TSPY_EMOTET.THAOIAN

 Analysis by: Nikko Tamana

 PLATFORM:

Windows

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

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be downloaded by other malware/grayware/spyware from remote sites.

  TECHNICAL DETAILS

File Size:

135,168 bytes

Initial Samples Received Date:

17 Jan 2018

Arrival Details

This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It may be downloaded by other malware/grayware/spyware from remote sites.

Installation

This Trojan Spy drops the following copies of itself into the affected system and executes them:

  • %AppDataLocal%\Microsoft\Windows\{string 1}{string 2}.exe - drops the file here if it has no admin privileges
  • %System%\{string 1}{string 2}.exe - drops the file here if it has admin privileges
    where {string 1} and {string 2} is a combination of any of the following strings:
    • agent
    • app
    • audio
    • bio
    • bits
    • cache
    • card
    • cart
    • cert
    • com
    • crypt
    • dcom
    • defrag
    • device
    • dhcp
    • dns
    • event
    • evt
    • flt
    • gdi
    • group
    • help
    • home
    • host
    • info
    • iso
    • launch
    • log
    • logon
    • lookup
    • man
    • math
    • mgmt
    • msi
    • ncb
    • net
    • nv
    • nvidia
    • proc
    • prop
    • prov
    • provider
    • reg
    • rpc
    • screen
    • search
    • sec
    • server
    • service
    • shed
    • shedule
    • spec
    • srv
    • storage
    • svc
    • sys
    • system
    • task
    • time
    • video
    • view
    • win
    • window
    • wlan
    • wmi

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

Autostart Technique

This Trojan Spy 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\
services\{string 1}{string 2}
ImagePath = "%System%\{string 1}{string 2}.exe" if it has admin privileges
where {string 1} and {string 2} is the same name as the drop file

It adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{string 1}{string 2} = "%AppDataLocal%\Microsoft\Windows\{string 1}{string 2}.exe" if it has no admin privileges

Other Details

This Trojan Spy connects to the following possibly malicious URL:

  • http://198.61.2{BLOCKED}74:443/