WORM_TATERF.QWZD

 Analysis by: Pearl Charlaine Espejo

 ALIASES:

Worm:Win32/Taterf.B (Microsoft); WORM/Taterf.B.205 (Avira)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives via removable drives. It 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 an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

However, as of this writing, the said sites are inaccessible. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

113,383 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Jan 2016

Arrival Details

This worm arrives via removable drives.

It 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 copies of itself into the affected system:

  • %System%\j3ewro.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following files:

  • %System%\drivers\klif.sys
  • %System%\jwedsfdo{number}.dll

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
jvsoft = "%System%\j3ewro.exe"

It creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KAVsys
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KAVsys
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KAVsys
ImagePath = "%System%\drivers\klif.sys"

Other System Modifications

This worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDriveTypeAutoRun = "145"

(Note: The default value data of the said registry entry is 255.)

Propagation

This worm drops the following copy of itself in all physical and removable drives:

  • {drive letter}:\ejoq.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

;{garbage}
[AutoRun]
;{garbage}
open=ejoq.exe
;{garbage}
shell\open\Command=ejoq.exe
;{garbage}
shell\open\Default=1
;{garbage}
shell\Explore\command=ejoq.exe
;{garbage}

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}o.com/xjj/cc1.rar

However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.284.03

FIRST VSAPI PATTERN DATE:

20 Jan 2016

VSAPI OPR PATTERN File:

12.285.80

VSAPI OPR PATTERN Date:

21 Jan 2016

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

[ Learn More ]

Step 4

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
    • KAVsys

Step 5

Delete this registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • jvsoft = "%System%\j3ewro.exe"

Step 6

Restore this modified registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoDriveTypeAutoRun = "145"
      To: NoDriveTypeAutoRun = "255"

Step 7

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.  
  • %System%\drivers\klif.sys
  • %System%\jwedsfdo{number}.dll

Step 8

Search and delete AUTORUN.INF files created by WORM_TATERF.QWZD that contain these strings

[ Learn More ]
;{garbage}

[AutoRun]

;{garbage}

open=ejoq.exe

;{garbage}

shell\open\Command=ejoq.exe

;{garbage}

shell\open\Default=1

;{garbage}

shell\Explore\command=ejoq.exe

;{garbage}

Step 9

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