arrow_back
search
close

BKDR_ZYKLON.A

March 01, 2017
 ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft); Fareit-FHE!32B3F3BF3EC6 (McAfee); Trojan.Gen.2 (Symantec); Trojan.Win32.VBKryjetor.afsd (Kaspersky); Troj/Agent-AUUE (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Atros4.BPRM (AVG)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

5,148,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Mar 2017

Arrival Details

This backdoor 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 backdoor drops the following copies of itself into the affected system:

  • %User Profile%\Application Data\itunes.exe

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
itunes = "%User Profile%\Application Data\itunes.exe "

Other System Modifications

This backdoor deletes the following files:

  • {malware path and file name}:zone.identifier

Dropping Routine

This backdoor drops the following files:

  • %User Startup%\itunes.vbs

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}139.102
  • {BLOCKED}0.1

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.8

Step 1

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

Step 2

Restart in Safe Mode

[ Learn More ]

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • itunes = "%User Profile%\Application Data\itunes.exe "

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.
  • %User Startup%\itunes.vbs

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZYKLON.A. 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 this Knowledge Base page for more information.

Step 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • {malware path and file name}:zone.identifier


Did this description help? Tell us how we did.