Norton.com > Viruses & Risks > Backdoor.Salgorea

Backdoor.Salgorea

Risk Level 1: Very Low

Discovered:
March 17, 2013
Updated:
March 18, 2013 4:52:15 AM
Type:
Trojan
Infection Length:
Varies
Systems Affected:
Windows 2000, Windows 7, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows Server 2008, Windows Vista, Windows XP
This threat may arrive through spam email. The spam email attachment contains a malicious .hta file.

When the Trojan runs, it copies itself as the following files:
  • %Temp%\[RANDOM FILE NAME].exe
  • %UserProfile%\Application Data\Microsoft\Windows\AeroGlass.theme
  • %UserProfile%\Application Data\Microsoft\Windows Sidebar\sidebar.exe

It creates a partially modified copy of itself to the temporary folder and executes this copy with parameter "--help".

The Trojan also creates the following clean file and runs it:
%Temp%\KeePass.exe

It then creates the following schedule task files in order to execute the file sidebar.exe daily:
  • %Windir%\Tasks\Sidebar.job
  • %Windir%\Tasks\Sidebar_[CURRENT USER].job

Next, the Trojan creates the following registry entry so that it runs every time Windows starts:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Sidebar" = "%Temp%\[RANDOM FILE NAME].exe"

It also creates the following registry entries:
    • HKEY_CURRENT_USER\Software\Microsoft\Keyboard\"es-ec" = "[ENCODED DATA]"
    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Keyboard\"es-ec" = "[ENCODED DATA]"
    • HKEY_CURRENT_USER\Software\Microsoft\SideShow\Gadgets\"Language" = "[TIME OF INFECTION]"
    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DevDiv\UC\"SP" = "[TIME OF INFECTION]"
    • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\SideBar\OemCustomTheme\"(Default)" = "%UserProfile%\Application Data\Microsoft\Windows\AeroGlass.theme"
    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\SideBar\OemCustomTheme\"(Default)" = "%UserProfile%\Application Data\Microsoft\Windows\AeroGlass.theme"

    When the file sidebar.exe runs, it searches for one of the following files:
    • %System%\fsquirt.exe
    • %System%\sigverif.exe
    • %SystemDrive%\syswow64\colorcpl.exe
    • %System%\colorcpl.exe
    • %ProgramFiles%\Internet Explorer\ielowutil.exe
    • %ProgramFiles%\Messenger\msmsgs.exe
    • %ProgramFiles%\Internet Explorer\iexplore.exe
    • %ProgramFiles%\Internet Explorer\iexplore.exe

    If it finds one of the files mentioned above, it runs the file and injects itself into the newly created process.

    The Trojan then randomly connects to one of the following predefined URLs in order to open a back door on the compromised computer, allowing a remote attacker to perform various actions:
    • ssl.zin0.com:9999/tcp
    • zone.apize.net:8768/tcp
    • untitled.po9z.com:9999/tcp

    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: Yana Liu

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