TROJ_SWISYN_0000013.TOMA

October 20, 2012
 ALIASES:

Trojan:Win32/Malex.gen!E (Microsoft); Swisyn.r (McAfee); Downloader (Symantec); Virus.Win32.Lamer.bz (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.3289028 (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 modifies files, disabling programs and applications from properly running.

  TECHNICAL DETAILS

File Size:

354,308 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

20 Oct 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 modifies the following files:

  • %System%\dllcache\iexplore.exe
  • %Program Files%\Internet Explorer\iexplore.exe
  • %System%\dllcache\cmd.exe
  • %System%\cmd.exe
  • %System%\dllcache\calc.exe
  • %System%\calc.exe
  • %System%\dllcache\cleanmgr.exe
  • %System%\cleanmgr.exe
  • %System%\dllcache\taskmgr.exe
  • %System%\taskmgr.exe
  • %System%\dllcache\regedit.exe
  • %Windows%\regedit.exe
  • %System%\dllcache\scrnsave.scr
  • %System%\scrnsave.scr

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%Windows%\svchost.exe"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\tro1350719250.exe
  • {malware path and file name}_uinst.exe
  • %Windows%\svchost.exe
  • %System%\dllcache\iexplore.exe.tmp
  • %Program Files%\Internet Explorer\iexplore.exe.tmp
  • %System%\dllcache\cmd.exe.tmp
  • %System%\cmd.exe.tmp
  • %System%\dllcache\calc.exe.tmp
  • %System%\calc.exe.tmp
  • %System%\dllcache\cleanmgr.exe.tmp
  • %System%\cleanmgr.exe.tmp
  • %System%\dllcache\taskmgr.exe.tmp
  • %System%\taskmgr.exe.tmp
  • %System%\dllcache\regedit.exe.tmp
  • %Windows%\regedit.exe.tmp
  • %System%\dllcache\scrnsave.scr.tmp
  • %System%\scrnsave.scr.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Restore this modified 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 NT\CurrentVersion\Windows
    • load = "%Windows%\svchost.exe"

Step 3

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.
  • %User Temp%\tro1350719250.exe
  • {malware path and file name}_uinst.exe
  • %Windows%\svchost.exe
  • %System%\dllcache\iexplore.exe.tmp
  • %Program Files%\Internet Explorer\iexplore.exe.tmp
  • %System%\dllcache\cmd.exe.tmp
  • %System%\cmd.exe.tmp
  • %System%\dllcache\calc.exe.tmp
  • %System%\calc.exe.tmp
  • %System%\dllcache\cleanmgr.exe.tmp
  • %System%\cleanmgr.exe.tmp
  • %System%\dllcache\taskmgr.exe.tmp
  • %System%\taskmgr.exe.tmp
  • %System%\dllcache\regedit.exe.tmp
  • %Windows%\regedit.exe.tmp
  • %System%\dllcache\scrnsave.scr.tmp
  • %System%\scrnsave.scr.tmp

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_SWISYN_0000013.TOMA. 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 5

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.

    • %System%\dllcache\iexplore.exe
    • %Program Files%\Internet Explorer\iexplore.exe
    • %System%\dllcache\cmd.exe
    • %System%\cmd.exe
    • %System%\dllcache\calc.exe
    • %System%\calc.exe
    • %System%\dllcache\cleanmgr.exe
    • %System%\cleanmgr.exe
    • %System%\dllcache\taskmgr.exe
    • %System%\taskmgr.exe
    • %System%\dllcache\regedit.exe
    • %Windows%\regedit.exe
    • %System%\dllcache\scrnsave.scr
    • %System%\scrnsave.scr


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