Author: Carl Maverick Pascual   

 

Trojan.Win32.Cosmu.dnhd (Kaspersky) ; Trojan:Win32/Dynamer!ac (Microsoft)

 PLATFORM:

Windows

 OVER ALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE
Low
Medium
High
Critical

  • Threat Type:
    Worm

  • Destructiveness:
    No

  • Encrypted:
     

  • In the wild:
    Yes

  OVERVIEW

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

It drops copies of itself into all the removable drives connected to an affected system.

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

  TECHNICAL DETAILS

File size: 1,178,304 bytes
File type: EXE
Memory resident: No
INITIAL SAMPLES RECEIVED DATE: 12 November 2018

Arrival Details

This Worm 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 Worm drops the following files:

  • %User Temp%\Tr.exe
  • %User Temp%\x.exe
  • %User Temp%\Data.txt
  • %User Startup%\Microsoft.lnk
  • {Removable Drive}:\x.exe
  • {Removable Drive}:\.lnk

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It drops the following copies of itself into the affected system:

  • %User Temp%\x.exe

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

Autostart Technique

This Worm drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\Microsoft.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Propagation

This Worm creates the following folders in all removable drives:

  • sss

It drops copies of itself into all the removable drives connected to an affected system.

It creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Dropping Routine

This Worm executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.

Other Details

This Worm does the following:

  • It moves the files from the root directory of removable drives to the created folder {removable drive}\sss

  SOLUTION

Minimum scan engine: 9.850
First VSAPI Pattern File: 14.633.00
First VSAPI Pattern Release Date: 18 November 2018
VSAPI OPR PATTERN-VERSION: 14.633.00
VSAPI OPR PATTERN DATE: 19 November 2018

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

Identify and terminate files detected as Worm.Win32.BLADABINDI.AA

[ learnMore ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Search and delete this file

[ learnMore ]
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 Temp%\Tr.exe
  • %User Temp%\x.exe
  • %User Temp%\Data.txt
  • %User Startup%\Microsoft.lnk
  • {Removable Drive}:\x.exe
  • {Removable Drive}:\.lnk

Step 5

Scan your computer with your Trend Micro product to delete files detected as Worm.Win32.BLADABINDI.AA. 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 the following Trend Micro Support pages for more information:


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