Analysis by: Kiyoshi Obuchi
ALIASES:

a variant of Win32/Kryptik.DOCP (ESET-NOD32); Trojan:Win32/Dynamer!ac (Microsoft)

 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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 266,752 bytes
File Type: EXE
Initial Samples Received Date: 12 Aug 2015

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.

Installation

This Trojan Spy adds the following folders:

  • %Application Data%\{Random characters 1}
  • %Application Data%\{Random characters 3}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

It drops the following copies of itself into the affected system and executes them:

  • %Application Data%\{Random characters 1}\{Random Characters 2}.exe and executes

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

It drops the following files:

  • %Application Data%\{Random characters 3}\{Random Characters 4}.{Random characters 5}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

Autostart Technique

This Trojan Spy modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "%Application Data%\{Random characters 1}\{Random Characters 2}.exe"

Other System Modifications

This Trojan Spy adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{Random Characters 6}
{Random Characters 7} = {Hex values}

Other Details

This Trojan Spy connects to the following possibly malicious URL:

  • http://{BLOCKED}w.su/500.jpg

However, as of this writing, the said sites are inaccessible.