TSPY_URSNIF.YYSWR

 Analysis by: Byron Jon Gelera

 ALIASES:

TrojanSpy:Win32/Ursnif.HN (Microsoft); Win32/PSW.Papras.EH (ESET-NOD32)

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

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

322,560 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

27 Sep 2016

Arrival Details

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

  • %Application Data%\{string1}{string2}\{string1}{string2}.exe
    where:
    {string1} = first four letters of a dll file under %System% directory
    {string2} = last four letters of a dll file under %System% directory

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

It drops the following component file(s):

  • %User Temp%\{random filename}.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.)

It drops and executes the following files:

  • %User Temp%\{random folder name}\{random filename}.bat ← use to delete itself; deleted afterwards

(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 creates the following folders:

  • %Application Data%\{string1}{string2}
    where:
    {string1} = first four letters of a dll file under %System% directory
    {string2} = last four letters of a dll file under %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
{string1}{string2} = "%Application Data%\{string1}{string2}\{string1}{string2}.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Vars

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Files

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Run

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Config

It adds the following registry entries:

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}
{Value Name} = "{hex value}"
where {Value Name} may any of the following:

  • Block
  • Client
  • Install
  • LastTask
  • CrHook
  • OpHook

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}
{UID} = "{hex value}"

Other Details

This spyware connects to the following possibly malicious URL:

  • http://{domain}/{r/g/q}{random}.php?{random}={b64 encoded data}
    where {domain} can be any of the following:
    • {BLOCKED}s.{BLOCKED}e.com
    • {BLOCKED}owerltd.in
    • {BLOCKED}man9.in

    It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.804.05

FIRST VSAPI PATTERN DATE:

28 Sep 2016

VSAPI OPR PATTERN File:

12.805.00

VSAPI OPR PATTERN Date:

29 Sep 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 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
    • {string1}{string2} = "%Application Data%\{string1}{string2}\{string1}{string2}.exe"

Step 5

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_CURRENT_USER\Software\AppDataLow\Software\Microsoft
    • {GUID}

Step 6

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 folder name}\{random filename}.bat
  • %User Temp%\{random filename}.bin

Step 7

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