TROJ_MEDFOS.XM
Trojan:Win32/Tracur.BF (Microsoft)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
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.
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 adds the following folders:
- %Application Data%\Search Settings
- %User Temp%\ns{random}.tmp
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %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.)
It drops and executes the following files:
- %Application Data%\Search Settings\{random}.dll
- %User Temp%\ns{random}.tmp\{random}.dll
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %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.)
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
Search Settings = "Rundll32.exe %Application Data%\Search Settings\{random}.dll,gss_krb5_copy_ccache"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\Search Settings
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Search Settings
{CLSID} = "{Hex Values}"
NOTES:
This trojan monitors the system's browsing activities and may redirect traffic to another URL when one of the following strings are found:
- Yahoo
- Bing
- Aol
- Youtube
- Msn
- Hotmail
- Gmail
- Lavasoft
- Blekko
- Nortonsafe.search.ask.com
- Isearch.avg
- Microsoft.com
- Live.com
This may redirect this traffic to gain money as referrer or to access another malicious URL.
It records browser activies when the following actions are made:
- login
- tweet
- faq
- terms
- conact
- forgotpassword
- signup
- mailto
- playback
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
Scan your computer with your Trend Micro product and note files detected as TROJ_MEDFOS.XM
Step 3
Restart in Safe Mode
Step 4
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
- Search Settings
- Search Settings
Step 5
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
- Search Settings = "Rundll32.exe %Application Data%\Search Settings\{random}.dll,gss_krb5_copy_ccache"
- Search Settings = "Rundll32.exe %Application Data%\Search Settings\{random}.dll,gss_krb5_copy_ccache"
Step 6
Search and delete this folder
- %Application Data%\Search Settings
- %User Temp%\ns{random}.tmp
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_MEDFOS.XM. 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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