Follow:

 

Win32/Rorpian


Win32/Rorpian are a family of worms capable of spreading through network shares and by exploiting vulnerabilities such as the Domain Name System (DNS) Server Service vulnerability. The worm usually downloads additional malware on the affected computer.


What to do now

To detect and remove this threat and other malicious software that may be installed on your computer, run a full-system scan with an appropriate, up-to-date, security solution. The following Microsoft products detect and remove this threat:

For more information on antivirus software, see http://www.microsoft.com/windows/antivirus-partners/.

Threat behavior

Win32/Rorpian are a family of worms capable of spreading through network shares and by exploiting vulnerabilities such as the Domain Name System (DNS) Server Service vulnerability. The worm usually downloads additional malware on the affected computer.

Installation

Upon execution, Worm:Win32/Rorpian copies itself to the %TEMP% folder using a file name in the format “srv<random number>.tmp”. For example:

  • %TEMP%\srv950.tmp
  • %TEMP%\srv864.tmp

It also creates a text file in the %TEMP% folder with the same name as its dropped copy, but with a “.ini” extension. For example:

  • %TEMP%\srv950.ini
  • %TEMP%\srv864.ini

The worm then creates the following registry entries to ensure its copy executes at each Windows start:

In subkey: HKLM\system\currentcontrolset\services\srv\parameters
Sets value: "servicedll"
With data: "\\?\globalroot\device\harddiskvolume1\%TEMP%\srv<random number>.tmp"

In subkey: HKLM\software\microsoft\windows nt\currentversion\svchost
Sets value: "netsvcs"
With data: "srv<random number>"

In subkey: HKLM\system\currentcontrolset\services\srv<random number>
Sets value: "imagepath"
With data: "%systemroot%\system32\svchost.exe -k netsvcs"

In subkey: HKLM\system\currentcontrolset\control\safeboot\minimal\srv<random number>
Sets value: “(default)”
With data: “service

Spreads via...

Network shares

Worm:Win32/Rorpian spreads by enumerating all network shares, copying itself to the share, along with a number of other files. It also creates an autorun.inf file that launches the worm executable when the share is accessed, as well as a shortcut (.LNK) file which exploits the vulnerability described in Microsoft Security Bulletin MS10-046.

The files it creates in discovered shares are listed below:

Via exploits

Some variants of Worm:Win32/Rorpian have the capability of spreading by exploiting a vulnerability in the Domain Name System (DNS) Server Service. The worm does a network scan in order to search for exploitable computers, copying itself to the computer if it is vulnerable. More information about this vulnerability can be found here: Microsoft Security Bulletin MS07-029

Payload

Downloads and executes arbitrary files

Worm:Win32/Rorpian is also capable of downloading and executing additional malware on the compromised computer. It contacts a particular I.P. address and downloads files to the %Windows%\temp folder using file names such as “e.tmp”, “f.tmp”, and “10.tmp”. It may contact a number of URLs that have the format shown below:

  • hxxp://<domain>//srv
  • hxxp://<domain>/service/listerner.php?affid=<number>
  • hxxp://<domain>//dll
  • hxxp://<domain>/service/scripts/files/aff_<number>.dll
  • hxxp://<domain>/soft/installer_m_<number>.exe

At the time of writing, variants of this worm have been observed downloading Win32/Alureon onto the affected computer. Later variants have also been observed downloading and installing Rogue:Win32/FakeRean.

Analysis by Amir Fouda


Symptoms

System changes

The following system changes may indicate the presence of this malware:

  • The presence of the following files:

    %TEMP%\srv950.tmp
    %TEMP%\srv864.tmp
    %TEMP%\srv950.ini
    %TEMP%\srv864.ini
    setup.fon
    setup.lnk
    myporno.avi.lnk
    pornmovs.lnk
    autorun.inf
  • The presence of the following registry modifications:

    In subkey: HKLM\system\currentcontrolset\services\srv\parameters
    Sets value: "servicedll"
    With data: "\\?\globalroot\device\harddiskvolume1\%TEMP%\srv.tmp"

    In subkey: HKLM\software\microsoft\windows nt\currentversion\svchost
    Sets value: "netsvcs"
    With data: "srv"

    In subkey: HKLM\system\currentcontrolset\services\srv
    Sets value: "imagepath"
    With data: "%systemroot%\system32\svchost.exe -k netsvcs"

    In subkey: HKLM\system\currentcontrolset\control\safeboot\minimal\srv
    Sets value: “(default)”
    With data: “service

Prevention

Take the following steps to help prevent infection on your computer:
  • Enable a firewall on your computer.
  • Get the latest computer updates for all your installed software.
  • Use up-to-date antivirus software.
  • Limit user privileges on the computer.
  • Use caution when opening attachments and accepting file transfers.
  • Use caution when clicking on links to webpages.
  • Avoid downloading pirated software.
  • Protect yourself against social engineering attacks.
  • Use strong passwords.
Enable a firewall on your computer

Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.

Get the latest computer updates

Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor websites.

You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.

Use up-to-date antivirus software

Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software, such as Microsoft Security Essentials, that is updated with the latest signature files. For more information, see http://www.microsoft.com/windows/antivirus-partners/.

Limit user privileges on the computer

Starting with Windows Vista and Windows 7, Microsoft introduced User Account Control (UAC), which, when enabled, allowed users to run with least user privileges. This scenario limits the possibility of attacks by malware and other threats that require administrative privileges to run.

You can configure UAC in your computer to meet your preferences:

Use caution when opening attachments and accepting file transfers

Exercise caution with email and attachments received from unknown sources, or received unexpectedly from known sources. Use extreme caution when accepting file transfers from known or unknown sources.

Use caution when clicking on links to webpages

Exercise caution with links to webpages that you receive from unknown sources, especially if the links are to a webpage that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your computer simply by visiting a webpage with harmful content.

Avoid downloading pirated software

Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information, see 'The risks of obtaining and using pirated software'.

Protect yourself from social engineering attacks

While attackers may attempt to exploit vulnerabilities in hardware or software to compromise a computer, they also attempt to exploit vulnerabilities in human behavior to do the same. When an attacker attempts to take advantage of human behavior to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted computer. For more information, see 'What is social engineering?'.

Use strong passwords

Attackers may try to gain access to your Windows account by guessing your password. It is therefore important that you use a strong password – one that cannot be easily guessed by an attacker. A strong password is one that has at least eight characters, and combines letters, numbers, and symbols. For more information, see http://www.microsoft.com/protect/yourself/password/create.mspx.


Alert level: Severe
This entry was first published on: May 19, 2011
This entry was updated on: May 19, 2011

This threat is also detected as:
No known aliases