ALIASES:

Backdoor:Win32/Zegost.P (Microsoft); Backdoor.Win32.Zegost.n (v) (Sunbelt); Trojan.Generic.KDV.353483 (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: 180,224 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 23 Sep 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:

  • %Temp%\svchast.exe 201292332845.exe

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

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
:\WINDOWS\Temp\svchast.exe 201292332845.exe = "{random characters}"

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

Restart in Safe Mode

[ 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • :\WINDOWS\Temp\svchast.exe 201292332845.exe = "{random characters}"

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_AGENT_044408.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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