TROJ_DOWNEKS.B
Trojan-Downloader.Win32.Downeks.c (Kaspersky); Trojan.Downeks (NORTON); Troj/DwnLdr-RLP (Sophos_Lite)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
It steals certain information from the system and/or the user.
It connects to certain websites to send and receive information.
TECHNICAL DETAILS
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 files:
- %Application Data%\{random numbers}
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)
It drops and executes the following files:
- %User Temp%\Readme.exe
- %User Temp%\fasad.doc
(Note: %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.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- qrr5flTFdYVLNlAuK5Xvmuynxf1a9rMY
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
Software\Microsoft\Windows\
CurrentVersion\Run
Download Excute = %Application Data%\Download Excute.exe
It drops the following file(s) in the Windows Startup folder to enable its automatic execution at every system startup:
- Readme.lnk
Download Routine
This Trojan saves the files it downloads using the following names:
- %Application Data%\Download Excute.exe
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
Information Theft
This Trojan steals the following information:
- Computer Name
- User Name
- Volume Serial Number of Drive C:
- Operating System version
- Installed .NET Framework versions
- Processor Type
- Screenshots
- Security products installed on Program Files
Other Details
This Trojan connects to the following URL(s) to get the affected system's IP address:
- http://myexternalip.com/raw
It connects to the following website to send and receive information:
- dl.{BLOCKED}se.com
It does the following:
- It checks if the following strings match the username:
- abc
- Admin or admin
- antonie
- antonis
- Antony
- Babbage
- BUF
- David
- GT
- John
- Johnson
- Klone
- laptop1
- luser
- Miller
- mini
- Owner
- PetMay
- Public
- Rivest
- support
- susan
- swt_000
- SYSTEM
- test
- User or user
- Wilbert
- worker
- It checks for the existence of directories in Program Files with the following strings:
- avira
- avast
- avg
- eset
- kaspersky
- alwil
- onecare
- security
- mcafee
- symantec
- norton
- defender
- bitdefender
- It displays a message box with a message as defined by the server.
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
Restart in Safe Mode
Step 4
Delete this registry value
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
- Download Excute = %Application Data%\Download Excute.exe
- Download Excute = %Application Data%\Download Excute.exe
Step 5
Search and delete this file
- %Application Data%\{random numbers}
- %Application Data%\Download Excute.exe
- %User Temp%\Readme.exe
- %User Temp%\fasad.doc
- %Startup%\Readme.lnk
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DOWNEKS.B. 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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