WORM_PALEVO.MBC
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Propagates via flashdrives, Propagates via instant messaging applications
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 executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
238,080 bytes
EXE
Yes
04 Oct 2011
Drops files, Connects to URLs/IPs, Compromises system security
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:
- %Application Data%\ydze.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%\ydze.exe"
Propagation
This worm creates the following folders in all removable drives:
- Sex.and.the.City.2
It drops the following copy(ies) of itself in all removable drives:
- {Drive:}\Sex.and.the.City.2\Sex.and.the.City.2.R5.Xvid-TPB.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=Sex.and.the.City.2//////Sex.and.the.City.2.R5.Xvid-TPB.exe
;{Garbage Characters}
USEAuTopLAY=1
;{Garbage Characters}
SHELL\\\EXplore\\COMMAND=Sex.and.the.City.2////\Sex.and.the.City.2.R5.Xvid-TPB.exe
;{Garbage Characters}
SHELL\\\OPEN\\COMMAND=Sex.and.the.City.2////\Sex.and.the.City.2.R5.Xvid-TPB.exe
;{Garbage Characters}
It sends copies of itself to target recipients using the following instant-messaging (IM) applications:
- MSN Messenger
Backdoor Routine
This worm executes the following commands from a remote malicious user:
- Display advertisements
- Performs Slowloris, UDP and TCP Flooding method
- Download files
- Start and stop MSN spreader
- Start and stop reverse socks and reverse connect to IP and PORT
- Start and stop USB spreader
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}ize.com
- {BLOCKED}rystorm.net
- {BLOCKED}bam.info
- {BLOCKED}dcast.com
- {BLOCKED}ucks.com
SOLUTION
9.200
8.472.03
04 Oct 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.MBC using the 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 = "%Application Data%\ydze.exe"
- Taskman = "%Application Data%\ydze.exe"
Step 4
Search and delete AUTORUN.INF files created by WORM_PALEVO.MBC that contain these strings
Step 5
Search and delete these folders
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_PALEVO.MBC. 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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