1. Symantec/
  2. Security Response/
  3. Trojan.Obvod


Risk Level 1: Very Low

July 14, 2012
July 16, 2012 6:13:57 AM
Infection Length:
85,504 bytes
Systems Affected:
This threat may arrive on the compromised computer through drive-by downloads from Web exploit packs.

When the Trojan executes, it copies itself to the following location:
%UserProfile%\Application Data\[RANDOM CHARACTERS].exe

The Trojan creates the following .job files so that it runs every time Windows starts:

Note: Any existing scheduled tasks with the same .job file name will be overwritten.

Next, it may delete the following files:
  • %UserProfile%\Cookies\*ad*.txt
  • %UserProfile%\Application Data\Macromedia\Flash Player\*

The Trojan then lowers security settings by modifying entries under the following registry subkeys:
  • HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\New Windows
  • HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones

It may create the following mutexes so that only one instance of the Trojan is running:
  • gjigojfd3HJ
  • FJIfjoi3r4
  • HFudfjifejifb
  • jIOFjejioAD
  • JfsiJSS
  • HfhfioSjs
  • FHifsoSDks
  • FJiofjs
  • j5hfURWHIrwh

The Trojan performs click-fraud by surreptitiously contacting several ad servers pretending to have been referred from legitimate websites. It performs the following actions:
  • Finds the Cookies folder and deletes cookie files with the *ad*.txt format
  • Clears the Web browser's cache
  • Clears the Flash Player cache
  • Automatically clicks the OK button for any Internet Explorer pop-up window
  • Automatically clicks the Yes button for any Adobe Flash Player 9 pop-up windows
  • May download and decrypt files
  • May download and execute files

The Trojan may contact the following servers:
  • [http://]109.230.217/0xabad1[REMOVED]
  • [http://]*.hfuidhfd.jp
  • [http://]*.internationalforte.com

It may also contact the following DNS servers:

It may also contact the following ad servers:
  • http://ad.103092804.com
  • http://ad.adserverplus.com
  • http://ad.bharatstudent.com
  • http://ad.globe7.com
  • http://ad.harrenmedianetwork.com
  • http://ad.media-servers.net
  • http://ad.reduxmedia.com
  • http://ad.scanmedios.com
  • http://ad.xertive.com
  • http://ad.z5x.net
  • http://ads.audienceamplify.com
  • http://ads.sonobi.com
  • http://ads.yieldads.com
  • http://adserving.cpxadroit.com
  • http://ib.adnxs.com


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Nino Fred Gutierrez
Summary| Technical Details| Removal

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