WORM_PALEVO.AAL
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This worm attempts to connect to certain URLs. Once a connection is established, it waits for commands from the remote user.
This worm arrives via removable drives. It may be unknowingly downloaded by a user while visiting malicious websites.
It drops copies of itself into all the removable drives connected to an affected system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
Arrival Details
This worm arrives via removable drives.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This worm drops the following copies of itself into the affected system:
- %User Profile%\{random name}.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 injects codes into the following process(es):
- SVCHOST.EXE
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %User Profile%\{random name}.exe
Propagation
This worm drops copies of itself into all the removable drives connected to an affected system.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[autorun]
USEAUTOPLAY=1
shellexecute={random 1}/{random 2}.exe
action=0pen folder to view files using Windows Explorer
ShellfhjfqjfWjflkfjwkl
shell\Explore\command={random 1}/{random 2}.exe
shell\Open\command={random 1}/{random 2}.exe
icon={random 1}/{random 2}.exe
open={random 1}/{random 2}.exe
Backdoor Routine
However, as of this writing, the said sites are inaccessible.
Dropping Routine
This worm sets the attributes of its dropped file(s) to the following:
- Hidden
- System
- Read-Only
Other Details
This worm connects to the following possibly malicious URL:
- {BLOCKED}e.safehousenumber.com
- {BLOCKED}k.portal-protection.net.ru
- {BLOCKED}d.rickstudio.ru
- {BLOCKED}a.cocolands.su
- portal.{BLOCKED}owerbord.com
NOTES:
Once a connection is established, it waits for commands from the remote user which may lead to the following actions:
- Create, Read and Delete Files
- Create/Read/Terminate Processes
- Download other malicious file
- Hijack search queries
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
Scan your computer with your Trend Micro product and note files detected as WORM_PALEVO.AAL
Step 3
Restart in Safe Mode
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 NT\CurrentVersion\Winlogon
- Taskman = %User Profile%\{random name}.exe
- Taskman = %User Profile%\{random name}.exe
Step 5
Search and delete AUTORUN.INF files created by WORM_PALEVO.AAL that contain these strings
USEAUTOPLAY=1
shellexecute={random 1}/{random 2}.exe
action=0pen folder to view files using Windows Explorer
ShellfhjfqjfWjflkfjwkl
shell\Explore\command={random 1}/{random 2}.exe
shell\Open\command={random 1}/{random 2}.exe
icon={random 1}/{random 2}.exe
open={random 1}/{random 2}.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PALEVO.AAL. 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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