Worm/RBot.328262 - Worm

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Summary

Full description

Statistics

Virus:	Worm/RBot.328262
Date discovered:	08/07/2005
Type:	Worm
In the wild:	No
Reported Infections:	Low
Distribution Potential:	Medium
Damage Potential:	Medium
Static file:	Yes
File size:	558.080 Bytes
MD5 checksum:	a36bf2770D4763d8f53ae224d9bcfb57
VDF version:	6.31.0.172

General Methods of propagation:
   • Local network

Alias:
   • Sophos: W32/Tilebot-HD

Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP

Side effects:
   • Registry modification
   • Makes use of software vulnerability
   • Third party control

Files It copies itself to the following location:
• %WINDIR%\lsass.exe

It overwrites the following files.
– %SYSDIR%\ftp.exe
– %SYSDIR%\tftp.exe

It deletes the initially executed copy of itself.

Registry The following registry keys are added in order to load the service after reboot:

– HKLM\SYSTEM\CurrentControlSet\Services\Spool SubSystem App
   • "Type"=dword:00000110
   • "Start"=dword:00000002
   • "ErrorControl"=dword:00000000
   • "ImagePath"="%WINDIR%\lsass.exe"
   • "DisplayName"="Spool SubSystem App"
   • "ObjectName"="LocalSystem"
   • "FailureActions"=%hex value%
   • "Description"="Spool SubSystem App"

The following registry keys are added:

– HKLM\SYSTEM\CurrentControlSet\Services\Spool SubSystem App\Security
   • "Security"=%hex value%

– HKLM\SYSTEM\CurrentControlSet\Services\Spool SubSystem App\Enum
   • "0"="Root\\LEGACY_SPOOL_SUBSYSTEM_APP\\0000"
   • "Count"=dword:00000001
   • "NextInstance"=dword:00000001

– HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_SPOOL_SUBSYSTEM_APP
   • "NextInstance"=dword:00000001

– HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_SPOOL_SUBSYSTEM_APP\
   0000
   • "Service"="Spool SubSystem App"
   • "Legacy"=dword:00000001
   • "ConfigFlags"=dword:00000000
   • "Class"="LegacyDriver"
   • "ClassGUID"="{8ECC055D-047F-11D1-A537-0000F8753ED1}"
   • "DeviceDesc"="Spool SubSystem App"

– HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_SPOOL_SUBSYSTEM_APP\
   0000\Control
   • "*NewlyCreated*"=dword:00000000
   • "ActiveService"="Spool SubSystem App"

– HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions
   • "windns"=%malware execution directory%\%executed file%

Network Infection In order to ensure its propagation the malware attemps to connect to other machines as described below.

It drops copies of itself to the following network shares:
   • c$\windows\system32
   • c$\winnt\system32
   • ADMIN$\system32
   • ADMIN$

Exploit:
It makes use of the following Exploits:
– MS02-061 (Elevation of Privilege in SQL Server Web)
– MS03-026 (Buffer Overrun in RPC Interface)
– MS03-049 (Buffer Overrun in the Workstation Service)
– MS04-007 (ASN.1 Vulnerability)
– MS04-011 (LSASS Vulnerability)

Infection process:
Creates an FTP script on the compromised machine in order to download the malware to the remote location.

Remote execution:
–It attempts to schedule a remote execution of the malware, on the newly infected machine. Therefore it uses the NetScheduleJobAdd function.

IRC To deliver system information and to provide remote control it connects to the following IRC Server:

Server: mail2.tik**********
Port: 9632;7412
Channel: #z#
Nickname: [P00|USA|%eight-digit random character string%]
Password: m00

– This malware has the ability to collect and send information such as:
    • CPU speed
    • Current user
    • Free disk space
    • Free memory
    • Malware uptime
    • Information about the network
    • Information about running processes
    • Size of memory
    • Information about the Windows operating system

– Furthermore it has the ability to perform actions such as:
    • Launch DDoS ICMP flood
    • Launch DDoS SYN flood
    • Launch DDoS UDP flood
    • Disable network shares
    • Download file
    • Edit registry
    • Enable network shares
    • Execute file
    • Kill process
    • Open remote shell
    • Perform DDoS attack
    • Perform network scan
    • Perform port redirection
    • Terminate malware
    • Updates itself

Backdoor Contact server:
The following:
• htp://www.littleworld.pe.kr/**********

This is done via the HTTP GET request on a PHP script.

Injection – It injects the following file into a process: %SYSDIR%\sfc_os.dll

    All of the following processes:
   • %SYSDIR%\winlogon.exe
   • %SYSDIR%\svchost.exe
   • %SYSDIR%\spoolsv.exe

Miscellaneous Mutex:
It creates the following Mutex:
• w7p5h9e5k7x5

Anti debugging
It checks if the following file is present:
• \\.\NTICE

File patching:
In order to increase the number of maximum connections it has the capability to modify the tcpip.sys. It may result in a corruption of that file and break network connectivity.
In order to disable Windows File Protection (WFP) it has the capability to modify the file sfc_os.dll at offset 0000E2B8. WFP is intended to avoid some of the common problems that cause DLL inconsistencies.

File details Programming language:
The malware program was written in MS Visual C++.

Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

See a brief description here.

Description inserted by Bogdan Iliuta on Fri, 13 Oct 2006 17:01 (GMT+1)
Description updated by Andrei Gherman on Tue, 21 Nov 2006 09:06 (GMT+1)

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