arrow_back
search
close

TROJ_ZEGOST.HT

October 13, 2012
 ALIASES:

TrojanDropper:Win32/Zegost.B (Microsoft); PAK:ZProtect, Trojan-PSW.Win32.Bjlog.aabz, Trojan-PSW.Win32.Bjlog.lby (Kaspersky); Trojan-Dropper.Win32.Resdro.b (v) (not malicious) (Sunbelt)

 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:

24,063,048 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

31 Jul 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.

Installation

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

  • %System Root%\emyfumeqnh

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %User Profile%\Application Data\Storm
  • %User Profile%\Storm\update
  • %User Profile%\update\%SESSIONNAME%

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Other System Modifications

This Trojan deletes the following files:

  • %User Profile%\%SESSIONNAME%\objjx.cc3
  • xylclyxjr
  • %System Root%\emyfumeqnh
  • ufpfgsocym

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\sOFtwaRe\xylclyxjr

HKEY_LOCAL_MACHINE\sOFtwaRe\xylclyxjrt

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Comhidserv70

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\xylclyxjr
seRVicemAIN = "BuildTrusteeWithSidA"

HKEY_LOCAL_MACHINE\SOFTWARE\xylclyxjr
seRVicedlL = "%User Profile%\%SESSIONNAME%\objjx.cc3"

HKEY_LOCAL_MACHINE\SOFTWARE\xylclyxjr
module = "%System Root%\emyfumeqnh"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\uqfbnnvmwe.dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

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

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
    • xylclyxjr
  • In HKEY_LOCAL_MACHINE\sOFtwaRe
    • xylclyxjrt
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • Comhidserv70
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo

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\xylclyxjr
    • seRVicemAIN = "BuildTrusteeWithSidA"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\xylclyxjr
    • seRVicedlL = "%User Profile%\%SESSIONNAME%\objjx.cc3"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\xylclyxjr
    • module = "%System Root%\emyfumeqnh"

Step 4

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.
  • %User Temp%\uqfbnnvmwe.dat

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\Application Data\Storm
  • %User Profile%\Storm\update
  • %User Profile%\update\%SESSIONNAME%

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_ZEGOST.HT. 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.

  • %User Profile%\%SESSIONNAME%\objjx.cc3
  • xylclyxjr
  • %System Root%\emyfumeqnh
  • ufpfgsocym


Did this description help? Tell us how we did.