PE_CORELINK.A

July 02, 2013
 ALIASES:

Virus:Win32/Almanahe.A (Microsoft); PWS-Zbot.gen.cn (McAfee); W32.Virut.CF (Symantec); Virus.Win32.Alman.a (Kaspersky); Virus.Win32.Virut.ce (v) (Sunbelt); Win32.Almam.A (FSecure)

 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

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.

  TECHNICAL DETAILS

File Size:

163,840 bytes

File Type:

EXE

Initial Samples Received Date:

01 Oct 2011

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 creates the following folders:

  • %User Profile%\Microsoft\Dr Watson

(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.)

Other System Modifications

This file infector deletes the following files:

  • %System%\drivers\DKIS6.sys
  • %Windows%\AppPatch\apphelps.dll.update

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

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DrWatson
NumberOfCrashes = 1

(Note: The default value data of the said registry entry is 0.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting\DW

Dropping Routine

This file infector drops the following files:

  • %Windows%\linkinfo.dll
  • %System%\drivers\DKIS6.sys
  • %System%\drivers\RioDrvs.sys
  • %User Profile%\Dr Watson\drwtsn32.log
  • %User Profile%\Dr Watson\user.dmp
  • %Windows%\AppPatch\apphelps.dll.update
  • %Windows%\AppPatch\apphelps.dll

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

Other Details

This file infector connects to the following possibly malicious URL:

  • http://tj.{BLOCKED}ldwide.com/co.asp?{random characters}
  • http://tj.{BLOCKED}ldwide.com/co.asp?action=update&version=0
  • http://soft.{BLOCKED}ldwide.com/z.dat

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

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\DrWatson
    • From: NumberOfCrashes=1
      To: NumberOfCrashes=0

Step 3

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%\Microsoft\Dr Watson

Step 4

Search and delete these files

[ Learn More ]
There may be some component files 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.
  • %Windows%\linkinfo.dll
  • %System%\drivers\DKIS6.sys
  • %System%\drivers\RioDrvs.sys
  • %User Profile%\Dr Watson\drwtsn32.log
  • %User Profile%\Dr Watson\user.dmp
  • %Windows%\AppPatch\apphelps.dll.update
  • %Windows%\AppPatch\apphelps.dll

Step 5

Scan your computer with your Trend Micro product to clean files detected as PE_CORELINK.A. 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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