W32.Mandaph

When the worm executes, it may try to delete the following file:
C:\stop

It may check for the presence of the following virtual environments and will not execute if either of the programs are present:

• VMWare
• VirtualPC

It then creates the following file used as an infection marker for the compromised computer:
C:\stop

The worm may then create copies of itself in the following locations:

• %Windir%\system32\drivers\spools.exe
• %UserProfile%\cftmon.exe
• %Windir%\system32\drivers\ctfmun.exe

It may also drop the following additional malicious files on the computer:

• %System%\drivers\sysproc.sys
• %System%\ftpdll.dll

Next, the worm may create some of the following registry entries so that it executes whenever Windows starts:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"ntuser" = "C:\WINDOWS\system32\drivers\spools.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"autoload" = "%UserProfile%\cftmon.exe"
• HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"ntuser" = "C:\WINDOWS\system32\drivers\spools.exe"
• HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"autoload" = "%UserProfile%\cftmon.exe"

It may also modfiy the following registry entries so that it executes whenever Windows starts:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule\"ImagePath" = "C:\WINDOWS\system32\drivers\spools.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile\shell\open\command\"(default)" = "%UserProfile%\cftmon.exe %1 %*"

Next, the worm may modify the values of the following registry entries, possibly to disable some other malware present on the compromised computer:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"Shell" = "Explorer"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"UIHost" = "logonui.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"UserInit" = "%System%\userinit.exe,"

It may create the following registry subkeys in order to register a Browser Helper Object on the computer:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\[RANDOM CLSID]
• HKEY_CLASSES_ROOT\CLSID\[RANDOM CLSID]

The worm may then contact some of the following remote hosts using HTTP in order to download commands and additional files to execute:

• [http://]google-analytics.info/s[REMOVED]
• [http://]atomakayan.biz/s[REMOVED]
• [http://]haydex.info/s[REMOVED]
• [http://]fewfwe.com
• [http://]fewfwe.net
• [http://]58.65.237.65/z[REMOVED]
• [http://]geil-de.info/ad[REMOVED]
• [http://]75.126.83.146/[REMOVED]
• [http://]dns-blabla.org/s[REMOVED]
• [http://]75.127.91.217/l[REMOVED]
• [http://]vvsecurity.cn/upd[REMOVED]
• [http://]winupdate.cn/pat[REMOVED]
• [http://]vipxxxzone.com/css/load[REMOVED]
• [http://]hq-pharma.org[REMOVED]
• [http://]portvn.in[REMOVED]
• [http://]samoeono.cn[REMOVED]
• [http://]conceptinvestin.com/l[REMOVED]
• [http://]inewbusiness.com/te[REMOVED]
• [http://]tatushki.info/b[REMOVED]

The worm then attempts to contact several URLs of the following format:
http://[REMOTE HOST]/[REMOTE PAGE]

Where [REMOTE PAGE] could be one of the following PHP Web pages:

• manda.php
• data.php
• vbs.php

For example:
http://[REMOTE HOST]/manda.php?id=[INFECTED BOT ID]&v=[BOT STRING]&s=[DATA]

Where [INFECTED BOT ID] is a unique numeric ID generated to identify the compromised computer. [BOT STRING] is a unique string that identifies the worm and [DATA] is the data sent by the worm.

It may infect removable drives by searching for the first 16 drive letters starting from C drive.

• %DriveLetter%\autorun.inf
• %DriveLetter%\autorun.exe

It may create the following files to store its data:

• %UserProfile%\mpr.dat
• %UserProfile%\mpr2.dat
• %UserProfile%\cs.dat
• %UserProfile%\update.dat

It may then download and install additional malware on to the compromised computer.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.

Summary