WORM_PALEVO.AP
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Propagates via peer-to-peer networks
This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
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
94,208 bytes
EXE
Yes
13 Oct 2010
Connects to URLs/Ips
Arrival Details
This worm arrives via removable drives.
It 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 drops the following copies of itself into the affected system:
- C:\\RECYCLER\\{CLSID}\\syscr.exe
It injects itself into the following processes running in the affected system's memory:
- EXPLORER.EXE
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKLM\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = C:\RECYCLER\{CLSID}\syscr.exe
Propagation
This worm drops copies of itself into the following folders used in peer-to-peer (P2P) networks:
- BearShare
- iMesh
- Shareaza
- Kazaa
- DC++
- eMule
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]
open=RECYCLER\autorun.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\autorun.exe
shell\open\default=1
Download Routine
This worm connects to the following malicious URLs:
- {BLOCKED}lerequests.com
SOLUTION
8.900
7.536.12
13 Oct 2010
10/13/2010 12:00:00 AM
Step 1
Scan your computer with your Trend Micro product and note files detected as WORM_PALEVO.AP
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 HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- Taskman=C:\RECYCLER\{CLSID}\syscr.exe
- Taskman=C:\RECYCLER\{CLSID}\syscr.exe
Step 4
Search and delete AUTORUN.INF files created by WORM_PALEVO.AP that contain these strings
open=RECYCLER\autorun.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\autorun.exe
shell\open\default=1
Step 5
Scan your computer with your Trend Micro product to delete files detected as WORM_PALEVO.AP. 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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