WORM_SDBOT.BOA

Malware type: Worm

Aliases: Backdoor.Win32.IRCBot.ck (Kaspersky), W32/Sdbot.worm.gen.bj (McAfee), W32.IRCBot (Symantec), Worm/IrcBot.CK (Avira), W32/Sdbot-Fam (Sophos),

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 95, 98, ME, NT, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

Upon execution, this memory-resident worm drops a copy of itself in the Windows system folder as the file DOWNITE.EXE. It then creates registry entries to enable its automatic execution at every system startup.

This worm spreads via network shares. It gathers any available lists of user names and passwords from an affected system. It then searches for and lists down certain shared folders, where it drops a copy of itself by using the gathered information.

This worm also has backdoor capabilities. It opens various ports, allowing a remote user to access and perform malicious commands on an affected machine. The said routine provides remote users virtual control over affected systems, thus compromising system security.

For additional information about this threat, see:

Description created: Jul. 7, 2005 8:11:46 PM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 38,400 Bytes

Ports used: Varies

Initial samples received on: Jul 2, 2005

Compression type: FSG, Morphine

Payload 1: Compromises system security

Trigger condition 1: Upon execution

Details:

Installation and Autostart Techniques

Upon execution, this memory-resident worm drops a copy of itself in the Windows system folder as the file DOWNITE.EXE.

It creates the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\RunServices
DownNow = "downite.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\Run
DownNow = "downite.exe"

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run
DownNow = "downite.exe"

Network Propagation

This worm spreads via network shares. It gathers any available lists of user names and passwords from an affected system. It then searches for and lists down the following shared folders, where it drops a copy of itself by using the gathered information:

  • ADMIN$\system32
  • C$
  • C$\Documents and Settings\All Users\Documents
  • C$\Shared
  • C$\Windows\system32
  • C$\WINNT\system32
  • IPC$

Backdoor Capabilities

This worm acts as a server program controlled by an Internet Relay Chat (IRC) bot. It opens various ports and connects to an IRC server. It then joins an IRC channel.

Once connected, this server program receives commands from the IRC bot. These commands are used to control the target system and the behavior of the server program. These commands include the following:

  • Perform an IRC command
  • Download a file
  • Update itself

Other Details

This worm runs on Windows 95, 98, ME, NT, 2000, and XP.

Analysis By: Ricardo C. Robielos III

Revision History:

First pattern file version: 2.712.10
First pattern file release date: Jul 02, 2005

SOLUTION


Minimum scan engine version needed: 7.500

Pattern file needed: 3.632.04

Pattern release date: Aug 2, 2006


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:

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.BOA.

Trend Micro customers need to download the latest 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.

  1. Open Windows Task Manager.
    � On Windows 95, 98, and ME, press
    CTRL%20ALT%20DELETE
    � On Windows NT, 2000, and XP, 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 95, 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

Removing Autostart Entries from the Registry

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

If the registry entries 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>RunServices
  3. In the right panel, locate and delete the entry:
    DownNow = "downite.exe"
  4. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Run
  5. In the right panel, locate and delete the entry:
    DownNow = "downite.exe"
  6. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Run
  7. In the right panel, locate and delete the entry:
    DownNow = "downite.exe"
  8. Close Registry Editor.

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

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




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