Win32/Cypaux is a multi-component family of trojans used to compromise machines and use them in various ways at the attacker's will. This could include using the affected machine to send spam, distribute malware, and proxy malicious traffic. The family consists of downloading, proxy and backdoor components. The backdoor component may be used to create Gmail and MyYearBook accounts, that can be used for sending spam, links and other malicious content.
Installation
TrojanDownloader Component
The initial component used for establishing this family on an affected machine is TrojanDownloader:Win32/Cypaux.
When executed, this component modifies the registry to ensure that its executable runs at each Windows start:
Adds value: "Java S1"
With data: "<original execution location>"
To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\Run
Proxy Component
After being downloaded by TrojanDownloader:Win32/Cypaux, TrojanProxy:Win32/Cypaux drops the following files:
- %temp%\psvr32.exe - detected as Program:Win32/TinyProxy
- %temp%\_pconfig.cfg - detected as TrojanProxy:Win32/Cypaux!ini
It then modifies the registry to ensure that its executable runs at each Windows start:
Sets value: "WinProx32_1"
With data: "<original execution location>"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Sets value: "WinProx32_1"
With data: "<original execution location>"
To subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Backdoor Component
After being downloaded by TrojanDownloader:Win32/Cypaux, Backdoor:Win32/Cypaux modifies the following registry entry to ensure that its executable runs at each Windows start:
Sets value: "Java Syncro"
With data: "<original execution location>"
To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\Run
Payload
Downloads and Executes Arbitrary Files - TrojanDownloader Component
TrojanDownloader:Win32/Cypaux contacts the following URL:
http://66.90.101.177/***/****List.php
in order to download a list of files to download. At the time of writing, these files were detected as variants of Backdoor:Win32/Cypaux and TrojanProxy:Win32/Cypaux.
*Note: this URL has been modified
Establishes Proxy - Proxy Component
TrojanProxy:Win32/Cypaux is a trojan that creates a proxy on an affected machine. It is downloaded to an affected machine by TrojanDownloader:Win32/Cypaux. Proxy servers may be used by attackers in order to hide the origin of malicious activity.
TrojanProxy:Win32/Cypaux opens a socks proxy on TCP ports 35585 and 32947. Once established, it contacts the ophyemaweito.com domain to register the IP address of the affected machine and the ports being used by the proxy server.
Backdoor Functionality - Backdoor Component
Backdoor:Win32/Cypaux is a trojan that allows unauthorized access and control of an affected machine, Its primary purpose appears to be to create dummy accounts on popular email and social networking sites that can then be utilized by its controller.
Once installed, Backdoor:Win32/Cypaux contacts IP 66.90.101.177 in order to receive commands. This backdoor can be instructed to create Gmail and MyYearBook accounts, which can the be used to send spam messages and malicious links. Messages to be sent are obtained from the remote server.
Backdoor:Win32/Cypaux randomly generates characteristics for fake profiles using information obtained from the temp file %temp%\~allinfo.txt.
At the time of writing, only female profiles were being created using various pictures.
Modifies System Security Settings - Backdoor and Proxy Components
TrojanProxy:Win32/Cypaux modifies the following registry entry in order to add %temp%\psvr32.exe (Program:Win32/TinyProxy) to the Windows Firewall Authorized Applications list:
Sets value: "%temp%\psvr32.exe"
With data: "%temp%\psvr32.exe:*:enabled:winsvrhost32"
To subkey: HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
Backdoor:Win32/Cypaux makes a similar modification to add itself to the Authorized Applications list:
Sets value: "<original execution location>"
With data: "<original execution filename>:*:enabled:windows time synchronization"
To subkey: HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
Additional Information
Win32/Cypaux may create the following temporary files in the %temp% directory for its own use:
curl.exe
~allinfo.txt
Analysis by Matt McCormack
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
Click Start, and click Control Panel.
Click Security.
Click Turn Windows Firewall on or off.
Select On.
Click OK.
To turn on the Internet Connection Firewall in Windows XP
Click Start, and click Control Panel.
Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
Click Change Windows Firewall Settings.
Select On.
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
Click Start, and click Control Panel.
Click System and Maintainance.
Click Windows Updates.
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
Click Start, and click Control Panel.
Click System.
Click Automatic Updates.
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.
