Analysis by: RonJay Kristoffer Caragay
ALIASES:

TrojanSpy:Win32/Ursnif (Microsoft); Trojan.Win32.Bublik.duyv (Kaspersky); W32/Bublik.DUYV!tr (Fortinet); Trojan.Bublik (VBA)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This spyware arrives as attachment to mass-mailed email messages.

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

  TECHNICAL DETAILS

File Size: 284,278 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Aug 2015

Arrival Details

This spyware arrives as attachment to mass-mailed email messages.

Installation

This spyware drops the following copies of itself into the affected system:

  • %Application Data%\{random string}\{random string}.exe
    where {random string} are made up of files found in %System% directory

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "%Application Data%\{random string}\{random string}.exe"

Other System Modifications

This spyware adds the following registry entries:

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}
Install = "{hex vaue}"

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}
Client = "{hex vaue}"

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}
{GUID} = "{hex vaue}"

Dropping Routine

This spyware drops the following files:

  • %User Temp%\{random}.bin

(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.)

Other Details

This spyware connects to the following possibly malicious URL:

  • https://{BLOCKED}efa.com/images/

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

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.750

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 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
    • {random} = "%Application Data%\{random string}\{random string}.exe"

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%\{random}.bin

Step 6

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

The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

  • HKEY_CURRENT_USER\Software\AppDataLow\Software\Microsoft
    • {GUID}
  • HKEY_CURRENT_USER\Software\AppDataLow\Software\Microsoft\{GUID}
    • Install = "{hex vaue}"
  • HKEY_CURRENT_USER\Software\AppDataLow\Software\Microsoft\{GUID}
    • Client = "{hex vaue}"
  • HKEY_CURRENT_USER\Software\AppDataLow\Software\Microsoft\{GUID}
    • {GUID} = "{hex vaue}"


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