Analysis by: Mar Philip Elaurza
ALIASES:

Win32/Rozena.KA (ESET-NOD32), Trojan.Win32.Small.dmelfl (NANO-Antivirus)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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. It arrives as a component bundled with malware/grayware packages.

It modifies the Internet Explorer Zone Settings.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 8,193 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 12 Nov 2015
Payload: Downloads files

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.

It arrives as a component bundled with malware/grayware packages.

Installation

This Trojan drops the following file(s)/component(s):

  • {malware path}\dlls.dll
  • {malware path}\dll.dll
  • {malware path}\sv.exe

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Dropping Routine

This Trojan executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}.{BLOCKED}.48.90:443

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 11.486.05
FIRST VSAPI PATTERN DATE: 18 Feb 2015
VSAPI OPR PATTERN File: 11.487.00
VSAPI OPR PATTERN Date: 19 Feb 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Search and delete these files

[ 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.  
  • {malware path}\dlls.dll
  • {malware path}\dll.dll
  • {malware path}\sv.exe

Step 4

Reset Internet security settings

[ Learn More ]

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_ROZENA.GJS. 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.


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