WORM_PALEVO.ANL
W32/Worm-FDK!3466B5875815 (McAfee), W32/Palevo.MATH!worm (Fortinet)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives by connecting affected removable drives to a system. 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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
TECHNICAL DETAILS
Arrival Details
This worm arrives by connecting affected removable drives to a system.
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:
- %User Profile%\celp.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
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%\celp.exe"
Propagation
This worm creates the following folders in all removable drives:
- {drive letter}\rejekto
It drops the following copy(ies) of itself in all removable drives:
- {drive letter}\rejekto\perfero.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:
[autorun]
{garbage}
shell\\Open\\command=rejekto\perfero.exe
{garbage}
action=Open folder to view files using Windows Explorer
{garbage}
Shell\\open\\command=rejekto\perfero.exe
{garbage}
shellexecute=rejekto\perfero.exe
{garbage}
shell\\explore\\command=rejekto\perfero.exe
{garbage}
icon=SHELL32.dll,4
{garbage}
open=rejekto\perfero.exe
{garbage}
USEAUTOPLAY=1
{garbage}
Download Routine
This worm accesses the following websites to download files:
- http://{BLOCKED}.{BLOCKED}.53.36/zibar/{random number}.exe
It saves the files it downloads using the following names:
- %User Temp%\{random number}.exe
(Note: %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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Scan your computer with your Trend Micro product and note files detected as WORM_PALEVO.ANL
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%\celp.exe"
- Taskman = "%User Profile%\celp.exe"
Step 5
Search and delete AUTORUN.INF files created by WORM_PALEVO.ANL that contain these strings
Step 6
Search and delete the files detected as WORM_PALEVO.ANL
*Note: Some component files may be hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
To stop the malware/grayware from running when certain files are opened:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the Named input box, type the name of the file that was detected earlier.
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
For Windows Vista and Windows 7:
- Click Start>Computer.
- In the Search Computer input box, type the name of the file detected earlier, and press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 7
Search and delete these folders
- {drive letter}\rejekto
Step 8
Search and delete this file
- %User Temp%\{random number}.exe
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PALEVO.ANL. 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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