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TROJ_AGENT_028381.TOMB

November 26, 2012
 ALIASES:

Trojan:Win32/HistBoader.gen!A (Microsoft); Generic VB.kf (McAfee); Trojan.Gen (Symantec); Worm.Win32.AutoRun.dfyl, Worm.Win32.AutoRun.dfyl (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Worm.Generic.371719 (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 disables Task Manager, Registry Editor, and Folder Options.

  TECHNICAL DETAILS

File Size:

253,952 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Nov 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_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
csrss = "%User Profile%\Microsoft\csrss.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
csrss = "%User Profile%\Microsoft\csrss.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,%User Profile%\Microsoft\csrss.exe"

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

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
Microzoft\88D2F234015A98BD7DFFCA9E2EC14234BAF8

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
Microzoft\88D2F234015A98BD7DFFCA9E2EC14234BAF8
Exacutible = "?ÏHñ_CHAR(0x16)__CHAR(0x10)_ð;¢"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrss = "%User Profile%\Microsoft\csrss.exe"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
Microzoft\88D2F234015A98BD7DFFCA9E2EC14234BAF8
FristSatrt = "?ùOú pÞ_CHAR(0x02)_°óÆû"

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
csrss = "%User Profile%\Microsoft\csrss.exe"

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

Identify and delete files detected as TROJ_AGENT_028381.TOMB using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware.

Step 4

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_CURRENT_USER\Software\VB and VBA Program Settings\Microzoft
    • 88D2F234015A98BD7DFFCA9E2EC14234BAF8
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run

Step 5

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
    • csrss = "%User Profile%\Microsoft\csrss.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • csrss = "%User Profile%\Microsoft\csrss.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\Microzoft\88D2F234015A98BD7DFFCA9E2EC14234BAF8
    • Exacutible = "?ÏHñ_CHAR(0x16)__CHAR(0x10)_ð;¢"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • csrss = "%User Profile%\Microsoft\csrss.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\Microzoft\88D2F234015A98BD7DFFCA9E2EC14234BAF8
    • FristSatrt = "?ùOú pÞ_CHAR(0x02)_°óÆû"

Step 6

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = "%System%\userinit.exe,%User Profile%\Microsoft\csrss.exe"
      To: Userinit = ""%Windows%\system32\userinit.exe,""

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT_028381.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.


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