Analysis by: RonJay Kristoffer Caragay

 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

This Trojan arrives as attachment to mass-mailed email messages.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 254,452 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 Aug 2015
Payload: Closes windows, Downloads files

Arrival Details

This Trojan arrives as attachment to mass-mailed email messages.

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.)

Autostart Technique

This Trojan drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\system.pif → copy of itself

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

This Trojan modifies the following file(s):

  • {firefox path}\prefs.js
    This modified 'prefs.js' contains the following:
    • user_pref("network.proxy.type", 2)
    • user_pref("network.proxy.autoconfig_url", "https://{BLOCKED}evpnalarm.net/securevpn.js")

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
AutoConfigURL = "https://{BLOCKED}evpnalarm.net/securevpn.js"

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}omla.{BLOCKED}uhi.at/vs28/schule/administrator/components/com_phocagallery/c.exe
  • http://{BLOCKED}tsu-{BLOCKED}et.co.jp/images/medical/rttcrvtretrgyrtytvucyruycutyftr/erzewerebytvtcytr.exe

It saves the files it downloads using the following names:

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

(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.

Other Details

This Trojan does the following:

  • It downloads and install the following Microsoft Windows Tools if not existing:
    • Microsoft Windows PowerShell
    • Microsoft .Net Framework
    • Windows Server Administration Tools
  • It access the following legitimate URLs to download these installers:
    • http://download.microsoft.com/download/{values}/{GUID}/dotnetfx35setup.exe
    • http://download.microsoft.com/download/{values}/{GUID}/WindowsXP-KB926139-v2-x86-ENU.exe
    • http://download.microsoft.com/download/{values}/{GUID}/adminpak.exe
  • It connects to the following to update count hits:
    • https://www.{BLOCKED}unter.com/counter.php?mvtyiortiyoxirt
    • https://www.{BLOCKED}unter.com/counter.php?yitoyctoyxirnymrxoii
  • It checks for the following processes:
    • VBoxService.exe
    • VBoxTray.exe
    • Proxifier.exe
    • prl_cc.exe
    • prl_tools.exe
    • vmusrvc.exe
    • vmsrvc.exe
    • vmtoolsd.exe
  • It checks for social media and bank related domains on cookies and history
  • When accessing specific domains, users access the malicious SOCKS server using the file from the following:
    • https://{BLOCKED}evpnalarm.net/securevpn.js
  • It terminates the following processes:
    • chrome.exe
    • firefox.exe
    • iexplore.exe
  • It imports rogue root certificates to browsers (Internet Explorer, Firefox).

  SOLUTION

Minimum Scan Engine: 9.750

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

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 = "https://alarmtonnel.com/akamaijp.js"

Step 4

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

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_WERDLOD.T. 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 6

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


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