TROJ_AGENT_054031.TOMB

May 28, 2013
 ALIASES:

PWS:Win32/Zbot.gen!AM (Microsoft); PWS-Zbot-FATG!F275F2650753 (McAfee); Trojan.Zbot (Symantec); Trojan-Spy.Win32.Zbot.kbns (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); ERROR (FSecure); Trojan horse PSW.Generic10.CPFC (AVG)

 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:

404,992 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 May 2013

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 creates the following folders:

  • %User Profile%\Application Data\Tojay

(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
{58C4EBA0-47A8-AD40-8C85-A85A94978B48} = "%User Profile%\Tojay\enufto.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Zayf

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Zayf
9185292 = "rBmaVUfw0MWmLg==?_CHAR(0x05)_?"

HKEY_CURRENT_USER\Software\Microsoft\
Zayf
cccdb6g = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
26859:UDP = "26859:UDP:*:Enabled:UDP 26859"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
28276:TCP = "28276:TCP:*:Enabled:TCP 28276"

HKEY_CURRENT_USER\Software\Microsoft\
Zayf
1ee56h7g = "JHH7VUCeuMWULsuk_CHAR(0x05)_re?r?red."

HKEY_CURRENT_USER\Software\Microsoft\
Zayf
47d5dh1 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager
Server ID = "4"

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\Tojay
  • %User Profile%\Tojay\enufto.exe
  • %Application Data%\opawx.ymr

(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.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

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

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\Microsoft
    • Zayf

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
    • {58C4EBA0-47A8-AD40-8C85-A85A94978B48} = "%User Profile%\Tojay\enufto.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Zayf
    • 9185292 = "rBmaVUfw0MWmLg==?_CHAR(0x05)_?"
  • In HKEY_CURRENT_USER\Software\Microsoft\Zayf
    • cccdb6g = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 26859:UDP = "26859:UDP:*:Enabled:UDP 26859"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 28276:TCP = "28276:TCP:*:Enabled:TCP 28276"
  • In HKEY_CURRENT_USER\Software\Microsoft\Zayf
    • 1ee56h7g = "JHH7VUCeuMWULsuk_CHAR(0x05)_re?r?red."
  • In HKEY_CURRENT_USER\Software\Microsoft\Zayf
    • 47d5dh1 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager
    • Server ID = "4"

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.
  • %User Profile%\Application Data\Tojay
  • %User Profile%\Tojay\enufto.exe
  • %Application Data%\opawx.ymr

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.
  • %User Profile%\Application Data\Tojay

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_AGENT_054031.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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