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TROJ_AGENT.OM

April 04, 2013
 ALIASES:

TrojanDownloader:Win32/Agent (Microsoft); Downloader-LE.gen (McAfee); SecurityRisk.Downldr (Symantec); PAK:UPX, Trojan-Downloader.Win32.Agent.lg (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Downloader.Agent.LG (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:

109,568 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Aug 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:

  • %System%\bvhmkxg\2.tmp

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It creates the following folders:

  • %System%\bvhmkxg

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

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
apfgoxxt = "%System%\bvhmkxg\apfgoxxt.exe"

Other System Modifications

This Trojan deletes the following files:

  • %System%\bvhmkxg\apfgoxxt.exe
  • %User Temp%\1.tmp
  • %User Temp%\3.tmp
  • %Temp%\0aug.exe
  • %Temp%\4.tmp
  • %Temp%\1aug.exe
  • %Temp%\5.tmp
  • %Temp%\2aug.exe
  • %Temp%\6.tmp
  • %Temp%\3aug.exe
  • %Temp%\7.tmp
  • %Temp%\4aug.exe
  • %Temp%\8.tmp
  • %Temp%\5aug.exe
  • %Temp%\9.tmp
  • %Temp%\6aug.exe
  • %Temp%\A.tmp
  • %Temp%\7aug.exe
  • %Temp%\B.tmp
  • %Temp%\8aug.exe
  • %Temp%\C.tmp
  • %Temp%\9aug.exe
  • %Temp%\D.tmp

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %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.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)

It adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{0EA4F95A-7D52-9FB2-BBB8-7B71E431C60C}\
Version

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Version

HKEY_CLASSES_ROOT\CLSID\{1E6D34F1-D1F6-D8B8-1670-15328045EFE0}

HKEY_CLASSES_ROOT\CLSID\{0538E5BF-1EC8-FFF6-C6AC-541522BDB335}

HKEY_CLASSES_ROOT\CLSID\{0F039A09-537E-529F-E091-87F17397A9A1}\
InprocServer32

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{0538E5BF-1EC8-FFF6-C6AC-541522BDB335}
Release = "10005"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
NID = "5aa65ef1b82c4df280f937adb00ca4b3"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion
ProductId = "55274-640-1799622-47257"

(Note: The default value data of the said registry entry is 76487-640-0059266-23340.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion
ProductId = "55274-640-1799622-47257"

(Note: The default value data of the said registry entry is 76487-640-0059266-23340.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Connections
DefaultConnectionSettings = "{random values}"

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

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://aug.{BLOCKED}o.com/user.dat
  • http://aug.{BLOCKED}o.com/timestamp.php
  • http://aug.{BLOCKED}o.com/aug/stats/aug_8.html?{random characters}
  • http://aug.{BLOCKED}o.com/aug/maps/map.html?{random characters}

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_CLASSES_ROOT\CLSID\{0EA4F95A-7D52-9FB2-BBB8-7B71E431C60C}
    • Version
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • Version
  • In HKEY_CLASSES_ROOT\CLSID
    • {1E6D34F1-D1F6-D8B8-1670-15328045EFE0}
  • In HKEY_CLASSES_ROOT\CLSID
    • {0538E5BF-1EC8-FFF6-C6AC-541522BDB335}
  • In HKEY_CLASSES_ROOT\CLSID\{0F039A09-537E-529F-E091-87F17397A9A1}
    • InprocServer32

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
    • apfgoxxt = "%System%\bvhmkxg\apfgoxxt.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{0538E5BF-1EC8-FFF6-C6AC-541522BDB335}
    • Release = "10005"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • NID = "5aa65ef1b82c4df280f937adb00ca4b3"

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\Microsoft\Windows NT\CurrentVersion
    • From: ProductId = "55274-640-1799622-47257"
      To: ProductId = ""76487-640-0059266-23340""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
    • From: ProductId = "55274-640-1799622-47257"
      To: ProductId = ""76487-640-0059266-23340""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyEnable = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections
    • From: DefaultConnectionSettings = "{random values}"
      To: DefaultConnectionSettings = ""{random values}""

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System%\bvhmkxg

Step 7

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

  • %System%\bvhmkxg\apfgoxxt.exe
  • %User Temp%\1.tmp
  • %User Temp%\3.tmp
  • %Temp%\0aug.exe
  • %Temp%\4.tmp
  • %Temp%\1aug.exe
  • %Temp%\5.tmp
  • %Temp%\2aug.exe
  • %Temp%\6.tmp
  • %Temp%\3aug.exe
  • %Temp%\7.tmp
  • %Temp%\4aug.exe
  • %Temp%\8.tmp
  • %Temp%\5aug.exe
  • %Temp%\9.tmp
  • %Temp%\6aug.exe
  • %Temp%\A.tmp
  • %Temp%\7aug.exe
  • %Temp%\B.tmp
  • %Temp%\8aug.exe
  • %Temp%\C.tmp
  • %Temp%\9aug.exe
  • %Temp%\D.tmp


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