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Win32/Daurso


Win32/Daurso is a family of trojans that attempts to steal sensitive information, including passwords and  FTP authentication details from affected computers. This family targets particular FTP applications and also attempts to steal data from Protected Storage.


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 http://www.microsoft.com/windows/antivirus-partners/.

Threat behavior

Win32/Daurso is a family of trojans that attempts to steal sensitive information, including passwords and  FTP authentication details from affected computers. This family targets particular FTP applications and also attempts to steal data from Protected Storage.
Installation
In the wild, we have observed Win32/Daurso being installed onto affected computers by variants of Win32/Bredolab. It may be installed to the following location:
  • <system folder>\wbem\proquota.exe
 
Note - <system folder> refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the System folder for Windows 2000 and NT is C:\Winnt\System32; and for XP and Vista is C:\Windows\System32.
 
When run, Win32/Daurso creates the following mutex to ensure that multiple instances of Daurso do not run simultaneously:
  • mutex_io
Payload
Steals sensitive information
Win32/Daurso queries the registry and traverses folders and files found in the system to look for sensitive information that it later sends to a remote address. It also targets Protected Storage in this manner.
 
Win32/Daurso has been observed to specifically target the following applications:
 
CoffeCup Free FTP
COREFTP
Far
Total Commander
FTP Control 4
CuteFTP
FileZilla
FlashFXP
SmartFTP
FFFTP
FTP Navigator
 
In the wild, Win32/Daurso has been observed sending captured information to the following remote hosts:
  • 78.109.30.224
  • hostvegass.ru
  • fdiggit.cn
  • abbcp.cn
 
Analysis by Scott Molenkamp

Symptoms

System changes
The following system changes may indicate the presence of this malware:
  • The presence of the following file:
    <system folder>\wbem\proquota.exe

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 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 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 web pages
Exercise caution with links to web pages 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: Sep 08, 2009
This entry was updated on: Apr 17, 2011

This threat is also detected as:
No known aliases