TROJ_ZEMOT.SMW

April 24, 2015
 Analysis by: Rika Joi Gregorio
 ALIASES:

TrojanDownloader:Win32/Carberp(Microsoft),

 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

File Size:

98,111 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Jun 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 and executes the following files:

  • %Program Files%\NVIDIA Corporation\nv_update.exe

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It creates the following folders:

  • %Program Files%\NVIDIA Corporation

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Autostart Technique

This Trojan registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NvUpdSrv
ImagePath = "%Program Files%\NVIDIA Corporation\nv_update.exe /svc"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NvUpdSrv
DisplayName = "NVIDIA Update Server"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NvUpdSrv
Description = "NVIDIA Settings Update Manager service, used to check new updates from NVIDIA server"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NvUpdSrv

Other System Modifications

This Trojan adds the following registry keys:

HKEY_USERS\.DEFAULT\Software\
NVIDIA Corporation

HKEY_USERS\.DEFAULT\Software\
NVIDIA Corporation\Global

HKEY_USERS\.DEFAULT\Software\
NVIDIA Corporation\Global\nvUpdSrv

HKEY_USERS\.DEFAULT\Software\
{random value}

HKEY_USERS\.DEFAULT\Software\
{random value}\PortScan

HKEY_USERS\.DEFAULT\Software\
{random value}\PortScan\Settings

It adds the following registry entries:

HKEY_USERS\.DEFAULT\Software\
NVIDIA Corporation\Global\nvUpdSrv
value = "{random digits}"

HKEY_USERS\.DEFAULT\Software\
NVIDIA Corporation\Global\nvUpdSrv
GUID = "{random GUID}"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}79.156.4
  • {BLOCKED}.{BLOCKED}59.162.167
  • {BLOCKED}.{BLOCKED}2.255.157
  • {BLOCKED}.{BLOCKED}221.3.142
  • {BLOCKED}.{BLOCKED}34.13.203
  • {BLOCKED}.{BLOCKED}12.199.36
  • {BLOCKED}.{BLOCKED}225.208.11
  • {BLOCKED}.{BLOCKED}168.221.25
  • {BLOCKED}.{BLOCKED}58.4.190
  • {BLOCKED}.{BLOCKED}20.130.99