Threat Encyclopedia

BKDR_URSNIF.DN

ANALYSIS BY

Michael Cabel


ALIASES:

TrojanSpy:Win32/Ursnif.gen!F (Microsoft); BehavesLike.Win32.Malware.mfc (mx-v) (Sunbelt)

PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type:Backdoor

  • Destructiveness:No

  • Encrypted: Yes

  • In the wild: Yes

OVERVIEW

TECHNICAL DETAILS

SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.452.04

FIRST VSAPI PATTERN DATE:

10 Oct 2012

VSAPI OPR PATTERN File:

9.453.00

VSAPI OPR PATTERN Date:

11 Oct 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by BKDR_URSNIF.DN

Step 3

Identify and delete files detected as BKDR_URSNIF.DN using the Recovery Console

[ 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
    • nah_Shell = "%User Profile%\nah_{random}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • nah_id = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • nah_options = "{random values}"

Step 5

Search and delete these files

[ Learn More ]
There may be some component 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.
{folder location}\chrome\amba.jar

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_URSNIF.DN. 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

Restore these deleted files from backup

*Note: Only Microsoft-related keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.


{folder path}\chrome\browser.manifest


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