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BKDR_SMALLDOO.CSA

May 17, 2018
 Analysis by: Wilbert Vidal
 ALIASES:

Bkdr.Smalldoo.Gen!c (AegisLab);

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size:

890,152 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 May 2018

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.

Other System Modifications

This Backdoor adds the following registry keys:

HKLM\SOFTWARE\Classes\
CLSID\{E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}\LocalServer32
{default} = {malware path}\{malware filename}.exe

HKLM\SOFTWARE\Classes\
CLSID\{E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}\ProgID
{default} = {malware filename}.MyNSHandler

HKLM\SOFTWARE\Classes\
CLSID\{E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}
{default} = this is my ebook

HKLM\SOFTWARE\Classes\
{malware filename}.MyNSHandler
{default} = this is my ebook

HKLM\SOFTWARE\Classes\
{malware filename}.MyNSHandler\Clsid
{default} = {E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.254.08

FIRST VSAPI PATTERN DATE:

16 May 2018

VSAPI OPR PATTERN File:

14.255.00

VSAPI OPR PATTERN Date:

17 May 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

Delete this registry key

[ 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_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}
    • {default} = this is my ebook
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}\LocalServer32
    • {default} = {malware path}\{malware filename}.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\{malware filename}.MyNSHandler
    • {default} = this is my ebook
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\{malware filename}.MyNSHandler\Clsid
    • {default} = {E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{E8CFC029-8420-4EAE-ADEF-915BDC77E1DC}\ProgID
    • {default} = {malware filename}.MyNSHandler

Step 4

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