WORM_PALEVO.ALA
VirTool:Win32/Injector.gen!CA (Microsoft); PWS-Zbot.gen.ajn (McAfee); Trojan.Gen.2 (Symantec); Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It modifies files, disabling programs and applications from properly running. It disables Task Manager, Registry Editor, and Folder Options.
It deletes itself after execution.
TECHNICAL DETAILS
Arrival Details
This worm 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 worm creates the following folders:
- %User Profile%\Application Data\Cazuh
- %User Profile%\Application Data\Amgau
- %User Profile%\Application Data\Neri
(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.)
Other System Modifications
This worm modifies the following files:
- %System%\drivers\etc\hosts
(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.)
It deletes the following files:
- %User Profile%\Application Data\EEB3F8.exe
- %User Profile%\Application Data\EEB3F8.exe:Zone.Identifier
- %User Temp%\1.tmp
(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.. %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 adds the following registry keys:
HKEY_LOCAL_MACHINE\software\microsoft\
windows\currentversion\Policies\
Explorer\Run
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
HKEY_CURRENT_USER\Software\Microsoft\
Xiko
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
65429 = "%User Temp%\msawyg.com"
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Microsoft = "%User Profile%\Application Data\EEB3F8.exe"
Dropping Routine
This worm drops the following files:
- %User Temp%\msawyg.com
- %User Temp%\0000cef8.exe
- %User Temp%\000137a5.exe
- %User Profile%\Cazuh\ytyv.exe
- %User Profile%\Amgau\okfy.ezi
- %User Profile%\Neri\cyga.zap
- %User Profile%\Application Data\EEB3F8.exe
- %System%\drivers\etc\hosts.sys
Other Details
This worm deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
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
Enable Registry Editor, Task Manager, and Folder options
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_LOCAL_MACHINE\software\microsoft\windows\currentversion\Policies\Explorer
- Run
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
- Run
- In HKEY_CURRENT_USER\Software\Microsoft
- Xiko
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\policies\Explorer\Run
- 65429 = "%User Temp%\msawyg.com"
Step 5
Search and delete these files
- %User Temp%\msawyg.com
- %User Temp%\0000cef8.exe
- %User Temp%\000137a5.exe
- %User Profile%\Cazuh\ytyv.exe
- %User Profile%\Amgau\okfy.ezi
- %User Profile%\Neri\cyga.zap
- %User Profile%\Application Data\EEB3F8.exe
- %System%\drivers\etc\hosts.sys
Step 6
Search and delete these folders
- %User Profile%\Application Data\Cazuh
- %User Profile%\Application Data\Amgau
- %User Profile%\Application Data\Neri
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_PALEVO.ALA. 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.
Step 8
Restore deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %System%\drivers\etc\hosts
Step 9
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %User Profile%\Application Data\EEB3F8.exe
- %User Profile%\Application Data\EEB3F8.exe:Zone.Identifier
- %User Temp%\1.tmp
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