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DDOS_AGENT.III

October 13, 2012
 ALIASES:

Backdoor:Win32/Zegost.G (Microsoft); Generic BackDoor!1ql (McAfee); Infostealer.Gampass (Symantec); Trojan.Win32.Redosdru.aji (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.6928769 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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:

135,338 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Jun 2012

Arrival Details

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

Autostart Technique

This Trojan registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wind0ws\Parameters

Other System Modifications

This Trojan deletes the following files:

  • %Windows%\ThankU.txt

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

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\ThankU

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\ThankU
netsvcs = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wind0ws
Description = "Microsoft(R) Windows Update"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wind0ws\Parameters
ServiceDll = "%Program Files%\Windows Media Player\COMMTB32.dll"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wind0ws
InstallModule = "{malware path and file name}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wind0ws
ConnectGroup = "СÄϼ¼ÊõС×é"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wind0ws
Type = "12"

Dropping Routine

This Trojan drops the following files:

  • %Program Files%\Windows Media Player\COMMTB32.dll

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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\SYSTEM\CurrentControlSet\Services\wind0ws
    • Parameters
  • In HKEY_LOCAL_MACHINE\Software
    • ThankU

Step 4

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\ThankU
    • netsvcs = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wind0ws
    • Description = "Microsoft(R) Windows Update"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wind0ws\Parameters
    • ServiceDll = "%Program Files%\Windows Media Player\COMMTB32.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wind0ws
    • InstallModule = "{malware path and file name}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wind0ws
    • ConnectGroup = "СÄϼ¼ÊõС×é"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wind0ws
    • Type = "12"

Step 5

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %Program Files%\Windows Media Player\COMMTB32.dll

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as DDOS_AGENT.III. 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.

Step 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Windows%\ThankU.txt


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