TROJ_SHEUR.ARU


 ALIASES:

Trojan:Win32/VB.LN (Microsoft); Generic Dropper!ol (McAfee); W32.SillyFDC (Symantec); Trojan.Win32.Agent.aoru, Trojan.Win32.Agent.aoru (Kaspersky); Virus.Win32.Sality.gen.am (v) (Sunbelt); Trojan.Generic.1611386 (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.

  TECHNICAL DETAILS

File Size:

139,264 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Apr 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.

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
smss = "%Windows%\security\smss.exe"

Other System Modifications

This Trojan deletes the following files:

  • %Windows%\security\smss.exe
  • %Windows%\sysproc.dll

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0\
FLAGS

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0\
0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0\
0\win32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0\
HELPDIR

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}\ProxyStubClsid

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}\ProxyStubClsid32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}\TypeLib

HKEY_CLASSES_ROOT\CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}\InprocServer32

HKEY_CLASSES_ROOT\SysProc.Afire

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}\Control

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{248DD890-BB45-11CF-9ABC-0080C7E7B78D}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{248DD890-BB45-11CF-9ABC-0080C7E7B78D}\1.0\
0

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}\TypeLib
Version = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
ProgID = "SysProc.Afire"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}\InprocServer32
ThreadingModel = "Apartment"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
TypeLib = "{2DF27952-C9DD-47CC-961E-CFF592E7A320}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
VERSION = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
SysProc.Afire
Clsid = "{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
ProxyStubClsid = "{00020424-0000-0000-C000-000000000046}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
ProxyStubClsid32 = "{00020424-0000-0000-C000-000000000046}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}\InprocServer32
ThreadingModel = "Apartment"

(Note: The default value data of the said registry entry is Apartment.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{248DD892-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
Version = "1.0"

(Note: The default value data of the said registry entry is 1.0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{248DD893-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
Version = "1.0"

(Note: The default value data of the said registry entry is 1.0.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD897-BB45-11CF-9ABC-0080C7E7B78D}

Dropping Routine

This Trojan drops the following files:

  • %Windows%\syskernel.dll

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

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

[ Learn More ]

Step 3

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\SOFTWARE\Classes\TypeLib
    • {2DF27952-C9DD-47CC-961E-CFF592E7A320}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}
    • 1.0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0
    • FLAGS
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0
    • 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0\0
    • win32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{2DF27952-C9DD-47CC-961E-CFF592E7A320}\1.0
    • HELPDIR
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
    • {A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
    • ProxyStubClsid
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
    • ProxyStubClsid32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
    • TypeLib
  • In HKEY_CLASSES_ROOT\CLSID
    • {CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
    • InprocServer32
  • In HKEY_CLASSES_ROOT
    • SysProc.Afire
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}
    • Control
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
    • {248DD890-BB45-11CF-9ABC-0080C7E7B78D}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{248DD890-BB45-11CF-9ABC-0080C7E7B78D}\1.0
    • 0

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • smss = "%Windows%\security\smss.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}\TypeLib
    • Version = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
    • ProgID = "SysProc.Afire"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
    • TypeLib = "{2DF27952-C9DD-47CC-961E-CFF592E7A320}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}
    • VERSION = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\SysProc.Afire
    • Clsid = "{CC1356E6-C5AA-4BA6-927D-FBBEA3B11E8A}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
    • ProxyStubClsid = "{00020424-0000-0000-C000-000000000046}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{A424219B-3F96-4D9A-86A3-DE5A8BB9C00C}
    • ProxyStubClsid32 = "{00020424-0000-0000-C000-000000000046}"

Step 5

Restore these modified registry values

[ Learn More ]

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\Classes\CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}\InprocServer32
    • From: ThreadingModel = "Apartment"
      To: ThreadingModel = ""Apartment""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{248DD892-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
    • From: Version = "1.0"
      To: Version = ""1.0""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{248DD893-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
    • From: Version = "1.0"
      To: Version = ""1.0""

Step 6

Search and delete this file

[ Learn More ]
There may be some 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.
  • %Windows%\syskernel.dll

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SHEUR.ARU. 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 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.

  • %Windows%\security\smss.exe
  • %Windows%\sysproc.dll

Step 9

Restore these deleted registry keys/values from backup

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

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {248DD896-BB45-11CF-9ABC-0080C7E7B78D}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {248DD897-BB45-11CF-9ABC-0080C7E7B78D}


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