Virus:Worm/Korgo.F.var
Date discovered:28/10/2005
Type:Worm
In the wild:No
Reported Infections:Low
Distribution Potential:Medium
Damage Potential:Medium
Static file:Yes
File size:11.391 Bytes
MD5 checksum:ca47a36342c23f5c291ae4fc6d4f6416
VDF version:6.32.00.123

 General Method of propagation:
   • Local network


Aliases:
   •  Symantec: W32.Korgo.R
   •  Mcafee: W32/Korgo.worm.z
   •  Kaspersky: Net-Worm.Win32.Padobot.gen
   •  TrendMicro: WORM_KORGO.Z
   •  Grisoft: Worm/Padobot.AB
   •  VirusBuster: Worm.Korgo.Z
   •  Bitdefender: Win32.Worm.Korgo.Z


Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003


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

 Files It copies itself to the following location:
   • %SYSDIR%\%random character string%.exe



It deletes the following file:
   • %malware execution directory%\ftpupd.exe

 Registry The following registry key is added in order to run the process after reboot:

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • "System Update" = "%SYSDIR%\%random character string%.exe"



The values of the following registry keys are removed:

–  [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • MS Config v13
   • avserve2.exeUpdate Service
   • avserve.exe
   • Windows Update Service
   • WinUpdate
   • SysTray
   • Bot Loader
   • System Restore Service
   • Disk Defragmenter
   • Windows Security Manager

–  [HKLM\Software\Microsoft\Wireless]
   • Client



The following registry key is added:

– [HKLM\Software\Microsoft\Wireless]
   • "Client" = "1"
   • "ID" = "%random character string%"

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


Exploit:
It makes use of the following Exploit:
– MS04-011 (LSASS Vulnerability)


IP address generation:
It creates random IP addresses and tries to establish a connection with them.


Infection process:
It makes the compromised machine download the malware from the infected source computer.
The downloaded file is stored on the compromised machine as: %SYSDIR%\%random character string%

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

Server: broadway.ny.us.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: brussels.be.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: caen.fr.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: ced.dal.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: coins.dal.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: diemen.nl.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: flanders.be.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: gaspode.zanet.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: graz.at.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: lia.zanet.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: london.uk.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: los-angeles.ca.us.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: lulea.se.eu.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: moscow-advokat.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: ozbytes.dal.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: qis.md.us.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: vancouver.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: viking.dal.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

Server: washington.dc.us.**********
Port: 6667
Server password: %random character string%
Channel: #taty
Nickname: %random character string%_13

 Backdoor The following ports are opened:

– explorer.exe on a random TCP port in order to provide an HTTP server.
– explorer.exe on TCP port 3067 in order to provide backdoor capabilities.

 Injection – It injects itself as a remote thread into a process.

    Process name:
   • explorer.exe

   If the malware fails, it continues running as a process.
   If successful, the malware process terminates while the injected part remains active.

 Miscellaneous Mutex:
It creates the following Mutexes:
   • uterm13i
   • u14
   • u13i
   • u13
   • u12
   • u11
   • u10
   • u9
   • u8

 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.

Description inserted by Iulia Diaconescu on Tuesday, April 4, 2006
Description updated by Iulia Diaconescu on Wednesday, April 5, 2006

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