TROJ_REFPRON.JB
Trojan:Win32/Refpron.gen!A (Microsoft), Trojan Horse (Symantec), Trj/Downloader.MDW (Panda), W32/Downldr2.EJUQ (FProt), Mal/Generic-L (Sophos)
Windows 2000, Windows XP, Windows Server 2003, Windows Vista, Windows 7
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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.
TECHNICAL DETAILS
186,880 bytes
EXE
No
17 Oct 2012
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:
- %System%\comsa32.sys - a text file that contains the ID number of the malware
- %User Temp%\mta{random 5-digit number}.dll - copy of the legitimate file URLMON.DLL
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %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.)
Autostart Technique
This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding
ImagePath = "{Malware Path and File Name}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding
Type = "10"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding
DisplayName = "AFinding"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding
ObjectName = "Local System"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding\Security
Security = "{random values}"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AFinding\Security
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM
BuildW = "PlAdkM3dDgnvV+L"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM
_{first 2 characters of the malware's file name} = "{random value}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM
ud{random 2 characters} = "{encrypted location of mta{random 5-digit number}.dll}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM
m{random 2 characters} = "{random value}"
Other Details
This Trojan requires the following additional components to properly run:
- %System%\drmgs.sys
- rtl60.bpl - Borland Delphi Library file
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
NOTES:
It attempts to open the file %System%\drmgs.sys.
It uses the following command line parameters:
- /Uninstall
- start
- /Install
SOLUTION
9.300
9.472.07
20 Oct 2012
9.473.00
21 Oct 2012
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Scan your computer with your Trend Micro product and note files detected as TROJ_REFPRON.JB
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_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM
- BuildW = "PlAdkM3dDgnvV+L"
- BuildW = "PlAdkM3dDgnvV+L"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM
- _{first 2 characters of the malware's file name} = "{random value}"
- _{first 2 characters of the malware's file name} = "{random value}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM
- ud{random 2 characters} = "{encrypted location of mta{random 5-digit number}.dll}"
- ud{random 2 characters} = "{encrypted location of mta{random 5-digit number}.dll}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM
- m{random 2 characters} = "{random value}"
- m{random 2 characters} = "{random value}"
Step 5
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- AFinding
- AFinding
Step 6
Search and delete the file detected as TROJ_REFPRON.JB
Step 7
Search and delete these files
- %System%\comsa32.sys
- %User Temp%\mta{random 5-digit number}.dll
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_REFPRON.JB. 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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