Modified by: RonJay Kristoffer Caragay
ALIASES:

TrojanDropper:Win32/Vundo.AB (Microsoft); Trojan.Vundo (Symantec); RDN/Vundo!du (McAfee); Trojan.Vundo (Malwarebytes); W32/Vundo.FI (F-Prot); TR/Vundo.Gen (Avira)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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 may be downloaded from remote sites by other malware.

It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 997,744 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 09 Apr 2015
Payload: Connects to URLs/IPs, Drops files

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.

It may be downloaded from remote site(s) by the following malware:

Installation

This Trojan adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{random}

Autostart Technique

This Trojan creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
{random} = "{path}\{filename}.exe"

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random} = "{path}\{filename}.exe"

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{random 1}
{random 2} = "{random values}"

HKEY_CURRENT_USER\SOFTWARE\{random 1}
{random 2} = "{random values}"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\~unins{random}.bat ← delete malware's initially executed copy and itself
  • {path}\{filename}.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following website to send and receive information:

  • http://{BLOCKED}.{BLOCKED}.88.220/signin

However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself

NOTES:

It installs an adware using the following name:

  • {path}\{filename}.exe
  • where {path} are any of the following:
  • %Program Files%
  • %Application Data%
  • %System%
where {filename} is {system file + a character}.exe

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.594.03
FIRST VSAPI PATTERN DATE: 09 Apr 2015
VSAPI OPR PATTERN File: 11.595.00
VSAPI OPR PATTERN Date: 09 Apr 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove the malware/grayware file that dropped/downloaded TROJ_VUNDO.XPBL. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • JAVA_ZUPNIC.A

Step 4

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • {random} = "{path}\{filename}.exe"
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random} = "{path}\{filename}.exe"

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VUNDO.XPBL. 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 7

The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

  • HKEY_LOCAL_MACHINE\SOFTWARE\{random 1}
    • {random 2} = "{random values}"
  • In HKEY_CURRENT_USER\SOFTWARE\{random 1}
    • {random 2} = "{random values}"

Step 8

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