Alert level

TrojanDownloader:Win32/Renos.HL


Encyclopedia entry
Updated: Apr 09, 2009  |  Published: Apr 01, 2009

Aliases
  • Pro Antispyware 2009 (other)
  • MS AntiSpyware 2009 (other)
  • W32/DLoader.NYHM (Norman)
  • Mal/FakeAV-AH (Sophos)
  • Win32/Adware.MSAntispyware2009 (ESET)
  • Downloader.MisleadApp (Symantec)
  • Trojan.Fakeavalert (Symantec)
  • Trojan-Downloader.Win32.FraudLoad.dzd (Kaspersky)
  • Generic Downloader.x (McAfee)

Alert Level (?)
High

Antimalware protection details
Microsoft recommends that you download the latest definitions to get protected.
Detection last updated:
Definition: 1.67.848.0
Released: Oct 15, 2009 		Detection initially created:
Definition: 1.51.1176.0
Released: Feb 26, 2009

Summary

Trojan:Win32/Renos.HL is an installer that connects to specified websites to download and install a fake antivirus scanner. This scanner is detected as Trojan:Win32/WinSpywareProtect.
 
Note  6th April 2009: We have received reports that TrojanDownloader:Win32/Renos.HL has been distributed attached to an email that masquerades as a message from Microsoft. The message reads as follows:
 
From: Microsoft Computer Safety Department
Subject (or similar): Microsoft Alert (Case#: wlTR6Zm)
 
Dear Windows User,
Starting April 1st, 2009 the "Comficker" virus began infecting Microsoft customers very quickly.
Microsoft was alerted by your Internet provider that your computer is showing signs of being infected.
To prevent further infection we recommend removing the infection using an antivirus program
We are giving all effected Microsoft customers a free antispyware scan in order to remove any infections from their system.
Please visit the Microsoft Windows System Security Scanner website by clicking here to start scanning your computer.
The process takes under a minute and will prevent your information from being stolen.
We appreciate your cooperation in this matter.
 
Regards
Microsoft Windows Representative #10(Willa)
Windows Net Security Division
Email Ref ID: g9BK0f
 
This email was not sent by Microsoft and is an attempt to use the current interest and concern over Win32/Conficker in order to persuade users to download and install arbitrary files of the attacker's choice - in this case, Trojan:Win32/Renos.HL and in turn Trojan:Win32/WinSpywareProtect.
Additional information on how to help verify the legitimacy of a Microsoft e-mail can be found here:

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Symptoms

System Changes
The following system changes may indicate the presence of this malware:
  • The presence of the following registry modifications (for example):
    • Under key: HKCU\Software\<software company name>\upd
    Adds value: Started
    With data: <8 bytes> (for example C9 95 98 1E 73 62 26 41)
    Adds value: Ready
    With data: 0
     
    Under key: HKCU\Software\<software company name>\<fake scanner name>
    Adds value: lid43211q75rerqq
    With data: “-1”Adds value: pid
    With data: <random digits> (for example 11020)
    Adds value: psid
    With data: “1” or “123” or “0”
     
    Examples of <software company name> include:
    Solt Lake Software
    CrucialSoft Ltd
     
    Note: <fake scanner name> is a product name, such as one of the examples listed above (i.e. Pro Antispyware 2009 or MS AntiSpyware 2009).
  • The display of the following message:

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Technical Information (Analysis)

Trojan:Win32/Renos.HL is an installer that connects to specified websites to download and install a fake antivirus scanner. This scanner is detected as Trojan:Win32/WinSpywareProtect.
Installation
Trojan:Win32/Renos.HL runs from its original location. It creates the following registry entry to ensure that it will run on system startup:
Under key: HKCU\Software\Microsoft\Windows\CurrentVersion\Run
Adds value: Installer
With data: <full pathname of malware>
Payload
Downloads and Installs Rogue Security Software
When executed, Trojan:Win32/Renos.HL may display a dialog, similar to the one shown below, prompting the user to choose from one of a number of installation languages, and to click Continue.
Once the user has performed the actions suggested by the dialog, it then connects to a specified website to download and install the fake scanner. Examples of websites used include the following:
  • dl.as-storage.net
  • dl.ms-antivir-scan.com
  • dl.ms-scanner-antivir.com
 
Some variants of the malware silently attempt to download the fake scanner without displaying a dialog.
 
The malware may also contact further websites in order to update download statistics. Examples of these include:
  • int.sysproreport1.com
  • int.sysproreport2.com
  • int.proreportms1.com
  • int.proreportms2.com
  • int.msproreport1.com
 
The fake scanner regularly changes its branding and graphical layout. The following names have been observed being used:
  • Pro Antispyware 2009
  • MS AntiSpyware 2009
Additional Information
During installation, TrojanDownloader:Win32/Renos.HL may create registry entries such as the following:
 
Under key: HKCU\Software\<software company name>\upd
Adds value: Started
With data: <8 bytes> (for example C9 95 98 1E 73 62 26 41)
Adds value: Ready
With data: 0
 
Under key: HKCU\Software\<software company name>\<fake scanner name>
Adds value: lid
With data: “-1”
Adds value: pid
With data: <random digits> (for example 11020)
Adds value: psid
With data: “1” or “123” or “0”
 
Examples of <software company name> include:
"Solt Lake Software"
"CrucialSoft Ltd"
 
Note: <fake scanner name> is a product name, such as one of the examples listed above (i.e. Pro Antispyware 2009 or MS AntiSpyware 2009).
 
So an example registry entry might be
HKCU\Software\Solt Lake Software\Pro Antispyware 2009\lid
or
HKCU\Software\CrucialSoft Ltd\MS AntiSpyware 2009\lid.
 
Analysis by David Wood

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Prevention

Take the following steps to help prevent infection on your system:
  • Enable a firewall on your computer.
  • Get the latest computer updates for all your installed software.
  • Use up-to-date antivirus software.
  • Use caution when opening attachments and accepting file transfers.
  • Use caution when clicking on links to web pages.
  • 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.
To turn on the Windows Firewall in Windows Vista
  1. Click Start, and click Control Panel.
  2. Click Security.
  3. Click Turn Windows Firewall on or off.
  4. Select On.
  5. Click OK.
To turn on the Internet Connection Firewall in Windows XP
  1. Click Start, and click Control Panel.
  2. Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
  3. Click Change Windows Firewall Settings.
  4. Select On.
  5. Click OK.
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.
To turn on Automatic Updates in Windows Vista
  1. Click Start, and click Control Panel. 
  2. Click System and Maintainance.
  3. Click Windows Updates.
  4. Select a setting. Microsoft recommends selecting Install updates automatically and choose a time that is convenient for you. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
To turn on Automatic Updates in Windows XP
  1. Click Start, and click Control Panel. 
  2. Click System.
  3. Click Automatic Updates.
  4. Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
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 that is updated with the latest signature files. Antivirus software is available from several sources. For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.
Use caution when opening attachments and accepting file transfers
Exercise caution with e-mail 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 Web pages
Exercise caution with links to web pages that you receive from unknown sources, especially if the links are to a Web page that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your system simply by visiting a Web page 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 in order to compromise a system, they also attempt to exploit vulnerabilities in human behavior in order to do the same. When an attacker attempts to take advantage of human behavior in order 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 system. 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 8 characters, and combines letters, numbers, and symbols. For more information, see http://www.microsoft.com/protect/yourself/password/create.mspx.
Recognize and avoid fraudulent e-mail to Microsoft customers
This malware may be distributed masquerading as a message from Microsoft. Additional information on how to help verify the legitimacy of a Microsoft e-mail can be found here:

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Recovery

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as the Microsoft online scanner (http://safety.live.com). For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.

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