TROJ_OFICLA.AMF
Trojan:Win32/Oficla.AH (Microsoft), PWS-Zbot.gen.ab (McAfee) ,
Windows 2000, XP, Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It resolves a Domain Naming System (DNS) host name or Internet Protocol (IP) address.
TECHNICAL DETAILS
Varies
PE
UPX
Yes
12 Nov 2010
Arrival Details
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
Installation
This Trojan drops the following copies of itself into the affected system:
- %User Profile%\Application Data\{random name}\csrss.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It creates the following folders:
- %User Profile%\Application Data\{random name}
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Autostart Technique
This Trojan modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = explorer.exe %User Profile%\Application Data\{random name}\csrss.exe
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This Trojan adds the following line(s)/entry(ies) in the WIN.INI file:
- [random characters_1]
- {random characters_2 = random characters_3}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft
setiasworld = {data}
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and file name}.exe = {malware path and file name}.exe:*:Enabled:ldrsoft
Other Details
This Trojan resolves a Domain Naming System (DNS) host name or Internet Protocol (IP) address.
SOLUTION
8.900
7.616.12
12 Nov 2010
7.613.00
12 Nov 2010
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
Scan your computer with your Trend Micro product and note files detected as TROJ_OFICLA.AMF
Step 3
Restart in Safe Mode
Step 4
Restore this modified 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 NT\CurrentVersion\Winlogon
- From: Shell = explorer.exe %User Profile%\Application Data\{random name}\csrss.exe
To: Shell = Explorer.exe
- From: Shell = explorer.exe %User Profile%\Application Data\{random name}\csrss.exe
Step 5
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
- setiasworld = {data}
- setiasworld = {data}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- {malware path and file name}.exe = {malware path and file name}.exe:*:Enabled:ldrsoft
- {malware path and file name}.exe = {malware path and file name}.exe:*:Enabled:ldrsoft
Step 6
Search and delete these folders
Step 7
Remove the following string/s that this malware/grayware added to these system configuration files
[random characters_1]
{random characters_2 = random characters_3}
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_OFICLA.AMF. 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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