Analysis by: Carlos Villegas Madrid
ALIASES:

Dropper.MSIL.gen (VBA32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size: 3,706,880 bytes
File Type: EXE
Memory Resident: No
Payload: Drops files

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 files:

  • %System%\psgfilter.dll
  • %ProgramData%\WindowsSoftwareDevices\DevicesSrv.exe → detected as Backdoor.MSIL.SAITAMA.AA
  • %ProgramData%\WindowsSoftwareDevices\Microsoft.Exchange.WebServices.dll
  • %ProgramData%\WindowsSoftwareDevices\DevicesSrv.exe.config

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Lsa
Notification Packages = scecli, psgfilter

Information Theft

This Trojan accepts the following parameters:

  • -i → to install
  • -u → to uninstall

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.148.02
FIRST VSAPI PATTERN DATE: 22 Dec 2022
VSAPI OPR PATTERN File: 18.149.00
VSAPI OPR PATTERN Date: 23 Dec 2022

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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\SYSTEM\ControlSet001\Control\Lsa
    • Notification Packages = scecli, psgfilter

Step 4

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%\psgfilter.dll
  • %ProgramData%\WindowsSoftwareDevices\DevicesSrv.exe
  • %ProgramData%\WindowsSoftwareDevices\Microsoft.Exchange.WebServices.dll
  • %ProgramData%\WindowsSoftwareDevices\DevicesSrv.exe.config

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.MSIL.SAITAMA.AA. 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 the following Trend Micro Support pages for more information:


Did this description help? Tell us how we did.