ALIASES:

Trojan:Win32/Beaugrit.gen!AAA (Microsoft); Trojan.Win32.Staser.wux (Kaspersky); Trojan.Win32.Zegost.lt (v) (Sunbelt); Trojan horse BackDoor.Generic_r.GAD (AVG)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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: 336,322 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 May 2014

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%\Uiytsq.exe

(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:

  • %Program Files%\Windows Qumhbs

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

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\Wsvimo isiyylef

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Cwldqe dsyxsw

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Wsvimo isiyylef
ReleiceName = "Uiytsq.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Wsvimo isiyylef
ReleiceName = "Cwldqe dsyxsw"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Cwldqe dsyxsw
ConnectGroup = "ĬÈÏ·Ö×é"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Cwldqe dsyxsw
MarkTime = "2014-05-07 04:25"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Cwldqe dsyxsw
Description = "Jquwyj qrymoroi rqoggeypkug"

Dropping Routine

This Trojan drops the following files:

  • %System Root%\4985.vbs
  • %System Root%\7244.vbs
  • %Program Files%\Windows Qumhbs\server.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.239.236

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.700

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

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
    • Wsvimo isiyylef
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • Cwldqe dsyxsw

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\SYSTEM\ControlSet001\Services\Wsvimo isiyylef
    • ReleiceName = "Uiytsq.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Wsvimo isiyylef
    • ReleiceName = "Cwldqe dsyxsw"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Cwldqe dsyxsw
    • ConnectGroup = "ĬÈÏ·Ö×é"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Cwldqe dsyxsw
    • MarkTime = "2014-05-07 04:25"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Cwldqe dsyxsw
    • Description = "Jquwyj qrymoroi rqoggeypkug"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %System Root%\4985.vbs
  • %System Root%\7244.vbs
  • %Program Files%\Windows Qumhbs\server.exe

Step 6

Search and delete this folder

[ 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.
  • %Program Files%\Windows Qumhbs

Step 7

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