WORM_PASTA.SMX
Trojan:Win32/Startpage.gen!A (Microsoft); StartPage-LC (McAfee); W32.SillyFDC (Symantec); Trojan.Win32.Pasta.kri, Trojan.Win32.Pasta.kri (Kaspersky); Virus.Win32.Virut.ce.4 (v) (Sunbelt); Trojan.StartPage.ZSB (FSecure)
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm 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
244,736 bytes
EXE
Yes
30 Sep 2011
Arrival Details
This worm 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 worm drops the following copies of itself into the affected system:
- %User Profile%\Application Data\cssrs.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
TINTIMG = "%User Profile%\Application Data\cssrs.exe"
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\AboutURLs
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SuperHidden
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SuperHidden
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\HideFileExt
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}6.info"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\AboutURLs
blank = "http://www.{BLOCKED}6.info"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\AboutURLs
Tabs = "http://www.{BLOCKED}6.info"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\AboutURLs
Tabs = "http://www.{BLOCKED}6.info"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = 1
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SuperHidden
CheckedValue = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SuperHidden
CheckedValue = 1
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\HideFileExt
CheckedValue = 1
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}6.info"
(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home.)
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}6.info"
(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}6.info"
(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\AboutURLs
blank = "http://www.{BLOCKED}6.info"
(Note: The default value data of the said registry entry is res://mshtml.dll/blank.htm.)
Dropping Routine
This worm drops the following files:
- %User Startup%\cssrs.exe
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
This report is generated via an automated analysis system.
SOLUTION
9.200
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 key
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\Internet Explorer
- AboutURLs
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden
- SHOWALL
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden
- SuperHidden
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden
- SuperHidden
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder
- HideFileExt
Step 4
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
- TINTIMG="%User Profile%\Application Data\cssrs.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Default_Page_URL="http://www.{BLOCKED}6.info"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\AboutURLs
- blank="http://www.{BLOCKED}6.info"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\AboutURLs
- Tabs="http://www.{BLOCKED}6.info"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\AboutURLs
- Tabs="http://www.{BLOCKED}6.info"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- Hidden=2
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- HideFileExt=1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SuperHidden
- CheckedValue=1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SuperHidden
- CheckedValue=1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\HideFileExt
- CheckedValue=1
Step 5
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\Internet Explorer\Main
- From: Start Page="http://www.{BLOCKED}6.info"
To: Start Page=http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home
- From: Start Page="http://www.{BLOCKED}6.info"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- From: Start Page="http://www.{BLOCKED}6.info"
To: Start Page=http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome
- From: Start Page="http://www.{BLOCKED}6.info"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
- From: Default_Page_URL="http://www.{BLOCKED}6.info"
To: Default_Page_URL=http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome
- From: Default_Page_URL="http://www.{BLOCKED}6.info"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\AboutURLs
- From: blank="http://www.{BLOCKED}6.info"
To: blank=res://mshtml.dll/blank.htm
- From: blank="http://www.{BLOCKED}6.info"
Step 6
Search and delete this file
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PASTA.SMX. 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.
Did this description help? Tell us how we did.