TROJ_DROPPR.YYNH
Worm:Win32/Dorkbot.I (Microsoft); ERROR (Kaspersky); Trojan horse BackDoor.Generic17.BJMQ (AVG)
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 deletes itself after execution.
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 copies of itself into the affected system:
- %User Profile%\Application Data\temp.bin
- %User Profile%\Application Data\ScreenSaverPro.scr
- %User Profile%\Microsoft\Jrrarj.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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Screen Saver Pro 3.1 = "%User Profile%\Application Data\ScreenSaverPro.scr"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Jrrarj = "%User Profile%\Microsoft\Jrrarj.exe"
Other System Modifications
This Trojan modifies the following file(s):
- %Windows%\wiadebug.log
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It deletes the following files:
- %User Profile%\Application Data\temp.bin
- %User Profile%\Application Data\ScreenSaverPro.scr
- %User Temp%\apiwipmania.com
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
It adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Recent File List
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Settings
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\View
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Text
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Colors
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\General-Summary
Other Details
This Trojan connects to the following possibly malicious URL:
- http://app.{BLOCKED}ia.net/icon/n.api
- http://api.{BLOCKED}ia.com
- {BLOCKED}0.1
- {BLOCKED}.98.202
It deletes itself after execution.
This report is generated via an automated analysis system.
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
Restart in Safe Mode
Step 3
Delete this registry key
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\Applets
- Paint
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
- Recent File List
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
- Settings
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
- View
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
- Text
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
- Colors
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
- General-Summary
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
- Screen Saver Pro 3.1 = "%User Profile%\Application Data\ScreenSaverPro.scr"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Jrrarj = "%User Profile%\Microsoft\Jrrarj.exe"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DROPPR.YYNH. 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 deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %Windows%\wiadebug.log
Step 7
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.
- %User Profile%\Application Data\temp.bin
- %User Profile%\Application Data\ScreenSaverPro.scr
- %User Temp%\apiwipmania.com
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
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