Threat Encyclopedia

PE_LICAT.A-O

Publish date: July 27, 2013

ANALYSIS BY

JessaD

     MODIFIED BY

     Sabrina Lei Sioting


ALIASES:

PWS:Win32/Zbot.gen!AJ (Microsoft), PWS-Zbot.gen.ds (McAfee), Mal/Zbot-HX (Sophos), W32/Zbot.AT!tr (Fortinet), Trojan-Spy.Win32.Zbot (Ikarus),

PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type:File infector

  • Destructiveness:No

  • Encrypted:

  • In the wild: Yes

OVERVIEW

Infection Channel:

Infects files


This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It inserts its codes into unused space in files.

It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.

It attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

TECHNICAL DETAILS

File Size:

214,528 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

06 Sep 2010

Payload:

Modifies files, Steals information, Compromises system security

Arrival Details

This file infector 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 file infector drops the following copies of itself into the affected system:

  • %Application Data%\{random1}\{random}.exe

(Note: %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.)

It drops the following component file(s):

  • %Application Data%\{random2}\{random}.{3 random alpha character extension name}

(Note: %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.)

It injects itself into the following processes running in the affected system's memory:

  • explorer.exe

It creates the following folders:

  • %Application Data%\{random1}
  • %Application Data%\{random2}

(Note: %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.)

Autostart Technique

This file infector adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "%Application Data%\{random1}\{random}.exe"

Other System Modifications

This file infector adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
{random}

File Infection

This file infector infects the following file types:

  • .EXE

It inserts its codes into unused space in files.

It avoids infecting folders containing the following strings:

  • %Program Files%
  • %System%
  • %User Application Data%
  • %Windows%

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %System% is the Windows system folder, which is usually C:\Windows\System32.. %Windows% is the Windows folder, which is usually C:\Windows.)

Backdoor Routine

This file infector opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.

Information Theft

This file infector attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

NOTES:

This worm generates pseudorandom alpha characters using a randomizing function, which is computed from the current UTC system date and time. It then creates 800 domain names at every execution based from the generated characters and appends any of the following to complete a URL:

  • .biz/forum
  • .org/forum
  • .info/forum
  • .net/forum
  • .com/forum

It then connects to its generated URLs to donwload file(s). However, as of this writing, the said sites are inaccessible.

Infected files are detected as PE_LICAT.A.

SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

7.524.03

FIRST VSAPI PATTERN DATE:

07 Oct 2010

VSAPI OPR PATTERN File:

7.531.00

VSAPI OPR PATTERN Date:

11 Oct 2010

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

Remove the malware/grayware file dropped/downloaded by PE_LICAT.A-O

Step 3

Scan your computer with your Trend Micro product and note files detected as PE_LICAT.A-O

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CURRENT_USER\Software\Microsoft
    • {random}

Step 6

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
    • {GUID} = "%Application Data%\{random1}\{random}.exe"

Step 7

Search and delete these folders

[ 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.
  • %Application Data%\{random1}
  • %Application Data%\{random2}

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_LICAT.A-O. 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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