TROJ_URSNIF.BG

October 13, 2012

ALIASES:

PWS-Zbot.gen.yn (McAfee); Trojan-Dropper.Win32.Daws.argm (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Backdoor.Bot.152234 (FSecure)

PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

OVERALL RISK RATING:

DAMAGE POTENTIAL:

DISTRIBUTION POTENTIAL:

REPORTED INFECTION:

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes

OVERVIEW

This Trojan 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: 194,560 bytes

File Type: EXE

Memory Resident: No

Initial Samples Received Date: 05 Jul 2012

Arrival Details

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

Other System Modifications

This Trojan deletes the following files:

%User Profile%\Cookies\index.dat
%Desktop%.ini
%User Profile%\History.IE5\index.dat
%User Profile%\MSHist012010121320101220\index.dat
%User Profile%\MSHist012010122820101229\index.dat
%User Profile%\MSHist012010122920101230\index.dat
%User Profile%\MSHist012011010220110103\index.dat
%Temporary Internet Files%\Content.IE5\2TPM8950\10[1].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\16[1].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\bottom_right3[1].png
%Temporary Internet Files%\Content.IE5\2TPM8950\box01[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\box02[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\box08[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\desktop.ini
%Temporary Internet Files%\Content.IE5\2TPM8950\header00b[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\jquery-1.4.2.min[1].js
%Temporary Internet Files%\Content.IE5\2TPM8950\report_image[1].png
%Temporary Internet Files%\Content.IE5\2TPM8950\table_left3[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\10[1].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\box07[1].gif
%Temporary Internet Files%\Content.IE5\4H9MXTT9\CalendarPopup[1].js
%Temporary Internet Files%\Content.IE5\4H9MXTT9\desktop.ini
%Temporary Internet Files%\Content.IE5\4H9MXTT9\dropdown[1].jpg
%Temporary Internet Files%\Content.IE5\4H9MXTT9\footer00[1].gif
%Temporary Internet Files%\Content.IE5\4H9MXTT9\header02[1].jpg
%Temporary Internet Files%\Content.IE5\4H9MXTT9\import[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\table_bottom3[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\table_top3[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\transpix[1].gif
%Temporary Internet Files%\Content.IE5\desktop.ini
%Temporary Internet Files%\Content.IE5\index.dat
%Temporary Internet Files%\Content.IE5\SMCZPN4M\10[1].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\background[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\box03[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\box04[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\box06[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\config[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\desktop.ini
%Temporary Internet Files%\Content.IE5\SMCZPN4M\edit_icon_thumb[1].png
%Temporary Internet Files%\Content.IE5\SMCZPN4M\jquery-ui-1.8.custom.min[1].js
%Temporary Internet Files%\Content.IE5\SMCZPN4M\sandbox[1].css
%Temporary Internet Files%\Content.IE5\SMCZPN4M\top_right3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[5].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\bottom_left3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\box09[1].gif
%Temporary Internet Files%\Content.IE5\X9QQH2D9\delete_icon_thumb[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\desktop.ini
%Temporary Internet Files%\Content.IE5\X9QQH2D9\jquery.jeditable.mini[1].js
%Temporary Internet Files%\Content.IE5\X9QQH2D9\overlib[1].js
%Temporary Internet Files%\Content.IE5\X9QQH2D9\sunbeltlabs_logo[1].jpg
%Temporary Internet Files%\Content.IE5\X9QQH2D9\table_right3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\top_left3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\users[1].png
%Temporary Internet Files%\desktop.ini

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.)

It deletes the following folders:

%User Profile%\History.IE5\MSHist012010121320101220
%User Profile%\History.IE5\MSHist012010122820101229
%User Profile%\History.IE5\MSHist012010122920101230
%User Profile%\History.IE5\MSHist012011010220110103
%User Profile%\History\History.IE5
%Temporary Internet Files%\Content.IE5\2TPM8950
%Temporary Internet Files%\Content.IE5\4H9MXTT9
%Temporary Internet Files%\Content.IE5\SMCZPN4M
%Temporary Internet Files%\Content.IE5\X9QQH2D9
%Temporary Internet Files%\Content.IE5

It adds the following registry keys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Session Manager\AppCertDlls

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager\AppCertDlls
cidaconv = "%System%\cmdltvwr.dll"

Dropping Routine

This Trojan drops the following files:

%System Root%\52734.bat

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

SOLUTION

Minimum Scan Engine: 9.200

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

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_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager
- AppCertDlls

Step 3

Delete this registry value

[ Learn More ]

In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\AppCertDlls
- cidaconv = "%System%\cmdltvwr.dll"

Step 4

Search and delete this file

[ 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.

%System Root%\52734.bat

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_URSNIF.BG. 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 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

%User Profile%\Cookies\index.dat
%Desktop%.ini
%User Profile%\History.IE5\index.dat
%User Profile%\MSHist012010121320101220\index.dat
%User Profile%\MSHist012010122820101229\index.dat
%User Profile%\MSHist012010122920101230\index.dat
%User Profile%\MSHist012011010220110103\index.dat
%Temporary Internet Files%\Content.IE5\2TPM8950\10[1].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\16[1].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\2TPM8950\bottom_right3[1].png
%Temporary Internet Files%\Content.IE5\2TPM8950\box01[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\box02[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\box08[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\desktop.ini
%Temporary Internet Files%\Content.IE5\2TPM8950\header00b[1].gif
%Temporary Internet Files%\Content.IE5\2TPM8950\jquery-1.4.2.min[1].js
%Temporary Internet Files%\Content.IE5\2TPM8950\report_image[1].png
%Temporary Internet Files%\Content.IE5\2TPM8950\table_left3[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\10[1].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\4H9MXTT9\box07[1].gif
%Temporary Internet Files%\Content.IE5\4H9MXTT9\CalendarPopup[1].js
%Temporary Internet Files%\Content.IE5\4H9MXTT9\desktop.ini
%Temporary Internet Files%\Content.IE5\4H9MXTT9\dropdown[1].jpg
%Temporary Internet Files%\Content.IE5\4H9MXTT9\footer00[1].gif
%Temporary Internet Files%\Content.IE5\4H9MXTT9\header02[1].jpg
%Temporary Internet Files%\Content.IE5\4H9MXTT9\import[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\table_bottom3[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\table_top3[1].png
%Temporary Internet Files%\Content.IE5\4H9MXTT9\transpix[1].gif
%Temporary Internet Files%\Content.IE5\desktop.ini
%Temporary Internet Files%\Content.IE5\index.dat
%Temporary Internet Files%\Content.IE5\SMCZPN4M\10[1].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\SMCZPN4M\background[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\box03[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\box04[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\box06[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\config[1].gif
%Temporary Internet Files%\Content.IE5\SMCZPN4M\desktop.ini
%Temporary Internet Files%\Content.IE5\SMCZPN4M\edit_icon_thumb[1].png
%Temporary Internet Files%\Content.IE5\SMCZPN4M\jquery-ui-1.8.custom.min[1].js
%Temporary Internet Files%\Content.IE5\SMCZPN4M\sandbox[1].css
%Temporary Internet Files%\Content.IE5\SMCZPN4M\top_right3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[1].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[2].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[3].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[4].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[5].htm
%Temporary Internet Files%\Content.IE5\X9QQH2D9\bottom_left3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\box09[1].gif
%Temporary Internet Files%\Content.IE5\X9QQH2D9\delete_icon_thumb[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\desktop.ini
%Temporary Internet Files%\Content.IE5\X9QQH2D9\jquery.jeditable.mini[1].js
%Temporary Internet Files%\Content.IE5\X9QQH2D9\overlib[1].js
%Temporary Internet Files%\Content.IE5\X9QQH2D9\sunbeltlabs_logo[1].jpg
%Temporary Internet Files%\Content.IE5\X9QQH2D9\table_right3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\top_left3[1].png
%Temporary Internet Files%\Content.IE5\X9QQH2D9\users[1].png
%Temporary Internet Files%\desktop.ini

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TROJ_URSNIF.BG

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TECHNICAL DETAILS

SOLUTION

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