WORM_PALEVO.CU
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. It may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
TECHNICAL DETAILS
243,200 bytes
PE
Yes
09 Feb 2011
Arrival Details
This worm arrives via removable drives.
It may be downloaded by other malware/grayware/spyware from remote sites.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This worm drops the following file(s)/component(s):
- {drive letter}:\garbage\Desktop.ini
- %System Root%\RECYCLER\{SID}\Desktop.ini
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It drops the following copies of itself into the affected system:
- %System Root%\RECYCLER\{SID}\winsystem.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It injects itself into the following processes running in the affected system's memory:
- Explorer.exe
It creates the following folders:
- %System Root%\RECYCLER\{SID}
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Mircosoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %System Root%\RECYCLER\{SID}\winsystem.exe
Propagation
This worm creates the following folders in all removable drives:
- {drive letter}:\garbage
It drops the following copy(ies) of itself in all removable drives:
- {drive letter}:\garbage\pizdec.exe
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:
;{garbage characters}
[AutoRun]
;{garbage characters}
open=.\garbage/pizdec.exe
;{garbage characters}
icon = %System Root%\system32\SHELL32.dll,4
;{garbage characters}
action=Open folder to view files using Windows Explorer
;{garbage characters}
useauTOplay=1
;{garbage characters}
shell\\open\\command=garbage\\pizdec.exe
;{garbage characters}
shell\\explore\\command=garbage////pizdec.exe
;{garbage characters}
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
NOTES:
Other Details
Based on analysis of the codes, it has the following capabilities:
Spreads via MSN Messenger and through the following peer-to-peer (P2P) applications:
- Ares
- BearShare
- DC++
- eMule
- iMesh
- Kazaa
- LimeWire
- Shareaza
Performs a denial of service (DoS) attacks on infected systems using SYN flooding
SOLUTION
8.900
7.826.09
09 Feb 2011
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
Identify and delete files detected as WORM_PALEVO.CU using either the Startup Disk or Recovery Console
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 HKEY_LOCAL_MACHINE\SOFTWARE\Mircosoft\Windows NT\CurrentVersion\Winlogon
- Taskman = %System Root%\RECYCLER\{SID}\winsystem.exe
Step 4
Search and delete this folder
- {drive letter}:\garbage
- %System Root%\RECYCLER\{SID}
Step 5
Search and delete AUTORUN.INF files created by WORM_PALEVO.CU that contain these strings
;{garbage characters}
[AutoRun]
;{garbage characters}
open=.\garbage/pizdec.exe
;{garbage characters}
icon = %System Root%\system32\SHELL32.dll,4
;{garbage characters}
action=Open folder to view files using Windows Explorer
;{garbage characters}
useauTOplay=1
;{garbage characters}
shell\\open\\command=garbage\\pizdec.exe
;{garbage characters}
shell\\explore\\command=garbage////pizdec.exe
;{garbage characters}
Step 6
Scan your computer with your Trend Micro product to clean files detected as WORM_PALEVO.CU. 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.
Did this description help? Tell us how we did.