WORM_PALEVO.ASB
Trojan.Gen (Symantec); Trojan:Win32/Malagent (Microsoft); Trojan.Win32.Buzus.epzc (Kaspersky); Generic.dx!thl (Mcafee); Trj/Buzus.MN (Panda)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Propagates via removable drives, Spammed via instant messaging applications
This worm may arrive via MSN Messenger.
It does not continue with its routine if the if the malware file name is C:\file.exe or C:\sample.exe or if the user name is CurrentUser.
It is capable of propagating via MSN Messenger by sending messages containing a link where a copy of itself may be downloaded.
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 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.
It opens random ports. It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
111,737 bytes
EXE
Yes
03 Jun 2011
Compromises system security, Sends and receives information
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:
- %User Profile%\Application Data\{random filename}.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 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 = "%User Profile%\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
{garbage characters}
open=sond/Mircr0dll.exe
{garbage characters}
:call
{garbage characters}
icon=%SystemRoot%\system32\SHELL32.dll,4
{garbage characters}
:cmp
{garbage characters}
action=Open folder to view files using Windows Explorer
{garbage characters}
shell\\open\\command=sond/Mircr0dll.exe
{garbage characters}
:jmp5
{garbage characters}
shell\\explore\command=sond/Mircr0dll.exe
{garbage characters}
useautoplay=1
{garbage characters}
Backdoor Routine
This worm opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
It executes the following commands from a remote malicious user:
- Launch TCP or UDP flood
- Download and execute files from the internet
- Visit websites
It connects to the following websites to send and receive information:
- {BLOCKED}i.panadool400.com
- {BLOCKED}i.xylocomod.com
- {BLOCKED}p.xylocomod.com
- {BLOCKED}p.xylocomoda.com
- {BLOCKED}p.xylocomods.com
- www.{BLOCKED}1.com
- www.{BLOCKED}2.com
- www.{BLOCKED}3.com
- www.{BLOCKED}4.com
- www.{BLOCKED}5.com
Other Details
However, as of this writing, the said sites are inaccessible.
NOTES:
It may arrive via MSN Messenger.
It does not continue with its routine if the if the malware file name is C:\file.exe or C:\sample.exe or if the user name is CurrentUser.
It is capable of propagating via MSN Messenger by sending messages containing a link where a copy of itself may be downloaded.
SOLUTION
8.900
8.200.10
03 Jun 2011
8.201.00
03 Jun 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.ASB 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\Microsoft\Windows NT\CurrentVersion\Winlogon
- Taskman = "%User Profile%\Application Data\{random filename}.exe"
- Taskman = "%User Profile%\Application Data\{random filename}.exe"
Step 4
Search and delete AUTORUN.INF files created by WORM_PALEVO.ASB that contain these strings
Step 5
Search and delete files detected as WORM_PALEVO.ASB
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_PALEVO.ASB. 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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