Analysis by: Christopher Daniel So
ALIASES:

TrojanSpy:Win32/Ursnif.gen!K (Microsoft)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • 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 the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Mar 2014
Payload: Connects to URLs/IPs, Steals information

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:

  • %All Users Profile%\Application Data\{random file name}.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It drops the following component file(s):

  • %System%\{random file name 2}.dll - also detected by Trend Micro as TSPY_URSNIF.YNJ

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

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 file name} = "%All Users Profile%\Application Data\{random file name}.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\Microshit

It adds the following registry entries:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Session Manager\AppCertDlls
{random file name} = "%System%\{random file name 2}.dll"

Stolen Information

This spyware sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}wsixlatam.ru/P4ND3M1CB00BF4C3/{random string}/
  • http://{BLOCKED}ube.ru/P4ND3M1CB00BF4C3/{random string}/

Other Details

This spyware deletes the initially executed copy of itself

NOTES:

It hooks the following WININET.DLL exported functions when the DLL component is loaded in IEXPLORE.EXE to monitor network traffic:

  • InternetReadFile
  • InternetReadFileExA
  • InternetReadFileExW
  • HttpSendRequestA
  • HttpSendRequestW
  • HttpQueryInfoA
  • HttpQueryInfoW
  • HttpAddRequestHeadersA
  • HttpAddRequestHeadersW
  • InternetConnectA
  • InternetConnectW
  • InternetQueryDataAvailable

It hooks the following NSS3.DLL exported functions when the DLL component is loaded in FIREFOX.EXE to monitor network traffic:

  • PR_Read
  • PR_Write
  • PR_Close

It hooks the following WS2_32.DLL and KERNEL32.DLL exported functions when the DLL component is loaded in CHROME.EXE to monitor network traffic:

  • WSARecv
  • WSASend
  • closesocket
  • LoadLibraryExW

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.686.01
FIRST VSAPI PATTERN DATE: 25 Mar 2014

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

Identify and terminate files detected as TSPY_URSNIF.YNJ

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Delete this registry key

[ Learn More ]

=Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\SOFTWARE
    • Microshit

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 file name} = "%All Users Profile%\Application Data\{random file name}.exe"
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\AppCertDlls
    • {random file name} = "%System%\{random file name 2}.dll"

Step 5

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