TROJ_AGENT.AWNT
Windows 98, ME, NT, 2000, XP, Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type:
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan adds registry entries to enable its automatic execution at every system startup.
It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.
TECHNICAL DETAILS
38912 bytes
Yes
17 Dec 2009
Installation
This Trojan drops the following files:
- %System%\nso12k.sys
- %User Temp%\UAC42b4.tmp
(Note: %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.. %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.)
It drops the following copies of itself into the affected system:
HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\Run\upbb
%System%\bb.exe- %System%\cssrss.exe
(Note: %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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
Download Routine
This Trojan connects to the following malicious URLs:
- {BLOCKED}
- {BLOCKED}
SOLUTION
Step 1
Terminate the malware/grayware/spyware process:
Step 2
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.
- HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\Run\WMDM PMSP Service
- %System%\cssrss.exe=REG_SZ
Step 3
Search and delete these files
- %System%\nso12k.sys
- %System%\cssrss.exe
Note: To do a search for the following files, right-click Start then click Search... or Find..., depending on the version of Windows you are running. For each file to be deleted, type its file name in the Named input box. In the Look In drop-down list, select My Computer, then press Enter.
Step 4
Scan your computer with your Trend Micro product to delete files detected as
TROJ_AGENT.AWNT
*Note: 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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