Analysis by: Jaime Benigno Reyes
ALIASES:

Net-Worm.Win32.Kolab.dwx (Kaspersky); W32.Spybot.Worm (Symantec)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet, Via removable drives, Propagates via software vulnerabilities

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 opens certain ports to access shared networks. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system. It takes advantage of software vulnerabilities to propagate across networks.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 81,920 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 02 Sep 2014
Payload: Compromises system security, Drops files

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 and executes them:

  • %Windows%\system\lsass.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It drops the following component file(s):

  • %System%\drivers\sysdrv32.sys - detected as RTKT_TCPAGENT.W

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • x3Ddfqjif9ij3re238KASx

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
ilass = "%Windows%\system\lsass.exe"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
Start = "3"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
ImagePath = "\??\%System%\drivers\sysdrv32.sys"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
DisplayName = "Play Port I/O Driver"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
Group = "SST wanport drivers"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal\
lsass
(Default) = "Service"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network\
lsass
(Default) = "Service"

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal\
lsass

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network\
lsass

Propagation

This worm opens the following ports to access shared networks:

  • 445

It drops the following copy(ies) of itself in all removable drives:

  • {Removable Drive Letter}:\KEY-INSTALLER.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]
shellexecute=Key-Installer.exe
action=Open folder to view files
shell\default=Open
shell\default\command=Key-Installer.exe
shell=default

It takes advantage of the following software vulnerabilities to propagate across networks:

Backdoor Routine

This worm executes the following commands from a remote malicious user:

  • download and execute arbitrary files
  • run or terminate applications
  • perform remote shell commands

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • 1.{BLOCKED}ww.com

However, as of this writing, the said sites are inaccessible.

Other Details

This worm deletes the initially executed copy of itself

NOTES:
It generates randomly generated IP address then attempts to establish a connection using TCP port 445. Once a successful connection is established, it then sends specially crafted RPC request along with a copy of itself.

It does not have rootkit capabilities.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.126.05
FIRST VSAPI PATTERN DATE: 04 Sep 2014
VSAPI OPR PATTERN File: 11.127.00
VSAPI OPR PATTERN Date: 04 Sep 2014

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove malware/grayware files dropped/downloaded by WORM_PALEVO.JB. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • RTKT_TCPAGENT.W

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry key

[ Learn More ]

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Minimal
    • lsass
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network
    • lsass
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services
    • sysdrv32

Step 6

Delete this registry value

[ Learn More ]

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\CurrentVersion\Run
    • ilass = "%Windows%\system\lsass.exe"

Step 7

Search and delete AUTORUN.INF files created by WORM_PALEVO.JB that contain these strings

[ Learn More ]
  • [autorun]
  • shellexecute=Key-Installer.exe
  • action=Open folder to view files
  • shell\default=Open
  • shell\default\command=Key-Installer.exe
  • shell=default

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PALEVO.JB. 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.

Step 9

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


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