WORM_SDBOT.CFT

Malware type: Worm

Aliases: Backdoor.Win32.SdBot.cxq (Kaspersky), Backdoor.Sdbot (Symantec), Worm/SdBot.432128.2 (Avira), Mal/Generic-A (Sophos),

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 98, ME, NT, 2000, XP, Server 2003

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

This worm drops a copy of itself as APPCONTROL.EXE in the Windows system folder. It also drops HPDRIVER.SYS, which is detected by Trend Micro as TROJ_ROOTKIT.N, in the same folder.

It spreads by dropping a copy of itself in accessible network shares. It may also spread by taking advantage of machines vulnerable to the following Windows exploits:

  • The RPC/DCOM vulnerability, which allows an attacker to gain full access and execute any code on a target machine by sending a malformed packet to the DCOM service. It uses the RPC TCP port 135. More information on this vulnerability is found in Microsoft Security Bulletin MS03-026.

  • The ASN.1 Library Bitstring Heap Overflow vulnerability is due to an unchecked buffer in the Microsoft ASN.1 library. An attacker or a specially designed malware can cause this buffer to overflow and execute code with system privileges on affected systems. With the ability to execute code with system privileges, the attacker or the malware may install programs, view and modify data, and create new accounts with full privileges. This vulnerability is discussed in detail in Microsoft Security Bulletin MS04-007.

  • The Windows LSASS vulnerability, which is a buffer overrun that allows remote code execution and enables a malicious user to gain full control of the affected system. This vulnerability is discussed in detail in Microsoft Security Bulletin MS04-011.

This worm opens a random port and connects to an Internet Relay Chat (IRC) server. Once connected, it joins a specific channel, where it listens for commands from a remote user. It executes the said commands locally on affected machines.

It terminates different processes, which are related to previously hot malware programs like WORM_MSBLAST, WORM_NETSKY, and WORM_BAGLE.

It performs a denial of service attack against target sites using different flood methods.

This worm may cause a blue screen error while registering TROJ_ROOTKIT.N on systems running on Windows Server 2003.

For additional information about this threat, see:

Description created: Sep. 14, 2005 8:04:30 PM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: ~64,000 Bytes

Ports used: Random

Initial samples received on: Sep 14, 2005

Compression type: UPX

Vulnerability used:  (MS04-007) ASN.1 Vulnerability Could Allow Code Execution, (MS04-011) Security Update for Microsoft Windows (835732), (MS03-026) Buffer Overrun In RPC Interface Could Allow Code Execution

Related toTROJ_ROOTKIT.N

Payload 1: Compromises system security

Payload 2: Terminates processes

Payload 3: Performs a denial of service attack

Payload 4: lowers the affected system's firewall and security settings

Payload 5: Disables specific services

Details:

Installation and Autostart

Upon execution, this worm drops a copy of itself as APPCONTROL.EXE in the Windows system folder. It also drops HPDRIVER.SYS, which is detected by Trend Micro as TROJ_ROOTKIT.N, in the same folder.

It creates the following autostart entry to ensure its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Security Center = "AppControl.exe"

It also adds itself as a service using the display name Application Control Software, this service is used by the worm as an autostart technique.

Other Registry Modifications

This worm also modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\
WindowsFirewall\DomainProfile
EnableFirewall = "dword:00000000"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\
WindowsFirewall\StandardProfile
EnableFirewall = "dword:00000000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanserver\parameters
AutoShareWks = "dword:00000000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanserver\parameters
AutoShareServerv = "dword:00000000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanworkstation\parameters
AutoShareWks = "dword:00000000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanworkstation\parameters
AutoShareServer = "dword:00000000"

(Note: The default value of the said registry entries is user-defined.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\WindowsUpdate\Auto Update
AUOptions = "dword:00000001"

(Note: The default value of the said entry is "dword:00000002".)

HKEY_LOCAL_MACHINE\SYSTEM\
CurrentControlSet\Control
WaitToKillServiceTimeout = "7000"

(Note: The default value of the said entry is "20000".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
Start = "dword:00000004"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RemoteRegistry
Start = "dword:00000004"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Messenger
Start = "dword:00000004"

(Note: The default value of the said entry is "dword:00000002".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TlntSvr
Start = "dword:00000004"

(Note: The default value of the said entry is "dword:00000003".)

It lowers affected machines' firewall and security center settings by modifying the following entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
AntiVirusDisableNotify = "dword:00000001"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
FirewallDisableNotify = "dword:00000001"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
AntiVirusOverride = "dword:00000001"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
FirewallOverride = "dword:00000001"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
UpdatesDisableNotify = "dword:00000001"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate
DoNotAllowXPSP2 = "dword:00000001"

(Note: The default value of the mentioned registry entries is "dword:00000000".)

Network Propagation and Exploits

This worm spreads by dropping a copy of itself in the following network shares:

  • ADMIN$
  • ADMIN$\system32
  • C$\Windows\system32
  • C$\WINNT\system32
  • D$\Windows\system32
  • D$\WINNT\system32
  • IPC$

This worm may also spread by taking advantage of machines vulnerable to the following Windows exploits:

  • The RPC/DCOM vulnerability, which allows an attacker to gain full access and execute any code on a target machine by sending a malformed packet to the DCOM service. It uses the RPC TCP port 135. More information on this vulnerability is found in Microsoft Security Bulletin MS03-026.

  • The ASN.1 Library Bitstring Heap Overflow vulnerability is due to an unchecked buffer in the Microsoft ASN.1 library. An attacker or a specially designed malware can cause this buffer to overflow and execute code with system privileges on affected systems. With the ability to execute code with system privileges, the attacker or the malware may install programs, view and modify data, and create new accounts with full privileges. This vulnerability is discussed in detail in Microsoft Security Bulletin MS04-007.

  • The Windows LSASS vulnerability, which is a buffer overrun that allows remote code execution and enables a malicious user to gain full control of the affected system. This vulnerability is discussed in detail in Microsoft Security Bulletin MS04-011.

Backdoor Capabilities

This worm opens a random port and connects to an Internet Relay Chat (IRC) server. Once connected, it joins a specific channel, where it listens for commands from a remote user. It executes the said commands, which are the following, locally on affected machines:

  • Capture screenshots
  • Clone itself
  • Delete files
  • Download and execute files
  • Download files via FTP
  • Gather the following information, which it sends to a remote user via email:
    • Connection type
    • CPU speed
    • Current user
    • Free memory size
    • IP address
    • Platform
    • System time
    • Total memory size
  • Join another IRC server using a new nickname
  • Launch denial of service (DoS) flood attacks using the ICMP and SYN methods
  • List processes
  • List shares on a system
  • Log keystrokes
  • Log system information
  • Send TCP and UDP packets
  • Update itself

Process Termination

This worm terminates the following processes if found running in the memory:

  • Bagle.a
  • Bagle.j
  • Bagle.k
  • Bagle.v
  • bbeagle.exe
  • d3dupdate.exe
  • irun4.exe
  • Microsoft Inet Xp..
  • MSBLAST.exe
  • mscvb32.exe
  • Mydoom.h
  • Netsky.r
  • PandaAVEngine
  • PandaAVEngine.exe
  • Penis32.exe
  • Sobig.c
  • ssate.exe
  • sysinfo.exe
  • System MScvb
  • TaskMon
  • taskmon.exe
  • teekids.exe
  • W32.Blaster
  • W32.Blaster.B
  • W32.Blaster.C
  • windows auto update

The said processes are related to previously hot malware programs namely WORM_MSBLAST, WORM_NETSKY, and WORM_BAGLE.

Denial of Service Attack

This worm performs a denial of service attack against target sites using any of the following flood methods:

  • ACK flood
  • ICMP flood
  • SYN flood
  • UDP flood

Other Details

This worm may cause a blue screen error while registering TROJ_ROOTKIT.N on systems running on Windows Server 2003.

This worm runs on Windows 98, ME, NT, 2000, XP, and Server 2003.

Analysis By: Kerr Brynner C. Ang

Revision History:

First pattern file version: 5.232.11
First pattern file release date: Apr 22, 2008
 
Oct 4, 2005 - Modified Virus Report

SOLUTION


Minimum scan engine version needed: 7.000

Pattern file needed: 5.513.00

Pattern release date: Sep 1, 2008


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

Note: To fully remove all associated malware, perform the clean solution for TROJ_ROOTKIT.N.

Identifying the Malware Program

To remove this malware, first identify the malware program.

  1. Scan your system with your Trend Micro antivirus product.
  2. NOTE the path and file name of all files detected as WORM_SDBOT.CFT.

Trend Micro customers need to download the latest virus pattern file before scanning their system. Other users can use Housecall, Trend Micro's online virus scanner.

Terminating the Malware Program

This procedure terminates the running malware process. You will need the name(s) of the file(s) detected earlier.

If the process you are looking for is not in the list displayed by Task Manager, proceed to the succeeding solution set.

  1. Open Windows Task Manager.
    • On Windows 98 and ME, press
    CTRL%20ALT%20DELETE
    • On Windows NT, 2000, XP, and Server 2003, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the malware file(s) detected earlier.
  3. Select one of the detected files, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. Do the same for all detected malware files in the list of running processes.
  5. To check if the malware process has been terminated, close Task Manager, and then open it again.
  6. Close Task Manager.

*NOTE: On systems running Windows 98 and ME, Windows Task Manager may not show certain processes. You can use a third party process viewer such as Process Explorer to terminate the malware process. Otherwise, continue with the next procedure, noting additional instructions. If you were not able to terminate the malware process as described in the previous procedure, restart your system.

Editing the Registry

This malware modifies the system's registry. Users affected by this malware may need to modify or delete specific registry keys or entries. For detailed information regarding registry editing, please refer to the following articles from Microsoft:

  1. HOW TO: Backup, Edit, and Restore the Registry in Windows 95, Windows 98, and Windows ME
  2. HOW TO: Backup, Edit, and Restore the Registry in Windows NT 4.0
  3. HOW TO: Backup, Edit, and Restore the Registry in Windows 2000
  4. HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and 2003

Removing Autostart Entry from the Registry

Removing autostart entries from the registry prevents the malware from executing at startup.

If the registry entry below are not found, the malware may not have executed as of detection. If so, proceed to the succeeding solution set.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    Security Center = "AppControl.exe"

Restoring Security Update Center Settings

This malware modifies the Firewall, Antivirus, and Update function settings for systems running on Windows XP SP2. Perform the instructions below to reactivate these functions.

If you do not have Windows XP SP2 installed on your system, please proceed to the succeeding solution set.

  1. Still in the Registry Editor, in the left panel, locate the following registry key:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Security Center
  2. In the right panel, locate and delete the entries:
    • FirewallDisableNotify = "dword:00000001"
    • UpdatesDisableNotify = "dword:00000001"
    • AntiVirusDisableNotify = "dword:00000001"
    • AntiVirus Override = "dword:00000001"
    • Firewall Override = "dword:00000001"

Restoring Other Modified Registry Entries

  1. Still in the Registry Editor, in the left panel, double click the following: HKEY_LOCAL_MACHINE>SOFTWARE>Policies>Microsoft>
    WindowsFirewall>DomainProfile
  2. In the right panel, locate and delete the following entry:
    EnableFirewall = "dword:00000000"
  3. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Policies>Microsoft>
    WindowsFirewall>StandardProfile
  4. In the right panel, locate and delete the following entry:
    EnableFirewall = "dword:00000000"
  5. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
    Services>lanmanworkstation>parameters
  6. In the right panel, locate and delete the following entries:
    • AutoShareServer = "dword:00000000"
    • AutoShareWks = "dword:00000000"
  7. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
    Services>lanmanserver>parameters
  8. In the right panel, locate and delete the following entries:
    • AutoShareServer = "dword:00000000"
    • AutoShareWks = "dword:00000000"
  9. li>In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>
    CurrentVersion>WindowsUpdate>Auto Update
  10. In the right panel, locate the entry:
    AUOptions = "dword:00000001"
  11. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    AUOptions = "dword:00000002"
  12. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
    Control
  13. In the right panel, locate the entry:
    WaitToKillServiceTimeout = "7000"
  14. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    WaitToKillServiceTimeout = "20000"
  15. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>System>CurrentControlSet>
    Control>wscsvc
  16. In the right panel, locate the entry:
    Start = "dword:00000004"
  17. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    Start = "dword:00000002"
  18. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>System>CurrentControlSet>
    Services>Messenger
  19. In the right panel, locate the entry:
    Start = "dword:00000004"
  20. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    Start = "dword:00000002"
  21. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>System>CurrentControlSet>
    Services>RemoteRegistry
  22. In the right panel, locate the entry:
    Start = "dword:00000004"
  23. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    Start = "dword:00000002"
  24. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>System>CurrentControlSet>
    Services>TlntSvr
  25. In the right panel, locate the entry:
    Start = "dword:00000004"
  26. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    Start = "dword:00000003"
  27. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Policies>
    Microsoft>Windows>WindowsUpdate
  28. In the right panel, locate and delete the following:
    DoNotAllowXPSP2 = "dword:00000001"

Restoring EnableDCOM and RestrictAnonymous Registry Entries

This malware modifies EnableDCOM and RestrictAnonymous registry entries to a certain value. To know more about restoring these registries to their original values, please refer to these articles:

  1. COM security frequently asked questions
  2. How to disable DCOM support in Windows
  3. How to Use the RestrictAnonymous Registry Value in Windows 2000
  4. The "RestrictAnonymous" Registry Value May Break the Trust to a Windows 2000 Domain

To restore this entry to its default value, please perform the following instructions:

  1. Still in the Registry Editor, in the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Ole
  2. In the right panel, locate the entry:
    EnableDCOM = "N"
  3. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    EnableDCOM = "Y"
  4. Close Registry Editor.

Disabling Malware Service

This stops the running malware service on systems running Windows NT, 2000, XP, and Server 2003.

  1. Open a command prompt window. Click Start>Run, type CMD, and then press the Enter.
  2. At the command prompt, type the following:
    NET STOP Application Control Software
  3. Press Enter. A message should indicate that the service has been stopped successfully.
  4. Close the command prompt window.

Important Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected systems.

Users running other Windows versions can proceed with the succeeding procedure set(s).

Running Trend Micro Antivirus

If you are currently running on safe mode, please restart your system normally before performing the following solution.

Scan your system with Trend Micro antivirus and delete files detected as WORM_SDBOT.CFT. To do this, Trend Micro customers must download the latest virus pattern file and scan their system. Other Internet users can use HouseCall, Trend Micro's online virus scanner.

Applying Patches

This malware exploits known vulnerabilities in Windows. Download and install the fix patch supplied by Microsoft in the following pages:

(*Note: The fix patch found in Microsoft Security Bulletin MS03-039 overrides the fix patch in Microsoft Security Bulletin MS03-026 and covers additional vulnerabilities. Thus, affected users, even those who have already applied MS03-026 to their respective machines, are advised to download this updated patch.)

Refrain from using this product until the appropriate patch has been installed. Trend Micro advises users to download critical patches upon release by vendors.


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