKoob Malware – Distribution Methods

The research into the AdKoob malware began when security experts detected suspicious behavior of a legitimate Windows binary file (svchost.exe). During the investigation the experts were able to identify a new threat resulting in AdKoob’s discovery. This clearly shows that there is an advanced delivery method used to spread the initial payloads leading to the infection. There are several possible scenarios how this can be achieved.

The first method is the coordination of SPAM email campaigns that utilize various phishing techniques. A typical message includes design elements taken from famous companies or Internet services attempting to coerce the victim uses into interacting with the malicous element. The AdKoob malware payload file can be either attached or linked in the body contents.

The other strategy is to create fake download sites that are used to host the malicious instances. Usually virus files that contain the AdKoob malware come under the form of infected payloads. Two main types are the following:

  • Infected Documents —The hackers can bundle the AdKoob payload into scripts that are embedded in documents: rich text documents, spreadsheets or presentations. When they are opened by the victims a notification prompt will appear asking the users to enable the macros. If this is done the infection sequence will be started.
  • Malware Software Installers — Using a similar method the criminals can download the legitimate setup files of popular software. This is software that is frequently used by the users: productivity apps, creativity suites or system utilities. The resulting installers are then uploaded to the fake download portals or linked in the email messages.

Likewise the criminals behind the AdKoob malware can embed various malicious scripts to redirect the users to the malicious files. There are many examples: scripts, redirects, in-line hyperlinks, banner ads or pop-ups.

Advanced campaigns can take advantage of browser hijackers — they represent malicious extensions made for the most popular web browsers. The hackers utilize fake developer credentials and user reviews along with an elaborate description of the item. This isused to coerce the victims into installing it. The most likely places to find such pieces of malware are the fake download portals or the official plugin repositories. Once installed these malicious extensions follow a common behavior pattern — first they will modify the default settings (home page, search engine or the new tabs page). This is followed by the virus infection and any other malware actions configured by the hackers.

AdKoob Malware – Detailed Description

Warning! The AdKoob malware is considered a Trojan/Hijacker hybrid threat.

The security analysis of the AdKoob malware shows that attack sequence follows a multi-stage behavior pattern. The payload is made up of an open-source UPX packer or a custom injector. The next step is to inject the malware code into the service host process.

Following the successful infection the AdKoob malware will present a fake error message in an application frame “Unable To Locate Component” with the following contents:

The configuration file is missing. Re-installing Easy Backup may fix this problem.

This shows that the captured sample may be distributed via a malicious software installer for a backup software. The analysis shows that the main malicious engine performs a security check looking for a specific string in the %appdata% service folder. This is related to the configuration of the virus to run only once.

The engine ha been found to execute a stealth protection module which protects the AdKoob malware from discovery. It will scan the system for the presence of anti-virus programs, sandbox environments, virtual machines and other software that can interfere with its correct execution. The associated real-time engines may be disabled and the programs completely removed.

Once this is complete the virus engine will proceed with the first stage of the actual malicious process. It will start to analyze the Windows Registry and hijack sensitive data about the host and the users. There are two main groups of data that are usually categorized:

  • Personal Data — It is made up of information that can reveal details about the user and expose their identity. This includes data sets such as their real name, interests, phone number, location and stored account credentials.
  • Campaign Metrics — This data set consists of information that is useful for optimizing the attacks. It is usually made up of reports that give details on the installed hardware components and certain operating system values on the compromised machines.

Depending on the installed and targeted web browsers AdKoob uses different infiltration techniques. For older versions of Mozilla Firefox and Google Chrome the malicious engine attempts a SQL query against the built-in databases. Newer versions of Mozilla Firefox utilizes another method — they store the account credentials within a JSON file. The AdKoob malware contains code that can specifically query and extract this information. Internet Explorer browsers store some values from the Windows Registry. It can also use specific credentials to exfiltrate the sensitive data.

This browser hijacker behavior is merely the first part of the malware’s behavior pattern. Following this the virus will continue with a Trojan module. It determines the public IP address of the infected host by making a request to a service Internet. A secured connection is made to a hacker-controlled command and control servers. This reports the infection, the decrypted stream contains the following values:

  • Unique Machine Identifier
  • Operating System Version
  • Public IP
  • Local timezone of the victim’s machine
  • Browser Identifier String
  • Browser User Agent
  • Base64 Encoded Credentials
  • Bot Identifier

AdKoob Malware – Trojan Operations

Once the Trojan engine has started it looks for active Facebook sessions. It establishes a connection originating from the victim’s profiles. There are two main methods that are used to run this operation:

  1. Stored Authentication Cookies — This is achieved when the AdKoob malware has been able to find the cookies via a data harvesting infiltration.
  2. Browser Credentials Theft — The AdKoob malware attempts to login to the services if it has already acquired the credentials for Facebook.

It appears that there are several specific types of information that are looked up by the malware:

  • Facebook Locale — This is the parameter which is used to define the user’s set language and region.
  • Facebook User ID — A string which is used to connect the Facebook users to the social service.
  • Facebook Profile Username — The usernames chosen by the users.
  • User Information — This includes all data sets that are posted by the users and are displayed om their profiles: their real name, location, birthday, contact information and etc.
  • Facebook Pages — This includes a list of the Facebook pages have been created by the user.

The AdKoob malware then continues further by interacting with an interface that makes a series of requests related to paid advertisement campaigns. When used by companies the AdKoob can be used to deliver personalized, targeted or mass ad campaigns on the infected hosts. The administrative panel allows the operators to coordinate targeted ads. The menu options present various options and specific parameters that can be toggled.

The underlying engine that is responsible for these actions uses a two-direction request and reply method. The infected hosts reports information about the accessed ad pages, while the server instance gives specific instructions on the chosen pages. This leads to the construction of a specific account ID that as a result creates a query to the Facebook Graph API — an API interface that is used to query data from a Facebook account. The query results in data about the ad campaigns — name, spent money and budget limit.

This fact gives security researchers the notion that AdKoop operators are targeting business users. This comes from the premise that regular home users are not likely to use Facebook advertisement campaigns. The harvested information is exfiltrated and sent to the C&C servers.

Following the successful execution of all components the AdKoob malware will remove all traces of itself and leave a specific marker file that ensures that the virus is not run twice.


Martin Beltov

Martin graduated with a degree in Publishing from Sofia University. As a cyber security enthusiast he enjoys writing about the latest threats and mechanisms of intrusion.

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