TROJ_STASER.BV

 Analysis by: Sabrina Lei Sioting

 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:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


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 connects to a website to send and receive information.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

106,496 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Apr 2014

Payload:

Downloads files, Collects system information

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 non-malicious files:

  • %System%\upset1.set

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It drops the following copies of itself into the affected system:

  • %System%\Android.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It creates the following folders:

  • %System Root%\Android

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

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ANDROID\
0000
Service = "Android"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Android
ImagePath = "%System%\Android.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Android
DisplayName = "Android"

It 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\
Enum\Root\LEGACY_ANDROID

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Android

Backdoor Routine

This Trojan connects to the following websites to send and receive information:

  • {BLOCKED}.xicp.net

Download Routine

This Trojan saves the files it downloads using the following names:

  • Sudp.exe

Information Theft

This Trojan retrieves the following information from the affected system:

  • Username
  • Processor
  • OS version
  • Computer Name

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.744.05

FIRST VSAPI PATTERN DATE:

23 Apr 2014

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

Identify and terminate files detected as TROJ_STASER.BV

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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\Enum\Root
    • LEGACY_ANDROID
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • Android

Step 4

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. %System Root%\Android

Step 5

Search and delete this file

[ Learn More ]
There may be some 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. %System%\upset1.set

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_STASER.BV. 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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