Discovered: February 02, 2006
Updated: February 13, 2007 12:51:00 PM
Type: Worm
Systems Affected: Windows


W32.Kiman.A is a worm that has distributed denial of service and back door capabilities. The worm spreads by copying itself to network shares protected by weak passwords or by exploiting computer vulnerabilities.

Note: Virus definitions dated prior to February 2, 2006 may detect this as W32.Spybot.Worm.

Antivirus Protection Dates

  • Initial Rapid Release version February 02, 2006
  • Latest Rapid Release version February 02, 2006
  • Initial Daily Certified version February 02, 2006
  • Latest Daily Certified version February 02, 2006
  • Initial Weekly Certified release date February 08, 2006

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Candid Wueest

Discovered: February 02, 2006
Updated: February 13, 2007 12:51:00 PM
Type: Worm
Systems Affected: Windows


When W32.Kiman.A is executed, it performs the following actions:

  1. Checks for the presence of a debugger and terminates itself if one is found on the compromised computer. The same action is taken if it detects that it's running in a VMware virtual machine.

  2. Copies itself as %System%\dnsresolver.exe.

    Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

  3. Adds the value:

    "Domain Name Resolve Service" = "dnsresolver.exe"

    to the registry subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\OLE
    HKEY_LOCAL_MACHINE\Software\Microsoft\OLE
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\
    RunServices
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    RunServices
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

    so that it runs every time Windows starts

  4. Modifies the value:

    "EnableDCOM" = "N"

    in the registry subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\OLE

    to disable DCOM.

  5. Modifies the value:

    "restrictanonymous" = "1"

    in the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

    to restrict null sessions.

  6. Creates the following files which are used to modify registry keys:

    • %SystemDrive%\a.bat
    • %Temp%\1.reg

      Note:
    • %SystemDrive% is a variable that refers to the drive on which Windows is installed. By default, this is drive C.
    • %Temp% is a variable that refers to the Windows temporary folder. By default, this is C:\Windows\TEMP (Windows 95/98/Me/XP) or C:\WINNT\Temp (Windows NT/2000).

  7. Modifies the value:

    "TransportBindName" =" "

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Parameters

    to change the system configuration.

  8. Modifies the value:

    "Start" = "4"

    to the registry subkeys:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wuauserv
    HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wscsvc

    to change the system configuration.

  9. Modifies the value:

    "EnableRemoteConnect" = "N"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole

    to change the system configuration.

  10. Modifies the value:

    "Enabled" = "0"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\
    SecurityProviders\SCHANNEL\Protocols\PCT1.0\Server

    to change the system configuration.

  11. Modifies the values:

    "AutoShareWks" = "0"
    "AutoShareServer" = "0"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
    lanmanserver\parameters

    to change the system configuration.

  12. Modifies the values:

    "NameServer" = ""
    "ForwardBroadcasts" = "0"
    "IPEnableRouter" = "0"
    "Domain" = ""
    "SearchList" = ""
    "UseDomainNameDevolution" = "1"
    "EnableICMPRedirect" = "0"
    "DeadGWDetectDefault" = "1"
    "DontAddDefaultGatewayDefault" = "0"
    "EnableSecurityFilters" = "1"
    "AllowUnqualifiedQuery" = 0
    "PrioritizeRecordData" = "1"
    "TCP1320Opts" = "3"
    "KeepAliveTime" = "23280"
    "BcastQueryTimeout" = "2ee"
    "BcastNameQueryCount" = "1"
    "CacheTimeout"=ea60
    "Size/Small/Medium/Large" = "3"
    "LargeBufferSize" = "1000"
    "SynAckProtect" = "2"
    "PerformRouterDiscovery" = "0"
    "EnablePMTUBHDetect" = "0"
    "FastSendDatagramThreshold " = "400"
    "StandardAddressLength " = "18"
    "DefaultReceiveWindow " = "4000"
    "DefaultSendWindow" = "4000"
    "BufferMultiplier" = "200"
    "PriorityBoost" = "2"
    "IrpStackSize" = "4"
    "IgnorePushBitOnReceives" = "0"
    "DisableAddressSharing" = "0"
    "AllowUserRawAccess" = "0"
    "DisableRawSecurity" = "0"
    "DynamicBacklogGrowthDelta" = "32"
    "FastCopyReceiveThreshold" = "400"
    "LargeBufferListDepth" = "a"
    "MaxActiveTransmitFileCount" = "2"
    "MaxFastTransmit" = "40"
    "OverheadChargeGranularity" = "1
    "SmallBufferListDepth" = "20"
    "SmallerBufferSize" = "80"
    "TransmitWorker" = "20"
    "DNSQueryTimeouts" = "hex(7):31,00,00,00,32,00,00,00,32,00,00,00,34,00,00,00,38,00,00,00,30,00,00,00,00,00"
    "DefaultRegistrationTTL" = "14
    "DisableReplaceAddressesInConflicts" = "0"
    "DisableReverseAddressRegistrations" = "1"
    "UpdateSecurityLevel" = "0"
    "DisjointNameSpace" = "1"
    "QueryIpMatching" = "0"
    "NoNameReleaseOnDemand" = "1"
    "EnableDeadGWDetect" = "0"
    "EnableFastRouteLookup" = "1"
    "MaxFreeTcbs" = "7d0"
    "MaxHashTableSize" = "800"
    "SackOpts" = "1"
    "Tcp1323Opts" = "3"
    "TcpMaxDupAcks" = "1"
    "TcpRecvSegmentSize" = "585"
    "TcpSendSegmentSize" = "585"
    "TcpWindowSize" = "7d200"
    "DefaultTTL" = "30"
    "TcpMaxHalfOpen" = "4b"
    "TcpMaxHalfOpenRetried" = "50"
    "TcpTimedWaitDelay" = "0"
    "MaxNormLookupMemory" = "30d40"
    "FFPControlFlags" = "1"
    "FFPFastForwardingCacheSize" = "30d40"
    "MaxForwardBufferMemory" = "19df7"
    "MaxFreeTWTcbs" = "7d0"
    "GlobalMaxTcpWindowSize" = "7d200"
    "EnablePMTUDiscovery" = "1"
    "ForwardBufferMemory" = "19df7"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

    to change the system configuration.

  13. Modifies the values:

    "MaxConnectionsPer1_0Server" = "50"
    "MaxConnectionsPerServer" = "50"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings

    to change the system configuration.

  14. Attempts to open a back door by connecting to an IRC channel through TCP port 443 on the enz.fulame.biz domain.

  15. Listens for commands that allow the remote attacker to perform the following actions:

    • Download and execute files
    • List, stop, and start processes and threads
    • Launch ACK, SYN, UDP, and ICMP Denial of Service (DoS) attacks
    • Perform port redirection
    • Send files over IRC
    • Send email using its own SMTP engine
    • Start a local HTTP, FTP, or TFTP server
    • Search for files on the compromised computer
    • Access network shares and copy itself to those network shares
    • Scan the network for vulnerable hosts by means of port scanning
    • Intercept packets on the local area network
    • Flush the DNS and ARP caches
    • Open a command shell on the infected computer
    • Add and delete network shares and disable DCOM
    • Reboot the infected computer

  16. May scan for computers and try to exploit one of the following vulnerabilities:

  17. Attempts to spread to randomly generated IP addresses by copying itself to network shares with weak passwords.


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.

Writeup By: Candid Wueest

Discovered: February 02, 2006
Updated: February 13, 2007 12:51:00 PM
Type: Worm
Systems Affected: Windows


Removal using the W32.Kiman.A Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of W32.Kiman.A. Use this removal tool first, as it is the easiest way to remove this threat.

Manual Removal:


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Run a full system scan and delete all the files detected.
  4. Delete any values added to the registry.
  5. Reenable the SharedAccess service (Windows 2000/XP only).
For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
Note:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions:
    • If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.
    • If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

3. To scan for and delete the infected files
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected, click Delete.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode . Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.


4. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  4. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\OLE
    HKEY_LOCAL_MACHINE\Software\Microsoft\OLE
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\
    RunServices
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    RunServices
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

  5. In the right pane, delete the value:

    "Domain Name Resolve Service" = "dnsresolver.exe"

  6. Exit the Registry Editor.

5. To reenable the SharedAccess service (Windows 2000/XP only)
The SharedAccess service is responsible for maintaining Internet Connection Sharing and the Windows Firewall/Internet Connection Firewall applications in Windows. (The presence and names of these applications vary depending on the operating system and service pack you are using.) To protect your computer and maintain network functionality, re-enable this service if you are using any of these programs.


Windows XP Service Pack 2
If you are running Windows XP with Service Pack 2 and are using the Windows Firewall, the operating system will alert you when the SharedAccess service is stopped, by displaying an alert balloon saying that your Firewall status is unknown. Perform the following steps to ensure that the Windows Firewall is re-enabled:
  1. Click Start > Control Panel.

  2. Double-click the Security Center.

  3. Ensure that the Firewall security essential is marked ON.

    Note: If the Firewall security essential is marked on, your Windows Firewall is on and you do not need to continue with these steps.

    If the Firewall security essential is not marked on, click the "Recommendations" button.

  4. Under "Recommendations," click Enable Now. A window appears telling you that the Windows Firewall was successfully turned on.

  5. Click Close, and then click OK.

  6. Close the Security Center.


Windows 2000 or Windows XP Service Pack 1 or earlier
Complete the following steps to re-enable the SharedAccess service:
  1. Click Start > Run.
  2. Type services.msc

    Then click OK.

  3. Do one of the following:
    • Windows 2000: Under the Name column, locate the "Internet Connection Sharing (ICS)" service and double-click it.
    • Windows XP: Under the Named column, locate the "Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)" service and double-click it.

  4. Under "Startup Type:", select "Automatic" from the drop-down menu.

  5. Under "Service Status:", click the Start button.

  6. Once the service has completed starting, click OK.

  7. Close the Services window.



Writeup By: Candid Wueest