BKDR_DASERF.NZV

 Analysis by: Rheniel Rhay Ramos

 ALIASES:

Trojan.Win32.Inject.aarom (Kaspersky); Suspicious.Cloud.2 (Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet


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 executes then deletes itself afterward.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

503,808 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

06 Aug 2016

Payload:

Connects to URLs/IPs, Downloads files, Terminates processes, Steals information

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 and executes the following files:

  • %User Temp%\{temp filename}.bat -> used to delete the malware and itself

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It executes then deletes itself afterward.

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

  • Global\24203

Autostart Technique

This Backdoor starts the following services:

  • ServiceName = "swprv3"
    DisplayName = "Microsoft Software Shadow Copy Provider System Information"
    BinaryPathName = """C:\Program Files\internet explorer\pd7.exe"""

Other System Modifications

This Backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
Type = 272

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
ErrorControl = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
ImagePath = "%Program Files%\internet explorer\pd7.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
DisplayName = "Microsoft Software Shadow Copy Provider System Information"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv3
Description = "???Manages software-based volume shadow copies taken by the Volume Shadow Copy service. If this service is stopped, software-based volume shadow copies cannot be managed. If this service is disabled, any services that explicitly depend on it will fail to start."

Propagation

This Backdoor does not have any propagation routine.

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Execute Powershell commands
  • Uninstall itself
  • Install PlugIn
  • Change Activity Time
  • Change download URL
  • Sleep
  • Gather System Information
  • Perform Remote Shell
  • Create or terminate processes
  • Upload, Download, or Execute Files
  • Enumerate all drives with corresponding drive types
  • Get sha1/md5 of file
  • Search, Move, or Delete files
  • Get File Information
  • Create, Change, or Delete Directory
  • Enumerate files and directories

It connects to the following websites to send and receive information:

  • http://{BLOCKED}.{BLOCKED}.204.100/0002/phptunnel.php?t0=00000956&t1=0&t2=c45d5aca&t3=0&t6=1000

Dropping Routine

This Backdoor drops the following files:

  • %Program Files%\internet explorer\pd7.exe

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Information Theft

This Backdoor gathers the following data:

  • Computer Name
  • System Default Language ID
  • OS Version
  • Is administrator
  • Is 64-bit
  • Available Disk Space
  • User Name

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.722.01

FIRST VSAPI PATTERN DATE:

15 Oct 2017

VSAPI OPR PATTERN File:

13.723.00

VSAPI OPR PATTERN Date:

16 Oct 2017

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

Restart in Safe Mode, and then 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\SYSTEM\CurrentControlSet\Services
    • swprv3

Step 4

Disable this malware service

[ Learn More ]
    • swprv3

Step 5

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 Temp%\{temp filename}.bat
  • %Program Files%\internet explorer\pd7.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_DASERF.NZV. 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 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_DASERF.NZV. 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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