WORM_RBOT.AUS

Malware type: Worm

Aliases: Backdoor.Win32.Rbot.bzf (Kaspersky), W32/Sdbot.worm (McAfee), W32.IRCBot (Symantec), Worm/IrcBot.79 (Avira),

In the wild: Yes

Language: English

Platform: Windows 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

This worm propagates via network shares. It uses NetBEUI functions to get available lists of user names and passwords from an affected sytem. It then lists down available network shares and uses the gathered user names and passwords to access and drop copies of itself into the network shares.

It also generates IP addresses and attempts to drop copies of itself into certain default shares of target addresses. It likewise uses the gathered user names and passwords to access these shares. It also uses a list of strings as user names and passwords apart from those that it gathers.

This worm also exploits the following Windows vulnerabilities to propagate across networks:

  • IIS5/WebDAV vulnerability
  • Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability
  • LSASS vulnerability

More information on these vulnerabilities can be found on the following Web pages:

This worm has backdoor capabilities. It connects to a remote IRC server and joins a specific IRC channel, where it listens for commands coming from a remote malicious user. It executes these commands locally on an affected system, providing the remote user virtual control over the system.

It allows remote malicious users to launch denial of service attacks against a target site.

For additional information about this threat, see:

Description created: Mar. 16, 2005 2:21:51 AM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 99,328 bytes

Initial samples received on: Mar 15, 2005

Compression type: Morphine

Vulnerability used:  (MS04-011) Security Update for Microsoft Windows (835732), (MS03-007) Unchecked Buffer In Windows Component Could Cause Server Compromise (815021), (MS03-026) Buffer Overrun In RPC Interface Could Allow Code Execution

Payload 1: Compromises system security

Payload 2: Launches DoS attacks

Details:

Arrival and Installation

This memory-resident worm may arrive from network shares. Upon execution, it drops a copy of itself in the Windows system folder as VGACARD6.EXE.

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

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run
VGA6 Startup = "vgacard6.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\Run
VGA6 Startup = "vgacard6.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\RunServices
VGA6 Startup = "vgacard6.exe"

It also modifies the following registry entries:

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

(Note: The default value of this registry entry is "Y".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Lsa restrictanonymous = "dword:00000001"

(Note: The default value of this registry entry is "dword:00000000".)

Network Propagation and Exploits

This worm propagates via network shares. It uses NetBEUI functions to get available lists of user names and passwords from an affected sytem. It then lists down available network shares and uses the gathered user names and passwords to access and drop copies of itself into the network shares.

It also generates IP addresses and attempts to drop copies of itself into the following default shares of target addresses:

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

It likewise uses the gathered user names and passwords to access these shares. It also uses the following list of strings as user names and passwords apart from those that it gathers:

  • 12345
  • 123456
  • 1234567
  • 12345678
  • 123456789
  • 1234567890
  • access
  • accounting
  • accounts
  • admin
  • administrador
  • administrat
  • administrateur
  • administrator
  • admins
  • backup
  • bitch
  • blank
  • brian
  • changeme
  • chris
  • cisco
  • compaq
  • computer
  • control
  • database
  • databasepass
  • databasepassword
  • db1234
  • dbpass
  • dbpassword
  • default
  • domain
  • domainpass
  • domainpassword
  • exchange
  • george
  • guest
  • hello
  • homeuser
  • internet
  • intranet
  • katie
  • linux
  • login
  • loginpass
  • nokia
  • oeminstall
  • oemuser
  • office
  • oracle
  • orainstall
  • outlook
  • owner
  • pass1234
  • passwd
  • password
  • password1
  • peter
  • qwerty
  • server
  • siemens
  • sqlpassoainstall
  • staff
  • staff
  • student
  • susan
  • system
  • teacher
  • technical
  • win2000
  • win2k
  • win98
  • windows
  • winnt
  • winpass
  • winxp
  • wwwadmin

It remotely executes every successfully dropped copy of itself as a service.

This worm also exploits the following Windows vulnerabilities to propagate across networks:

  • IIS5/WebDAV vulnerability
  • Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability
  • LSASS vulnerability

More information on these vulnerabilities can be found on the following Web pages:

Backdoor Capabilities

This worm has backdoor capabilities. It connects to a remote IRC server and joins a specific IRC channel, where it listens for commands coming from a remote malicious user, such as the following:

  • Change IRC server and channel it connects to
  • Download and execute files
  • Flush DNS cache
  • Add or remove default network shares
  • Enable DCOM protocol
  • Get system information, such as CPU speed, free memory, uptime, and free disk space
  • Add or remove services
  • Add, remove, or view registry entries
  • Delete files
  • Emulate an FTP server
  • List and terminate services and processes
  • Scan local area network for listening ports
  • Emulate a proxy server
  • Redirect connections
  • Log keystrokes

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

Denial of Service Attack

This worm allows remote malicious users to launch the following forms of denial of service attack:

  • HTTP flood
  • Ping flood
  • SYN flood
  • UPD flood

Other Details

This worm runs on Windows 2000 and XP.

Analysis By: Raymond Richard Bautista Gamboa

Revision History:

First pattern file version: 2.499.02
First pattern file release date: Mar 16, 2005

SOLUTION


Minimum scan engine version needed: 6.810

Pattern file needed: 3.833.00

Pattern release date: Oct 11, 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 all files detected as WORM_RBOT.AUS.

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. 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.

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:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    VGA6 Startup = "vgacard6.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:
    VGA6 Startup = "vgacard6.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:
    VGA6 Startup = "vgacard6.exe"

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

Restoring Registry Modifications

  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"
    and change this to its default value:
    EnableDCOM = "Y"
  3. Close Registry Editor.

Restoring EnableDCOM and Restrict Anonymous Registry Entries

This malware modifies EnableDCOM and Restrict Anonymous 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 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

Scan your system with Trend Micro antivirus and delete all files detected as WORM_RBOT.AUS. 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 Windows. Download and install the fix patches from the following Microsoft Web pages:

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




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