ALIASES:

Backdoor:Win32/Rbot.gen (Microsoft); W32/Sdbot.worm.gen.bi (McAfee); W32.Spybot.Worm (Symantec); Backdoor.Win32.DsBot.jm (Kaspersky); Backdoor.Win32.DsBot.bp (v) (Sunbelt); Trojan horse IRC/BackDoor.SdBot2.BMJ (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 59,904 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 22 May 2013

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This worm drops the following copies of itself into the affected system:

  • %Windows%\regsvr32.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\WindowsFirewall\DomainProfile

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\WindowsFirewall\StandardProfile

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Shell Extensions
Melt = "{malware path and file name}"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\WindowsFirewall\DomainProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\WindowsFirewall\StandardProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\WindowsUpdate\
Auto Update
AUOptions = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\lanmanserver\parameters
AutoShareWks = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\lanmanserver\parameters
AutoShareServer = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\lanmanworkstation\parameters
AutoShareWks = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\lanmanworkstation\parameters
AutoShareServer = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate
DoNotAllowXPSP2 = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control
WaitToKillServiceTimeout = "7000"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wscsvc
Start = "4"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\TlntSvr
Start = "4"

(Note: The default value data of the said registry entry is 4.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\RemoteRegistry
Start = "4"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Messenger
Start = "4"

(Note: The default value data of the said registry entry is 4.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Lsa
restrictanonymous = "1"

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

(Note: The default value data of the said registry entry is Y.)

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}e.com

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall
    • DomainProfile
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall
    • StandardProfile

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions
    • Melt = "{malware path and file name}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile
    • EnableFirewall = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile
    • EnableFirewall = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update
    • AUOptions = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\lanmanserver\parameters
    • AutoShareWks = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\lanmanserver\parameters
    • AutoShareServer = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\lanmanworkstation\parameters
    • AutoShareWks = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\lanmanworkstation\parameters
    • AutoShareServer = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
    • DoNotAllowXPSP2 = "1"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control
    • From: WaitToKillServiceTimeout = "7000"
      To: WaitToKillServiceTimeout = ""20000""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UpdatesDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • AntiVirusDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • FirewallDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • AntiVirusOverride = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • FirewallOverride = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wscsvc
    • From: Start = "4"
      To: Start = ""2""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\TlntSvr
    • From: Start = "4"
      To: Start = ""4""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\RemoteRegistry
    • From: Start = "4"
      To: Start = ""2""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Messenger
    • From: Start = "4"
      To: Start = ""4""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Lsa
    • restrictanonymous = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole
    • From: EnableDCOM = "N"
      To: EnableDCOM = ""Y""

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_SDBOT.AZX. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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