Analysis by: John Donnie Celestre
ALIASES:

TrojanDownloader:JS/Nemucod (MICROSOFT); Trojan-Downloader.JS.Nemucod (IKARUS)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Worm 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: 16,223 bytes
File Type: JS
Memory Resident: Yes
Initial Samples Received Date: 26 Dec 2018

Arrival Details

This Worm 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 Worm drops the following file(s)/component(s):

  • %User Temp%\{malware filename}.js
  • %AppDataLocal%\{randomly generated chars}
  • %AppDataLocal%\{randomly generated chars}\{random chars}
  • %AppDataLocal%\{randomly generated chars}\{random chars}.js
  • %AppDataLocal%\{randomly generated chars}\{random chars}.exe
  • {Removable}:\Files\{num}\{malware copy}.js
  • {Removable}:\Files.bat
  • {Removable}:\System Volume Information\{random}\{random}

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista, 7, and 8.)

It adds the following processes:

  • "%System%\wscript.exe" "%User Temp%\{malware filename}.js" {randomly generated parameter}
  • "%System%\cmd.exe" /c del /F /S /Q "%AppDataLocal%\{randomly generated chars}\*.exe"
  • "%AppDataLocal%\{randomly generated chars}\{random chars}.exe" "%User Temp%\{malware filename}.js" {randomly generated parameter}
  • %System%\cmd.exe /c shutdown /p /f

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista, 7, and 8.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = %AppData%\{random}\{random}.exe "%AppData%\{random}\{random}.js"

It drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\Start.lnk
  • %User Startup%\Start.lnk

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. . %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Propagation

This Worm creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Process Termination

This Worm terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • "autoruns"
  • "avast"
  • "avenger"
  • "avg"
  • "ccsetup"
  • "cleaner"
  • "combofix"
  • "dds"
  • "emergencykit"
  • "fiddler"
  • "filemon"
  • "frst"
  • "fs20"
  • "fss"
  • "gmer"
  • "hijackthis"
  • "hotfix"
  • "housecall"
  • "issetup"
  • "klwk"
  • "mbam"
  • "mbsa"
  • "mcshield"
  • "mrt"
  • "msconfig"
  • "msss"
  • "otl"
  • "perfmon"
  • "procexp"
  • "procmon"
  • "ptinstall"
  • "regedit"
  • "regmon"
  • "resmon"
  • "roguekiller"
  • "rstrui"
  • "rubotted"
  • "sdasetup"
  • "sysclean"
  • "tcpview"
  • "unlocker"
  • "vbsvbe"
  • "windows-kb"
  • "wireshark"
  • "zoek"
  • "zphdiag"

Other Details

This Worm connects to the following URL(s) to check for an Internet connection:

  • http://www.microsoft.com/
  • http://www.google.com/
  • http://www.bing.com/

It connects to the following possibly malicious URL:

  • http://{BLOCKED}it.com/0.html
  • http://{BLOCKED}ille.com/0.html
  • http://{BLOCKED}ille.com/2.html

It does the following:

  • Turns the following into lnk files pointing to a malware copy whose extension contains in removable drives:
    • "avi"
    • "doc"
    • "docx"
    • "exe"
    • "flv"
    • "gif"
    • "jpeg"
    • "jpg"
    • "m4a"
    • "mov"
    • "mp3"
    • "mp4"
    • "mpeg"
    • "mpg"
    • "ogg"
    • "pdf"
    • "png"
    • "rtf"
    • "txt"
    • "wav"
    • "webm"
    • "wma"
    • "wmv"
  • Filenames for autostart could be any of the following:
    • Windows Explorer.lnk
    • empezar.lnk
    • atajo.lnk
    • Start.lnk
    found in the following paths:
    • \ProgramData\Microsoft\Windows\Start Menu\Programs\Startup\
    • \AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\
    • \Start Menu\Programs\Startup\

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.714.08
FIRST VSAPI PATTERN DATE: 27 Dec 2018
VSAPI OPR PATTERN File: 14.715.00
VSAPI OPR PATTERN Date: 28 Dec 2018

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

Restart in Safe Mode

[ Learn More ]

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\Run
    • {random} = %AppData%\{random}\{random}.exe "%AppData%\{random}\{random}.js"

Step 5

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

Step 6

Set system to display all hidden files and folders

[ Learn More ]

Step 7

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.
  • %User Temp%\{malware filename}.js
  • %AppDataLocal%\{randomly generated chars}
  • %AppDataLocal%\{randomly generated chars}\{random chars}
  • %AppDataLocal%\{randomly generated chars}\{random chars}.js
  • %AppDataLocal%\{randomly generated chars}\{random chars}.exe
  • {Removable}:\Files\{num}\{malware copy}.js
  • {Removable}:\Files.bat
  • {Removable}:\System Volume Information\{random}\{random}
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\Start.lnk
  • %User Startup%\Start.lnk

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.JS.BONDAT.DNN. 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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