Win32/Bredolab is a downloader which is able to download and execute arbitrary files from a remote host.

What to do now

To detect and remove this threat and other malicious software that may be installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following:
For more information on antivirus software, see

Threat behavior

Win32/Bredolab is a downloader which is able to download and execute arbitrary files from a remote host.
Win32/Bredolab has changed its method of installation over time. When older variants of Win32/Bredolab are executed, they copy themselves to one of the following locations, converting their EXE to a DLL:
<system folder>\digeste.dll
<system folder>\digiwet.dll
<system folder>\mcenspc.dll
<system folder>\msansspc.dll
The registry is then modified to ensure that the DLL is loaded. For example:
To subkey: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders
Sets value: "SecurityProviders"
With data: "msapsspc.dll, schannel.dll, digest.dll, msnsspc.dll, digeste.dll"
More recent variants of Win32/Bredolab copy themselves to the %startup% folder using one of the following variable filenames:
Or they may use the following location:
  • <system folder>\wbem\grpconv.exe
Downloads and executes arbitrary files
Win32/Bredolab contacts a remote host, and receives a response from the master server that contains at least one encrypted binary. Downloaded binaries are decrypted and executed.
Win32/Bredolab may use a randomly named file name for downloaded binaries on the local machine. Binaries may be saved to the following location:
  • %windir%\Temp\wpv[numbers].exe
In the wild, Win32/Bredolab has been observed to contact the following control servers:
The following list details just a small selection of the malware known to be downloaded by variants of Win32/Bredolab:
Additional Information
Some variants of Win32/Bredolab may create the following file during execution:
  • %appdata%\wiaserva.log
Several variants of Win32/Bredolab have been the focus of various spam mass-mailings. Here is a selection of an e-mail, used in the wild, to distribute Bredolab onto user's computers:
Example email #1
Subject: Postal Tracking #IARN863188FLP4G
We were not able to deliver postal package you sent on the 14th of March in time
because the recipient's address is not correct.
Please print out the invoice copy attached and collect the package at our office.
Your United Parcel Service of America
Example email #2
Subject: Shipping confirmation for order -08244007
Thank you for shopping at our internet shop!
We have successfully received your payment.
Your order has been shipped to your billing address.
You have ordered Samsung GO N310-13G.
You can find your tracking number in attached to the e-mail document.
Please print the label to get your package.
We hope you enjoy your order!

Analysis by Scott Molenkamp


System changes
The following system changes may indicate the presence of this malware:
  • The presence of the following files:
    <system folder>\digeste.dll
    <system folder>\digiwet.dll
    <system folder>\mcenspc.dll
    <system folder>\msansspc.dll
  • <system folder>\wbem\grpconv.exe
  • The presence of the following registry modifications:
    To subkey: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders
    Sets value: "SecurityProviders"
    With data: "msapsspc.dll, schannel.dll, digest.dll, msnsspc.dll, digeste.dll"


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 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.
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 Web sites.
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
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 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 computer 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 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 8 characters, and combines letters, numbers, and symbols. For more information, see

Alert level: Severe
This entry was first published on: Sep 08, 2009
This entry was updated on: Apr 17, 2011

This threat is also detected as:
No known aliases