WORM_RBOT.APK

Malware type: Worm

Aliases: Backdoor.Win32.Rbot.bgl (Kaspersky), W32/Sdbot.worm (McAfee), W32.Spybot.Worm (Symantec), Worm/Rbot.369664.2 (Avira), W32/Rbot-Fam (Sophos),

In the wild: Yes

Language: English

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

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

Worms are malicious programs that are able to replicate independently across a network, through email, Internet Relay Chat (IRC), or Peer-to-peer applications. They do not infect other files on a computer.

This variant of the WORM_RBOT family mainly propagate through network shares. Upon execution, it drops a copy of itself as the file DNSWN.EXE in the Windows system folder. It then attempts to place copies of itself into accessible shared folders across a network. It uses its own compiled list of user names and passwords in order to access shared folders that are password protected.

It also takes advantage of the following Windows vulnerabilities to propagate:

  • Buffer Overflow in SQL Server 2000
  • IIS5/WEBDAV vulnerability
  • RPC DCOM buffer overflow vulnerability

For more information regarding these vulnerabilities, please refer to the following Microsoft Web page(s):

It is also able to detect systems installed with DameWare, as well as those affected by the variants of the following malware:

  • BKDR_KUANG
  • BKDR_NETDEVIL
  • BKDR_OPTIX
  • WORM_BAGLE
  • WORM_MYDOOM
  • WORM_SASSER

It also has backdoor capabilities. It comes with a built-in Internet Relay Chat (IRC) bot that allows it to connect to an IRC server. The IRC bot then runs in the background and waits for commands from a remote user. An IRC bot is an automated software program that can execute certain commands when it receives specific input (usually from the malwares creator), thus allowing a remote user to manipulate infected machines. Once connected, the remote user may gain virtual control of the affected system.

Through this backdoor, the remote user can command the affected system to conduct Distributed Denial of Service (DDoS) attacks, steal the CD keys from certain PC games, and other malicious actions.

For additional information about this threat, see:

Description created: Feb. 23, 2005 12:41:16 PM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 259,570 Bytes

Ports used: Random

Initial samples received on: Feb 23, 2005

Compression type: ExeStealth

Vulnerability used:  (MS03-007) Unchecked Buffer In Windows Component Could Cause Server Compromise (815021), (MS03-026) Buffer Overrun In RPC Interface Could Allow Code Execution, (MS02-061) Elevation of Privilege in SQL Server Web Tasks (Q316333)

Family:  WORM_RBOT

Payload 1: Compromises system security

Payload 2: Steals information

Payload 3: Performs DDoS attacks

Details:

Installation and Autostart Techniques

Worms are malicious programs that are able to replicate independently across a network, through email, Internet Relay Chat (IRC), or Peer-to-peer applications. They do not infect other files on a computer.

This variant of the WORM_RBOT family mainly propagate through network shares. Upon execution, it drops a copy of itself as the file DNSWN.EXE in the Windows system folder. It then attempts to place copies of itself into accessible shared folders across a network.

It creates the following registry entries to ensure it automatically executes during every Windows startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Run
Dns Server = "dnswn.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\RunServices
Dns Server = "dnswn.exe"

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run
Dns Server = "dnswn.exe"

Other Registry Modifications

This worm also modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\OLE
EnableDCOM = �N�

(Note: The default value for this registry entry is �Y�.)

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA
Restrictanonymous = "dword:00000001"

(Note: The default value for this registry entry is �00000000�.)

Propagation via Network Shares

This worm propagates by dropping copies of itself into accessible network shares. It may search for, and drop copies of itself into the following folders:

  • Admin$\system32\
  • C$\Windows\system32
  • C$\WINNT\system32\
  • Print$\

It attempts to use an extensive list of compiled user names and passwords in order to access shared folders that are password protected.

Exploits

This worm takes advantage of the following Windows vulnerabilities to propagate:

  • Buffer Overflow in SQL Server 2000
  • IIS5/WEBDAV vulnerability
  • RPC DCOM buffer overflow vulnerability

For more information regarding these vulnerabilities, please refer to the following Microsoft Web page(s):

Backdoor Routine

This worm also has backdoor capabilities. It comes with a built-in Internet Relay Chat (IRC) bot that allows it to connect to a specific IRC Server. It then waits for commands from a remote user. An IRC bot is an automated software program that can execute certain commands when it receives specific input (usually from the malware�s creator), thus allowing a remote user to manipulate infected machines. Once connected, the remote user may gain virtual control of the affected system. The remote user can then execute the following malicious actions:

  • Add/Delete/List network shares
  • Create/List/Delete user accounts
  • Download/Search/Delete files
  • Enable/Disable Anonymous login
  • Enable/Disable DCOM
  • Execute/List/Terminate processes
  • Flush DNS Cache
  • Get Clipboard data
  • Get Windows logon password
  • Get system and network information
  • List/Start/Stop service
  • Open FTP server
  • Open a remote command shell
  • Perform basic FTP commands
  • Perform basic IRC commands
  • Perform packet sniffing for specific strings
  • Scan ports
  • Send email
  • Start up proxy server

Denial of Service Attack

Denial of Service (DoS) attacks disrupt the normal functions of a targeted Web site or group of Web sites, creates massive network traffic, and taxes IT infrastructure and resources. DoS attacks typically flood Web sites or servers with requests that may slow down or even crash the target site altogether. Having multiple computers attacking a single site constitute a Distributed Denial of Service (DDoS) attack.

This worm enables malicious users to launch the following types of DDoS attacks against a target site:

  • ICMP flood attack
  • Ping flood attack
  • SYN flood attack
  • TCP flood attack
  • UDP flood attack

Information Theft

This worm steals the CD keys of the following PC games, if they are installed on the system:

  • Battlefield 1942 (Road To Rome)
  • Battlefield 1942 (Secret Weapons of WWII)
  • Battlefield Vietnam
  • Chrome
  • Command and Conquer: Generals
  • Command and Conquer: Generals (Zero Hour)
  • Command and Conquer: Red Alert
  • Command and Conquer: Red Alert 2
  • Command and Conquer: Tiberian Sun
  • Counter-Strike (Retail)
  • FIFA 2002
  • FIFA 2003
  • Freedom Force
  • Global Operations
  • Gunman Chronicles
  • Half-Life
  • Hidden & Dangerous
  • IG2
  • IGI 2: Covert Strike
  • Industry Giant 2
  • James Bond 007: Nightfire
  • Legends of Might and Magic
  • Medal of Honor: Allied Assault: Breakthrough
  • Medal of Honor: Allied Assault: Spearhead
  • NHL 2002
  • NHL 2003
  • NOX
  • Nascar Racing 2002
  • Nascar Racing 2003
  • Need For Speed Hot Pursuit 2
  • Need For Speed: Underground
  • Neverwinter Nights
  • Neverwinter Nights (Hordes of the Underdark)
  • Neverwinter Nights (Shadows of Undertide)
  • Rainbow Six III
  • Shogun: Total War: Warlord Edition
  • Soldier of Fortune II - Double Helix
  • Soldiers Of Anarchy
  • The Gladiators
  • The Road to Rome
  • Unreal Tournament 2003
  • Unreal Tournament 2004

It also steals the Windows product ID, and is able to conduct keylogging and webcam video capture.

Other Details

This worm is also able to detect systems installed with DameWare, as well as those affected by the variants of the following malware:

  • BKDR_KUANG
  • BKDR_NETDEVIL
  • BKDR_OPTIX
  • WORM_BAGLE
  • WORM_MYDOOM
  • WORM_SASSER

Analysis By: Jhoevine Cago Capicio

Revision History:

First pattern file version: 2.439.06
First pattern file release date: Feb 23, 2005

SOLUTION


Minimum scan engine version needed: 7.500

Pattern file needed: 5.125.00

Pattern release date: Feb 26, 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:

AUTOMATIC REMOVAL INSTRUCTIONS

To automatically remove this malware from your system, please use Trend Micro Damage Cleanup Template / Engine.

MANUAL REMOVAL INSTRUCTIONS

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 all files detected as WORM_RBOT.APK .

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.

Removing Autostart Entries from the Registry

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

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:

  3. HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>Run
  4. In the right panel, locate and delete the entry:

  5. Dns Server = "dnswn.exe"
  6. In the left panel, double-click the following:

  7. HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>RunServices
  8. In the right panel, locate and delete the entry:

  9. Dns Server = "dnswn.exe"
  10. In the left panel, double-click the following:

  11. HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Run
  12. In the right panel, locate and delete the entry:

  13. Dns Server = "dnswn.exe"
  14. Close Registry Editor.

NOTE:If you were not able to terminate the malware process as described in the previous procedure, restart your system.

Restoring Modified Registry Entries

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter. HKEY_LOCAL_MACHINE\Software\Microsoft\OLE
  2. In the left panel, double-click the following:

  3. In the right panel, locate and modify the following registry entry from:

  4. EnableDCOM = "N" to
    EnableDCOM = "Y"
  5. Close Registry Editor.

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

Additional 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_RBOT.APK . 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.

Applying Patches

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

Trend Micro advises users to download critical patches upon release by vendors.




Trend Micro offers best-of-breed antivirus and content-security solutions for your corporate network, small and medium business, mobile device or home PC.