WORM_PALEVO.TNY
W32.Pilleuz!gen15 (Symantec); Trojan:Win32/Rimecud.A (Microsoft); Trojan.Win32.Pincav.atfx (Kaspersky); Generic Dropper.yb (Mcafee); Mal/Palevo-A (Sophos)
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This worm sends and receives commands from a remote user, thus compromises system security.
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 adds registry entries to enable its automatic execution at every system startup.
It drops copies of itself in all removable drives. 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
100,864 bytes
EXE
Yes
04 Apr 2011
Compromises system security
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 drops the following copies of itself into the affected system:
- %Application Data%\{random filename}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
It injects itself into the following processes as part of its memory residency routine:
- explorer.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 = "%Application Data%\{random filename}.exe"
Propagation
This worm drops copies of itself in all removable drives.
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]
shell\Install\command=POPULAR\prezidente.exe
shell\open\command=POPULAR\prezidente.exe
shell\explore\command=POPULAR\prezidente.exe
Shell\open\command=POPULAR\prezidente.exe
useautoplay=1
shellexecute=POPULAR\prezidente.exe
open=POPULAR\prezidente.exe
action=Open folder to view files
icon=shell32.dll,4
Backdoor Routine
This worm connects to the following URL(s) to send and receive commands from a remote malicious user:
- jebena.{BLOCKED}olic.su
- peer.{BLOCKED}losarske.ru
- teske.{BLOCKED}arke.com
- juice.{BLOCKED}racala.org
- {BLOCKED}.190.237
SOLUTION
8.900
7.952.01
04 Apr 2011
Step 1
For Windows ME and XP 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.TNY
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 = "%Application Data%\{random filename}.exe"
- Taskman = "%Application Data%\{random filename}.exe"
Step 5
Search and delete AUTORUN.INF files created by WORM_PALEVO.TNY that contain these strings
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PALEVO.TNY 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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