BKDR_ZEGOST_0000013.TOMA
Backdoor:Win32/Zegost.B (Microsoft); Generic BackDoor!1fc (McAfee); Trojan.ADH (Symantec); Trojan.Win32.Jorik.Zegost.bjy (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.6716887 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor 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
340,099 bytes
EXE
No
13 Jul 2012
Arrival Details
This backdoor 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 backdoor creates the following folders:
- %System Root%\Documents and Settings\Common
- %System Root%\Documents and Settings\LocalServer
- %Start Menu%\Programs\XXX
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.)
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo
Dropping Routine
This backdoor drops the following files:
- %User Profile%\Utility.dll
- %User Profile%\boot.bat
- %Start Menu%\Programs\XXX\calc.lnk
- %Windows%\hello.bat
- %System Root%\Documents and Settings\maomao.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.. %Windows% is the Windows folder, which is usually C:\Windows.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Other Details
This backdoor deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
9.200
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
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\Control\MediaResources
- msvideo
Step 3
Search and delete these components
- %User Profile%\Utility.dll
- %User Profile%\boot.bat
- %Start Menu%\Programs\XXX\calc.lnk
- %Windows%\hello.bat
- %System Root%\Documents and Settings\maomao.exe
Step 4
Search and delete these folders
- %System Root%\Documents and Settings\Common
- %System Root%\Documents and Settings\LocalServer
- %Start Menu%\Programs\XXX
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_ZEGOST_0000013.TOMA. 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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