TROJ_DLOADR.ZAI
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Dropped by other malware, 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.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
TECHNICAL DETAILS
22,804 bytes
EXE
Yes
24 Aug 2012
Connects to URLs/IPs, Drops files, Downloads files
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:
- %Application Data%\{Random Charaters}.exe
(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.)
It injects threads into the following normal process(es):
- SVCHOST.EXE
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\Policies\
Explorer\Run
{Random Name} = "%Application Data%\{Random Charaters}.exe"
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- http://{BLOCKED}ucoes.com/media/system/js/xmains.exe
- http://{BLOCKED}ucoes.com/libraries/gigsbda.exe
- http://{BLOCKED}ucoes.com/plugins/editors/88bcae82aa6.exe
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
NOTES:
This Trojan connects to the following site to get the location of the affected machine:
- http://promos.fling.com/geo/txt/city.php
SOLUTION
9.200
9.346.05
24 Aug 2012
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 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\Policies\Explorer\Run
- {Random Name} = "%Application Data%\{Random Charaters}.exe"
- {Random Name} = "%Application Data%\{Random Charaters}.exe"
Step 4
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOADR.ZAI. 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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