Analysis by: David John Agni
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

The malicious files <i>flash32.exe</i> and <i>kbflashUpd.dll</i> are detected as TROJ_FLASHUP.A and TROJ_FLASHUP.B, respectively. These are the downloaded payloads of TROJ_NETISON.AB. The malware TROJ_NETISON.AB is the payload from the Adobe Flash zero-day vulnerability CVE-2015-5119.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan may be downloaded from remote sites by other malware.

  TECHNICAL DETAILS

File Size: 76,288 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 08 Jul 2015

Arrival Details

This Trojan may be downloaded from remote site(s) by the following malware:

Installation

This Trojan s DLL component is injected to the following process(es):

  • dwm.exe
  • wuauclt.exe
  • ctfmon.exe
  • wscntfy.exe

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Windows Update Process
  • Windows Update System Verifier

It terminates itself if it finds the following processes in the affected system's memory:

  • Regmon.exe
  • Filemon.exe
  • Procmon.exe

Other Details

This Trojan requires the existence of the following files to properly run:

  • %System%\kbflashUpd.dll - detected as TROJ_FLASHUP.B
  • %System%\flash32.exe - detected as TROJ_FLASHUP.A

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.780.01
FIRST VSAPI PATTERN DATE: 09 Jul 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

Remove the malware/grayware file that dropped/downloaded TROJ_FLASHUP.A. (Note: Please skip this step if the threat(s) listed below have already been removed.)

Step 4

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


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