TROJ_AGENT_051069.TOMB


 ALIASES:

PWS:Win32/Simda.AF (Microsoft); Generic PWS.y!1ok (McAfee); Trojan.Gen (Symantec); Backdoor.Win32.Shiz.gggp (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Gen:Variant.Kazy.39463 (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:

300,544 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Dec 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.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %Windows%\apppatch\krsfys.exe

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

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
userinit = "%Windows%\apppatch\krsfys.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
userinit = "%System%\userinit.exe,%Windows%\apppatch\krsfys.exe,"

(Note: The default value data of the said registry entry is %Windows%\system32\userinit.exe,.)

Other System Modifications

This Trojan deletes the following files:

  • %User Temp%\1.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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
68ad0fd0 = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = "%Windows%\apppatch\krsfys.exe"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
System = "%Windows%\apppatch\krsfys.exe"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
LogSessionName = "stdout"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
Active = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
ControlFlags = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi\ImapiSvc
Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"

(Note: The default value data of the said registry entry is 8107d8e9-e323-49f5-bba2-abc35c243dca.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi\ImapiSvc
BitNames = "{random characters}"

(Note: The default value data of the said registry entry is ImapiDebugError ImapiDebugWarning ImapiDebugTrace ImapiDebugInfo ImapiDebugX ImapiDebugSort.)

Dropping Routine

This Trojan drops the following files:

  • %Windows%\apppatch\krsfys.exe
  • %Temp%\lwf1oybz.TMP

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

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Identify and delete files detected as TROJ_AGENT_051069.TOMB using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • userinit = "%Windows%\apppatch\krsfys.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • 68ad0fd0 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • run = "%Windows%\apppatch\krsfys.exe"

Step 4

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\Microsoft\Windows NT\CurrentVersion\Winlogon
    • System = "%Windows%\apppatch\krsfys.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • load = "%Windows%\apppatch\krsfys.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
    • From: LogSessionName = "stdout"
      To: LogSessionName = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
    • From: Active = "1"
      To: Active = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
    • From: ControlFlags = "1"
      To: ControlFlags = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi\ImapiSvc
    • From: Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"
      To: Guid = ""8107d8e9-e323-49f5-bba2-abc35c243dca""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi\ImapiSvc
    • From: BitNames = "{random characters}"
      To: BitNames = "" ImapiDebugError ImapiDebugWarning ImapiDebugTrace ImapiDebugInfo ImapiDebugX ImapiDebugSort""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: userinit = "%System%\userinit.exe,%Windows%\apppatch\krsfys.exe,"
      To: userinit = ""%Windows%\system32\userinit.exe,""

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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%\apppatch\krsfys.exe
  • %Temp%\lwf1oybz.TMP

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT_051069.TOMB. 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 7

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 Temp%\1.tmp


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