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Trojan.Milicenso

Risk Level 1: Very Low

Discovered:
July 14, 2010
Updated:
October 29, 2012 10:09:13 AM
Also Known As:
Troj/Agent-YOJ [Sophos]
Type:
Trojan
Systems Affected:
Windows 2000, Windows 7, Windows Server 2003, Windows Server 2008, Windows Vista, Windows XP
CVE References:
CVE-2010-2729
This threat may attempt to spread by exploiting the following vulnerability:
Microsoft Windows Print Spooler Service Remote Code Execution Vulnerability (CVE-2010-2729)

If a system has been patched for the above vulnerability, the Trojan may create the following files, which may then be printed:
  • %Windir%\system32\spool\PRINTERS\[FILE NAME ONE].SPL
  • %Windir%\system32\spool\PRINTERS\[FILE NAME TWO].SPL
  • %Windir%\system32\spool\PRINTERS\[FILE NAME ONE].SHD
  • %Windir%\system32\spool\PRINTERS\[FILE NAME TWO].SHD

When the Trojan is executed, it checks for the presence of a virtual environment (e.g. VMWare). It also performs checks to determine if it is running within a malware analysis environment. If these checks fail, the Trojan drops a copy of Adware.Eorezo and then drops the following file:
%Temp%\[RANDOM CHARACTERS].bat

The above file is a script that deletes the originally executed file and removes any presence of the threat from the compromised computer.

If the checks pass, the Trojan drops the following file:
%System%\[RANDOM CHARACTERS].dll (Packed.Generic.371)

It then creates the following system task so that it executes whenever Windows starts:
%Windir%\Tasks\[RANDOM CHARACTERS].job

The Trojan then creates the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"[ONE SINGLE DIGIT]" = "[BINARY DATA]"
HKEY_LOCAL_MACHINE\SOFTWARE\[SEVEN RANDOM CHARACTERS REGISTRY SUBKEY]\"[RANDOM CHARACTERS REGISTRY ENTRY]" = "[ENCRYPTED DATA]"

Next, the Trojan creates the following registry entry to bypass the Windows firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List\"1900:TCP" = "1900:TCP:LocalSubNet:Enabled:UDP 1900"

The Trojan creates the following registry entries to alter Internet Explorer settings:
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"2" = "[BINARY DATA]"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"4" = "[BINARY DATA]"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"5" = "[BINARY DATA]"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"7" = "[BINARY DATA]"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"8" = "[BINARY DATA]"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"9" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"2" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"4" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"5" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"7" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"8" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\"9" = "[BINARY DATA]"

It then creates the following registry entries:
  • HKEY_CURRENT_USER\Software\[RANDOM CHARACTERS REGISTRY SUBKEY]\"[RANDOM CHARACTERS REGISTRY ENTRY]" = "[BINARY DATA]"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"1" = "[RANDOM CHARACTERS]"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"10" = "[RANDOM CHARACTERS]"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"3" = "[RANDOM CHARACTERS]"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"4" = "[RANDOM CHARACTERS]"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"5" = "1"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"7" = "1"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"8" = "1"
  • HKEY_CURRENT_USER\System\CurrentControlSet\"9" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ESENT\Process\FreeCodec_I\DEBUG\"Trace Level" = ""
  • HKEY_LOCAL_MACHINE\SOFTWARE\[RANDOM CHARACTERS REGISTRY SUBKEY]\"[RANDOM CHARACTERS REGISTRY ENTRY]" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"1" = "[RANDOM CHARACTERS]"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"10" = "[RANDOM CHARACTERS]"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"3" = "[RANDOM CHARACTERS]"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"4" = "[RANDOM CHARACTERS]"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"5" = "1"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"7" = "1"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"8" = "1"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\"9" = "1"
  • HKEY_USERS\.DEFAULT\Software\[RANDOM CHARACTERS REGISTRY SUBKEY]\"[RANDOM CHARACTERS REGISTRY ENTRY]" = "[BINARY DATA]"
  • HKEY_USERS\.DEFAULT\System\CurrentControlSet\"5" = "1"

The Trojan then decrypts two component files that contain URLs and keywords. It may then connect to some of the following domains to download adware programs on to the compromised computer:

The Trojan then accesses the following URLs:
  • [http://]172.181.42.29
  • [http://]ads.alpha00001.com
  • [http://]allnighters.in
  • [http://]amandalikeguarana.ru
  • [http://]chelseaof.ru
  • [http://]incotel.kz
  • [http://]incotel.kz/cgi-bin/shoppi[REMOVED]
  • [http://]london-of10.ru
  • [http://]robinbobin20.ru
  • [http://]storage1.static.itmages.ru
  • [http://]storage5.static.itmages.ru
  • [http://]wildcounter.net
  • [http://]wildcounter.net/html/license_[RANDOM [REMOVED]

Recommendations

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: Kaoru Hayashi and Branko Spasojevic
Summary| Technical Details| Removal

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