TROJ_HDROP.A
Trojan.Mdropper (Symantec)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Trojan
Destructiveness: No
Encrypted: No
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.
However, as of this writing, the said sites are inaccessible.
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:
- %User Temp%\HwpLib.dll - detected as TSPY_GRABBER.A
(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 and 7.)
Download Routine
This Trojan accesses the following websites to download files:
- http://ts-c.{BLOCKED}a.ne.jp:80/mt/php/0.css
- http://{BLOCKED}f.net:80/mt/php/0.css
- http://{BLOCKED}ya.co.kr:80/bbs/imgFd/0.css
- http://milk-cb.{BLOCKED}a.ne.jp:80/menu/0.css
It saves the files it downloads using the following names:
- {common path of Hanggul Word Processor}\0.css
- such as %System Root%\HNC\Hwp70\0.css
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Information Theft
This Trojan gathers the following data:
- Processor Information
- List of documents (.hwp, .doc, .docx, .xls, .xlsx)
- List of running services
- IP configuration
- Environment Variable values
- ALLUSERSPROFILE
- APPDATA
- CLIENTNAME
- CommonProgramFiles
- COMPUTERNAME
- ComSpec
- FP_NO_HOST_CHECK
- HOMEDRIVE
- HOMEPATH
- J2D_D3D
- LOGONSERVER
- NUMBER_OF_PROCESSOR
- OS
- Path
- PATHEXT
- PROCESSOR_ARCHITECT
- PROCESSOR_IDENTIFIE
- PROCESSOR_LEVEL
- PROCESSOR_REVISION
- ProgramFiles
- PROMPT
- SESSIONNAME
- SystemDrive
- SystemRoot
- TEMP
- TMP
- USERDOMAIN
- USERNAME
- USERPROFILE
- windir
Stolen Information
This Trojan saves the stolen information in the following file:
- {common path of Hanggul Word Processor}\{random characters}.gif
- such as %System Root%\HNC\Hwp70\{random characters}.gif
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It sends the gathered information via HTTP POST to the following URL:
- http://ts-c.{BLOCKED}a.ne.jp:80/mt/php/mt2.php
- http://{BLOCKED}f.net:80/mt/php/lib/function.mbbstring.php
- http://{BLOCKED}ya.co.kr:80/bbs/imgFd/m1.php
- http://milk-cb.{BLOCKED}a.ne.jp:80/menu/a_9.php
Other Details
However, as of this writing, the said sites are inaccessible.
NOTES:
This Trojan gathers information by executing commands through cmd.exe.
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
Remove grayware/spyware files dropped/downloaded by TROJ_HDROP.A
- TSPY_GRABBER.A
Step 3
Search and delete these files
- {common path of Hanggul Word Processor}\0.css
- {common path of Hanggul Word Processor}\0.gif
Step 4
Scan your computer with your Trend Micro product to delete files detected as TROJ_HDROP.A. 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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