arrow_back
search
close

TROJ_WERDLOD.A

December 16, 2014
 Analysis by: Adrian Cofreros
 ALIASES:

Trojan-Dropper.Win32.Injector.laci(Kaspersky)

 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:

Spammed via email, Downloaded from the Internet, Dropped by other malware


This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

It does not have any backdoor routine.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE, RTF

Memory Resident:

No

Initial Samples Received Date:

09 Dec 2014

Payload:

Closes windows, Downloads files

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 file(s)/component(s):

  • %All Users Profile%\cert{value}.der - install certificate on trusted root certificate store, will be deleted after

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 System Modifications

This Trojan modifies the following file(s):

  • {firefox path}\prefs.js

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
AutoConfigURL = "http://{BLOCKED}.7.{BLOCKED}3.68:8080/proxy.pac"

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}orn.tv/hookersnord.com/wp-includes/js/imgareaselect/gkcjrmgkrcjgcrtcrtrccr/crtbtybtyvtytytbyt.exe

It saves the files it downloads using the following names:

  • %All Users Profile%\Microsoft-KB{random}.exe - detected as TROJ_DOFOIL.EJSO

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

NOTES:

It access the following legitimate URLs to download file:

  • http://download.microsoft.com/download/0/6/1/061F001C-8752-4600-A198-53214C69B51F/dotnetfx35setup.exe
  • http://download.microsoft.com/download/7/3/4/7345bb7d-0b07-40e8-9480-5b8c55b9c8b7/WindowsXP-KB926139-v2-x86-ENU.exe
  • http://download.microsoft.com/download/c/7/5/c750f1af-8940-44b6-b9eb-d74014e552cd/adminpak.exe

It saves the downloaded file from those legitimate URLs using the following:

  • %All Users Profile%\WindowsXP-KB{random}.exe

The legitimate files are install packages which are required to perform some of its routines.

It connects to the following to update count hits:

  • http://www.{BLOCKED}unter.com/counter.php?vtrtvrvtrtvertvr
  • http://www.{BLOCKED}unter.com/counter.php?tcrcrcerererwbvbbrtdf

It checks for the following processes:

  • VBoxService
  • VBoxTray
  • Proxifier
  • prl_cc
  • prl_tools
  • vmusrvc
  • vmsrvc
  • vmtoolsd

It checks for specific domains on cookies and history.

When accessing specific domains, users access the malicious SOCKS server using the file from the following:

  • http://{BLOCKED}.{BLOCKED}.143.68:8080/proxy.pac

The modified 'prefs.js' contains the following:

  • user_pref(network.proxy.type.2)
  • user_pref(network.proxy.autoconfig_url http://BLOCKED}.{BLOCKED}.143.68:8080/proxy.pac)

It terminates the following processes:

  • chrome.exe
  • firefox.exe
  • iexplore.exe

It imports rogue root certificates to browsers (Internet Explorer, Firefox).

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.338.04

FIRST VSAPI PATTERN DATE:

11 Dec 2014

VSAPI OPR PATTERN File:

11.339.04

VSAPI OPR PATTERN Date:

12 Dec 2014

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 malware/grayware files dropped/downloaded by TROJ_WERDLOD.A. (Note: Please skip this step if the threats listed below have already been removed.)

    • TROJ_DOFOIL.EJSO

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\Internet Settings
    • AutoConfigURL = "http://{BLOCKED}.7.{BLOCKED}3.68:8080/proxy.pac"

Step 5

Search and delete these files

[ Learn More ]
There may be some 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.
  • %All Users Profile%\WindowsXP-KB{random}.exe
  • %All Users Profile%\cert{value}.der

Step 6

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

Step 7

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.

  • {firefox path}\prefs.js


Did this description help? Tell us how we did.