Virus:Worm/Korgo.U
Date discovered:24/06/2004
Type:Worm
In the wild:Yes
Reported Infections:Low
Distribution Potential:Medium
Damage Potential:Medium
Static file:Yes
File size:9.728 Bytes
MD5 checksum:e73c129128c47f948f25f8745ebada4c

 General Method of propagation:
   • Local network


Aliases:
   •  Symantec: W32.Korgo.V
   •  Mcafee: W32/Korgo.worm.v
   •  Kaspersky: Net-Worm.Win32.Padobot.m
   •  TrendMicro: WORM_KORGO.V
   •  F-Secure: Net-Worm.Win32.Padobot.m
   •  Sophos: W32/Korgo-T
   •  Grisoft: Worm/Padobot.V
   •  Eset: Win32/Korgo.V
   •  Bitdefender: Win32.Worm.Korgo.U


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
   • Steals information
   • Third party control

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



It deletes the following file:
   • %SYSDIR%\ftpupd.exe

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

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



The values of the following registry keys are removed:

–  [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • Windows Update
   • 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]
   • ID="puqwcckndpcvandicr"
   • Client="1"

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

It drops a copy of itself to the following network share:
   • IPC$


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


IP address generation:
It creates random IP addresses while it keeps the first two octets from its own address. Afterwards it tries to establish a connection with the created addresses.


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: Xhttp://%current ip address%:%opened port%/%random character string%.exe


Slow down:
– You might also note a slight slow down due to the multiple network threads created.

 Backdoor The following ports are opened:

– %WINDIR%\Explorer.EXE on a random TCP port in order to provide a proxy server.
– %WINDIR%\Explorer.EXE on a random TCP port in order to provide an HTTP server.


Contact server:
All of the following:
   • http://www.citi-bank.ru/**********
   • http://www.0AB1c**********
   • http://www.redli**********
   • http://www.filesea**********
   • http://www.roboxcha**********
   • http://www.fethar**********
   • http://www.asech**********
   • http://www.master-**********
   • http://www.color-ba**********
   • http://www.kavk**********
   • http://www.cruto**********
   • http://www.kidos-ban**********
   • http://www.parex-ban**********
   • http://www.adult-emp**********
   • http://www.konfisk**********
   • http://www.xware.cj**********
   • http://www.mazafa**********

As a result it may send information and remote control could be provided. This is done via the HTTP GET request on a PHP script.


Sends information about:
    • Current malware status


Remote control capabilities:
    • Download file

 Injection –  It injects the following file into a process: %sysdir%\%random character string%.exe

    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:
   • u13i
   • u15
   • u19
   • uterm19
   • u12
   • u13
   • u14
   • u11
   • u18
   • u17
   • u8
   • u10
   • u16

 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 the following runtime packer:
   • UPX

Description inserted by Monica Ghitun on Thursday, November 8, 2007
Description updated by Monica Ghitun on Friday, November 9, 2007

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