Analysis by: Denisse Camille Layco

ALIASES:

TrojanDownloader:O97M/Emotet.CSK!MTB (MICROSOFT); W97M/Downloader.dif (NAI)

 PLATFORM:

Windows

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

  • 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.

  TECHNICAL DETAILS

Tamaño del archivo 218,460 bytes
Tipo de archivo DOC
Fecha de recepción de las muestras iniciales 23 Dec 2020

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:

  • %User Profile%\O_wgqv7\C0316em\Lyeta6ud.dll -> deleted later
  • When ran with administrator privileges:
    • %System%\{random characters}\{random characters}.{random characters}
  • When ran without administrator privileges:
    • %AppDataLocal%\{random characters}\{random characters}.{random characters}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %System%\wbem\wmiprvse.exe -secured -Embedding
  • cmd cmd cmd cmd /c msg %username% /v Word experienced an error trying to open the file. & POwersheLL -w hidden -ENCOD {Base64 encoded string}
  • "%System%\rundll32.exe" %User Profile%\O_wgqv7\C0316em\Lyeta6ud.dll #1
  • When ran with administrator privileges:
    • %System%\rundll32.exe "%System%\{random characters}\{random characters}.{random characters}",RunDLL
  • When ran without administrator privileges:
    • %System%\rundll32.exe "%AppDataLocal%\{random characters}\{random characters}.{random characters}",RunDLL

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It creates the following folders:

  • %User Profile%\O_wgqv7
  • %User Profile%\O_wgqv7\C0316em
  • When ran with administrator privileges:
    • %System%\{random characters}
  • When ran without administrator privileges:
    • %AppDataLocal%\{random characters}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}campus.com/l/yQ/
  • http://apps.{BLOCKED}ust.com/roots/dstrootcax3.p7c
  • http://{BLOCKED}rdableroofer.com/ralphs-receipt-f2uhf/qTT5DC/
  • http://{BLOCKED}ileged.com/cgi-bin/kcggF/
  • http://{BLOCKED}.{BLOCKED}.209.15/{random characters}/
  • http://{BLOCKED}.{BLOCKED}.237.56:8080/{random characters}
  • http://{BLOCKED}.{BLOCKED}.148.58:443/{random characters}