Analysis by: Pearl Charlaine Espejo

ALIASES:

TrojanSpy:Win32/Ursnif (Microsoft); Win32/PSW.Papras.DS (ESET-NOD32); W32/Backdoor2.HYRW (F-Prot); W32/Papras.DS!tr.pws (Fortinet); RDN/Generic PWS.y!bdp (McAfee)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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 itself after execution.

  TECHNICAL DETAILS

File Size: 434,176 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 15 Jun 2015
Payload: Steals information, Connects to URLs/IPs

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:

  • %User Temp%\{string1 + string2}.exe (for Windows Vista and above)

    where:
    • {string1} = first four letters of a dll file under %System% directory
    • {string2} = last four letters of a dll file under %System% directory
      (e.g. ciadt500.exe = ciadmin.dll + jet500.dll)


  • %System%\{string1 + string2}.exe (for Windows XP and below)

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

It drops and executes the following files:

  • %User Temp%\{Random Filename}.bat - batch file to delete the executed copy

(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.)

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} = "%User Temp%\{string1 + string2}.exe" (for Windows Vista and above)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "%System%\{string1 + string2}.exe" (for Windows XP and below)

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\AppDataLow\
{GUID}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\AppDataLow\
{GUID}
Install = "{hex value}"

HKEY_CURRENT_USER\Software\AppDataLow\
{GUID}
Client = "{hex value}"

Other Details

This spyware connects to the following possibly malicious URL:

  • http://{BLOCKED}ecarsdaysforum.xyz/geodata/version/ip2ext
  • http://{BLOCKED}steelsforums.xyz/geodata/version/ip2ext
  • http://{BLOCKED}ersbrenderns.com/geodata/version/ip2ext
  • http://{BLOCKED}systemsbreds.com/geodata/version/ip2ext

It deletes itself after execution.

NOTES:

It locates the following registries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Paths
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths

If found, it adds the following registry value to exclude its dropped copy everytime an antivirus software performs a scan:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Paths
    • %System%\{string1 + string2}.exe = 0 (for Windows XP and below)
    • %User Temp%\{string1 + string2}.exe = 0 (for Windows Vista and above)
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Paths
    • %System%\{string1 + string2}.exe = 0 (for Windows XP and below)
    • %User Temp%\{string1 + string2}.exe = 0 (for Windows Vista and above)

It deletes the Zone.Identifier NTFS stream to remove the downloaded files history.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.732.06
FIRST VSAPI PATTERN DATE: 15 Jun 2015
VSAPI OPR PATTERN File: 11.733.00
VSAPI OPR PATTERN Date: 16 Jun 2015

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_CURRENT_USER\Software\AppDataLow
    • {GUID}

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
    • {random} = "{%User Temp% or %System%}\{string1 + string2}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Paths
    • %System%\{string1 + string2}.exe = "0"   (for Windows XP and below)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Paths
    • %User Temp%\{string1 + string2}.exe = "0"   (for Windows Vista and above)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %System%\{string1 + string2}.exe = "0"   (for Windows XP and below)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %User Temp%\{string1 + string2}.exe = "0"   (for Windows Vista and above)

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 Filename}.bat

Step 7

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