TROJ_LERSPENG.A
TrojanDownloader:Win32/Lerspeng.B (Microsoft), Trojan.Win32.Badur.hvwx (Kaspersky), Trojan.Badur! (Agnitum), Trojan.Win32.Badur.Ar (Baidu-International), TrojanDownloader.Lerspeng.r4 (CAT-QuickHeal), Win32/TrojanDownloader.Small.PSD (ESET-NOD32)
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:
In the wild: Yes
OVERVIEW
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It 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 as an attachment to email messages spammed by other malware/grayware or malicious users.
It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CLASSES_ROOT\.max
HKEY_CLASSES_ROOT\.max\ShellNew
HKEY_CLASSES_ROOT\Matrix.Document
HKEY_CLASSES_ROOT\Matrix.Document\DefaultIcon
HKEY_CLASSES_ROOT\Matrix.Document\shell
HKEY_CLASSES_ROOT\Matrix.Document\shell\
open
HKEY_CLASSES_ROOT\Matrix.Document\shell\
open\command
HKEY_CLASSES_ROOT\Matrix.Document\shell\
print
HKEY_CLASSES_ROOT\Matrix.Document\shell\
print\command
HKEY_CLASSES_ROOT\Matrix.Document\shell\
printto
HKEY_CLASSES_ROOT\Matrix.Document\shell\
printto\command
HKEY_CURRENT_USER\Software\Matrix
HKEY_CURRENT_USER\Software\Matrix\
Recent File List
HKEY_CURRENT_USER\Software\Matrix\
Settings
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.max
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.max\ShellNew
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\DefaultIcon
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\open
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\open\
command
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\print
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\print\
command
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\printto
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\printto\
command
It adds the following registry entries:
HKEY_CLASSES_ROOT\.max
Default = "Matrix.Document"
HKEY_CLASSES_ROOT\.max\ShellNew
NullFile = ""
HKEY_CLASSES_ROOT\Matrix.Document
Default = "Matrix Document"
HKEY_CLASSES_ROOT\Matrix.Document\DefaultIcon
Default = "{malware path}\{malware filename}.exe,0"
HKEY_CLASSES_ROOT\Matrix.Document\shell\
open\command
Default = "{malware path}\{malware filename}.exe"%1""
HKEY_CLASSES_ROOT\Matrix.Document\shell\
print\command
Default = "{malware path}\{malware filename}.exe /p"%1""
HKEY_CLASSES_ROOT\Matrix.Document\shell\
printto\command
Default = "{malware path}\{malware filename}.exe /pt"%1""%2""%3""%4""
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.max
Default = "Matrix.Document"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.max\ShellNew
NullFile = ""
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document
Default = "Matrix Document"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\DefaultIcon
Default = "{malware path}\{malware filename}.exe,0"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\open\
command
Default = "{malware path}\{malware filename}.exe"%1""
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\print\
command
Default = "{malware path}\{malware filename}.exe /p"%1""
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Matrix.Document\shell\printto\
command
Default = "{malware path}\{malware filename}.exe /pt"%1""%2""%3""%4""
Download Routine
This Trojan saves the files it downloads using the following names:
- %User Temp%\mss{random}.exe
(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.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}oteles.pt/111
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_CLASSES_ROOT
- .max
- .max
- In HKEY_CLASSES_ROOT
- Matrix.Document
- Matrix.Document
- In HKEY_CURRENT_USER\Software
- Matrix
- Matrix
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
- .max
- .max
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
- Matrix.Document
- Matrix.Document
Step 4
Search and delete these files
- %User Temp%\mss{random}.exe
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_LERSPENG.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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