TROJ_UNRUY.SMT
TrojanDownloader:Win32/Unruy.C (Microsoft); Downloader-BPA.d (McAfee); Downloader (Symantec); Trojan-Clicker.Win32.Cycler.ajsz (Kaspersky); Trojan-Downloader.Win32.Unruy.C (v) (Sunbelt); Trojan.Generic.4749054 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
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.
TECHNICAL DETAILS
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.
Installation
This Trojan creates the following folders:
- %Program Files%\Adobe
- %Program Files%\Internet Explorer
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Adobe_Reader = "%Program Files%\internet explorer\wmpscfgs.exe"
Other System Modifications
This Trojan modifies the following file(s):
- %Program Files%\messenger\msmsgs.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
Name = "iexplore.exe"
(Note: The default value data of the said registry entry is mshta.exe.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
ID = 4117b81
(Note: The default value data of the said registry entry is 41107b3f.)
Dropping Routine
This Trojan drops the following files:
- %Program Files%\adobe\acrotray .exe
- %Program Files%\adobe\acrotray.exe
- %Program Files%\internet explorer\wmpscfgs.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
This report is generated via an automated analysis system.
SOLUTION
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
Restart in Safe Mode
Step 3
Delete this registry value
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\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Adobe_Reader="%Program Files%\internet explorer\wmpscfgs.exe"
Step 4
Restore these modified registry values
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_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
- From: Name="iexplore.exe"
To: Name=mshta.exe
- From: Name="iexplore.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
- From: ID=4117b81
To: ID=41107b3f
- From: ID=4117b81
Step 5
Search and delete these folders
- %Program Files%\Adobe
- %Program Files%\Internet Explorer
Step 6
Search and delete these components
- %Program Files%\adobe\acrotray .exe
- %Program Files%\adobe\acrotray.exe
- %Program Files%\internet explorer\wmpscfgs.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_UNRUY.SMT. 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 8
Restore deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/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.
- %Program Files%\messenger\msmsgs.exe
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