TROJ_AGENT_024086.TOMB

May 06, 2013
 ALIASES:

Trojan:Win32/Enosch.A (Microsoft); Spy-Agent.gg (McAfee); W32.SillyFDC (Symantec); Trojan-Dropper.Win32.Agent.fzcd (Kaspersky); Trojan.Win32.Generic!SB.0 (Sunbelt); Gen:Variant.Strictor.2683 (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:

1,732,038 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Jun 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:

  • %User Profile%\gupd.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 Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
gtalkupdate = "%User Profile%\gupd.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Chilkat Software, Inc.

HKEY_CURRENT_USER\Software\Chilkat Software, Inc.\
ChilkatMail

HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.

HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.\
ChilkatMail

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Chilkat Software, Inc.\
ChilkatMail
Key30 = "85UUai7dJKVqvzz3coCdm4Gi2D2CFCeZWi2BzscNZ+A="

HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.\
ChilkatMail
Key30 = "85UUai7dJKVqvzz3coCdm4Gi2D2CFCeZWi2BzscNZ+A="

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://www.{BLOCKED}e.com/index.html

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_CURRENT_USER\Software
    • Chilkat Software, Inc.
  • In HKEY_CURRENT_USER\Software\Chilkat Software, Inc.
    • ChilkatMail
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • Chilkat Software, Inc.
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.
    • ChilkatMail

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • gtalkupdate = "%User Profile%\gupd.exe"
  • In HKEY_CURRENT_USER\Software\Chilkat Software, Inc.\ChilkatMail
    • Key30 = "85UUai7dJKVqvzz3coCdm4Gi2D2CFCeZWi2BzscNZ+A="
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.\ChilkatMail
    • Key30 = "85UUai7dJKVqvzz3coCdm4Gi2D2CFCeZWi2BzscNZ+A="

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_AGENT_024086.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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