WORM_RBOT.CRD

Malware type: Worm

Aliases: W32.IRCBot (Symantec), Worm/Gaobot.196070 (Avira),

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Infection Channel 1 : Propagates via network shares


Description: 

This worm spreads by dropping and executing a copy of itself in available network shares. It takes advantage of the Windows vulnerabilities whose descriptions are found in the following Microsoft Web pages:

Using a random port, it connects to an Internet Relay Chat (IRC) server and joins a specific channel, where it listens for commands from a remote malicious user. The said commands are executed locally on affected machines.

It performs denial of service (DoS) attacks against target sites using different flood methods. It also terminates certain processes found running in memory.

For additional information about this threat, see:

Description created: Nov. 5, 2005 12:06:17 PM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 61,689 Bytes

Ports used: Random

Initial samples received on: Nov 5, 2005

Compression type: MEW

Vulnerability used:  (MS03-039) Buffer Overrun In RPCSS Service Could Allow Code Execution, (MS05-039) Vulnerability in Plug and Play Could Allow Remote Code Execution and Elevation of Privilege (899588)

Payload 1: Compromises system security

Payload 2: Terminates processes found running in memory

Payload 3: Performs denial of service attacks against target sites

Payload 4: Disables DCOM protocol and restricts anonymous access

Details:

Installation and Autostart Techniques

Upon execution, this worm drops a copy of itself as fqwfeq.exe in the Windows system folder. It sets its file attributes to system, read-only, and hidden to avoid detection.

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunServices
GoOutside = "fqwfeq.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
GoOutside = "fqwfeq.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunServices
GoOutside = "fqwfeq.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
GoOutside = "fqwfeq.exe"

It also creates the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Control\LSA
GoOutside= "fqwfeq.exe"

HKEY_CURRENT_USER\SOFTWARE\Microsoft\OLE
GoOutside= "fqwfeq.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OLE
GoOutside= "fqwfeq.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\LSA
GoOutside= "fqwfeq.exe"

Other Registry Modifications

This worm disables the DCOM protocol and restricts anonymous access to the affected system by modifying the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\OLE
EnableDCOM = "N"

(Note: The default value for the said registry entry is EnableDCOM = "Y".)

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

(Note: Though there is no default value for RestrictAnonymous, it may be modified from the one defined by the user.)

Network Propagation and Exploits

This worm generates IP addresses and spreads by attempting to drop and execute a copy of itself in the following target addresses' default shares:

  • ADMIN$
  • C$
  • D$
  • IPC$

This worm takes advantage of the following Windows vulnerabilities:

  • Buffer Overrun In RPCSS Service Could Allow Code Execution, which is actually 3 security holes found in the Distributed Component Object Model (DCOM) interface within the RPCSS Service. Two of these vulnerabilities compromise system security by allowing the execution of arbitrary code, while the third could result in denial of service. More information on this vulnerability is found in Microsoft Security Bulletin MS03-039.

  • The Windows Plug and Play vulnerability, which allows a remote user to promote his privileges and execute arbitrary codes. This vulnerability is discussed in detail in Microsoft Security Bulletin MS05-039.

Note that this propagation routine works only on Windows 2000 because the Microsoft Windows Plug and Play vulnerability has inherent characteristics that prevent this worm from exploiting it on Windows XP.

Backdoor Capabilities

Using a random port, this worm connects to an Internet Relay Chat (IRC) server and joins a specific channel, where it listens for the following commands from a remote malicious user:

  • Update the copy of this worm
  • Perform denial of services (DoS) attacks using various flooding methods
  • List and terminate processes
  • Perform basic IRC commands
  • Perform incoming and outgoing packet sniffing
  • Emmulate an FTP server on the affected system
  • List and terminate network shares
  • Enable and disable DCOM
  • Scan the system for exploits

It executes these commands locally on an affected system, providing the remote user virtual control over the machine.

Denial of Service Attack

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

  • ICMP flood
  • SYN flood

Process Termination

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

  • ANTIVIRUS.EXE
  • BAGLE.V
  • BDSS.EXE
  • BDSWITCH.EXE
  • FIREWALL.EXE
  • MICROSOFT INET XP..
  • MSBLAST.EXE
  • MSCONFIG.EXE
  • MSCVB32.EXE
  • MYDOOM.H
  • NETSKY.R
  • PANDAAVENGINE
  • PANDAAVENGINE.EXE
  • PENIS32.EXE
  • RAV.EXE
  • SCAN.EXE
  • SCVHOST.EXE
  • SOBIG.C
  • SYSINFO.EXE
  • SYSTEM MSCVB
  • TASKMON
  • TASKMON.EXE
  • TEEKIDS.EXE
  • W32.BLASTER
  • W32.BLASTER.B
  • W32.BLASTER.C
  • WINDOWS AUTO UPDATE
  • WINMUN32

Affected Platforms

This worm runs on Windows 2000 and XP.

Analysis By: Luis Antonio P. Magisa


SOLUTION


Minimum scan engine version needed: 7.000

Pattern file needed: 3.917.00

Pattern release date: Nov 9, 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:

Terminating the Malware Program

This procedure terminates the running malware process.

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 2000 and XP, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the process:
    fqwfeq.exe
  3. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. To check if the malware process has been terminated, close Task Manager, and then open it again.
  5. Close Task Manager.

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 2000
  2. HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and Server 2003

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>Run
  3. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.exe"
  4. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>RunServices
  5. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.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:
    GoOutside = "fqwfeq.exe"
  8. In the left panel, double-click the following:
    HKEY_CURRENT_USER>SOFTWARE>Microsoft>
    Windows>CurrentVersion>RunServices
  9. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.exe"

Removing Other Entries from the Registry

  1. Still in the Registry Editor, in the left panel, double-click the following:
    HKEY_CURRENT_USER>SYSTEM>CurrentControlSet>
    Control>LSA
  2. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.exe"
  3. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
    Control>LSA
  4. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.exe"
  5. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>OLE
  6. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.exe"
  7. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>OLE
  8. In the right panel, locate and delete the entry:
    GoOutside = "fqwfeq.exe"

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.

Important Windows XP Cleaning Instructions

Users running Windows 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 in 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_RBOT.CRD. To do this, Trend Micro customers must download the latest virus pattern file and scan their system. Other Internet users can use HouseCall, the Trend Micro online virus scanner.

Applying Patches

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

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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