BKDR_AGENT.AVGS
TrojanDownloader:Win32/VB.LN (Microsoft); Generic VB.i (McAfee); Backdoor.Trojan (Symantec); Backdoor.Win32.Agent.arso (Kaspersky); Trojan.Win32.VBDldr.b (v) (Sunbelt); Gen:Trojan.Heur.ZDR.2 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor 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
128,401 bytes
EXE
Yes
24 Apr 2012
Arrival Details
This backdoor 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 backdoor creates the following folders:
- %Program Files%\Wintows Publtnx
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
windt32_ttnx = "%Program Files%\Wintows Publtnx\services.exe"
Dropping Routine
This backdoor drops the following files:
- %System Root%\4\17\2012.txt
- %System%\2.txt
- %System Root%\1.reg
- %User Profile%\????????\winv32_tlcc.vbs
- %User Startup%\winv32_tlcc.vbs
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %System% is the Windows system folder, which is usually C:\Windows\System32.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
This report is generated via an automated analysis system.
SOLUTION
9.200
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- windt32_ttnx = "%Program Files%\Wintows Publtnx\services.exe"
Step 4
Search and delete these components
- %System Root%\4\17\2012.txt
- %System%\2.txt
- %System Root%\1.reg
- %User Profile%\????????\winv32_tlcc.vbs
- %User Startup%\winv32_tlcc.vbs
Step 5
Search and delete this folder
- %Program Files%\Wintows Publtnx
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_AGENT.AVGS. 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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