TROJ_DROPPER.LEX
TrojanDownloader:Win32/Waledac.C (Microsoft); FakeAlert-AntiVirusPro (McAfee); Trojan.Gen (Symantec); Trojan-Dropper.Win32.Daws.aeue (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
TECHNICAL DETAILS
44,545 bytes
EXE
Yes
05 Mar 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.
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
MozillaAgent = "%Temp%\_ex-68.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\Mozilla
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Mozilla
AppID = "DH/hNYp2eKgbvOhuuCQ7JArRw+4/Zya1bNjupUiLYYiqKnMRDluggORaG6BpLUVGpw=="
HKEY_CURRENT_USER\Software\Mozilla
ID = "5"
HKEY_CURRENT_USER\Software\Mozilla
ID2 = "{random values}"
HKEY_CURRENT_USER\Software\Mozilla
ID3 = "{random values}"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Tcpip\Parameters\
Interfaces\{6D128ACA-CE90-4D8D-B04F-CD01DBA59CE2}
NameServer = "8.8.8.8,8.8.8.8,8.8.4.4"
Dropping Routine
This Trojan drops the following files:
- %Temp%\_ex-68.exe
- %Temp%\_ex-08.exe
- %System%\Packet.dll
- %System%\wpcap.dll
- %System%\drivers\npf.sys
(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.. %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.)
This report is generated via an automated analysis system.
SOLUTION
9.200
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
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
- Mozilla
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\Windows\CurrentVersion\Run
- MozillaAgent = "%Temp%\_ex-68.exe"
- In HKEY_CURRENT_USER\Software\Mozilla
- AppID = "DH/hNYp2eKgbvOhuuCQ7JArRw+4/Zya1bNjupUiLYYiqKnMRDluggORaG6BpLUVGpw=="
- In HKEY_CURRENT_USER\Software\Mozilla
- ID = "5"
- In HKEY_CURRENT_USER\Software\Mozilla
- ID2 = "{random values}"
- In HKEY_CURRENT_USER\Software\Mozilla
- ID3 = "{random values}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Interfaces\{6D128ACA-CE90-4D8D-B04F-CD01DBA59CE2}
- NameServer = "8.8.8.8,8.8.8.8,8.8.4.4"
Step 5
Search and delete these files
- %Temp%\_ex-68.exe
- %Temp%\_ex-08.exe
- %System%\Packet.dll
- %System%\wpcap.dll
- %System%\drivers\npf.sys
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DROPPER.LEX. 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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