Threat Encyclopedia

TROJ_WERDLOD.D

Publish date: April 30, 2015

ANALYSIS BY

RonJay Kristoffer Caragay


ALIASES:

PWS:Win32/Zbot (Microsoft); Backdoor.Win32.Androm.ghcb (Kaspersky)

PLATFORM:

Windows

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

  • Threat Type:Trojan

  • Destructiveness:No

  • Encrypted:

  • In the wild: Yes

OVERVIEW

Infection Channel:

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


This online banking Trojan modifies an affected system's proxy settings and adds a malicious root certificate to allow information theft at the network level. These behaviors are seen in malware used in Operation Emmental.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

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 does not have any propagation routine.

It does not have any backdoor routine.

As of this writing, the said sites are inaccessible.

TECHNICAL DETAILS

File Size:

200,297 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

13 Feb 2015

Payload:

Closes windows, Downloads 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.

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
  • %User Temp%\{random filename}.txt ← saves gathered cookies content

(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.. %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 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}.{BLOCKED}6.200.228:8080/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 connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}bunko.org/wp/wp-content/themes/twentyfourteen/images/vrucimeirxeimurixeuri.exe

It saves the files it downloads using the following names:

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

(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.)

As of this writing, the said sites are inaccessible.

NOTES:

This Trojan downloads Windows PoweSshell installer and installs it if the said Windows component is not existing.

It connects to the following to update count hits:

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

It checks for the following processes:

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

It checks for specific list of domains in browser cookies and browser history. When accessing specific domains, users access the malicious SOCKS server using the file from the following:

  • http://{BLOCKED}.{BLOCKED}6.200.228:8080/proxy.pac

The modified prefs.js contains the following:

  • user_pref(network.proxy.type.2)
  • user_pref(network.proxy.autoconfig_url http://{BLOCKED}.{BLOCKED}.200.228:8080/proxy.pac)

It terminates the following processes:

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

It imports rogue root certificates to browsers Internet Explorer and Firefox.

SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.490.02

FIRST VSAPI PATTERN DATE:

20 Feb 2015

VSAPI OPR PATTERN File:

11.491.00

VSAPI OPR PATTERN Date:

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

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://5.196.200.228:8080/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%\cert{value}.der
  • %User Temp%\{random filename}.txt

Step 6

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

Featured Stories

Connect with us on