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Date discovered:13/12/2012
Type:Backdoor Server
In the wild:Yes
Reported Infections:Low
Distribution Potential:Medium
Damage Potential:Medium
Static file:Yes
File size:49.152 Bytes
MD5 checksum:15870257aa24dac575191161c4d52781
VDF version:

 General Method of propagation:
   • Local network

   •  Symantec: W32.Toxbot
   •  Mcafee: W32/Sdbot.worm.gen.w
   •  Kaspersky:
   •  TrendMicro: WORM_SDBOT.BJA
   •  VirusBuster: Worm.Codbot.S

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

Side effects:
   • Drops malicious files
   • Records keystrokes
   • Registry modification
   • Makes use of software vulnerability
   • Third party control

 Files It copies itself to the following location:
   • %SYSDIR%\netddeclnt.exe

It deletes the initially executed copy of itself.

The following file is created:

– A file that is for temporary use and it might be deleted afterwards:
   • %TEMPDIR%\del.bat

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

– HKLM\SYSTEM\CurrentControlSet\Services\NetDDEclnt]
   • "Type"=dword:00000110
   • "Start"=dword:00000002
   • "ErrorControl"=dword:00000000
   • "ImagePath"="%malware execution directory%\\%executed file%"
   • "DisplayName"="Network DDE Client"
   • "ObjectName"="LocalSystem"
   • "FailureActions"=hex:05,00,00,00,00,00,00,00,00,00,00,00,01,00,00,00,42,00,42,\
   • 00,01,00,00,00,01,00,00,00
   • "Description"="Provides network transport and security for Dynamic Data Exchange (DDE) for programs running on the same computer or on different computers."

– HKLM\SYSTEM\CurrentControlSet\Services\NetDDEclnt\Enum]
   • "0"="Root\\LEGACY_NETDDECLNT\\0000"
   • "Count"=dword:00000001
   • "NextInstance"=dword:00000001
   • "INITSTARTFAILED"=dword:00000001

– [HKLM\SYSTEM\CurrentControlSet\Services\NetDDEclnt\Security]
   • "Security"=hex:01,00,14,80,90,00,00,00,9c,00,00,00,14,00,00,00,30,00,00,00,02,\

The following registry keys are added:

– [HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal\NetDDEclnt]
   • @="Service"

– [HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\NetDDEclnt]
   • @="Service

– [HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_NETDDECLNT\0000]
   • "Service"="NetDDEclnt"
   • "Legacy"=dword:00000001
   • "ConfigFlags"=dword:00000000
   • "Class"="LegacyDriver"
   • "ClassGUID"="{8ECC055D-047F-11D1-A537-0000F8753ED1}"
   • "DeviceDesc"="Network DDE Client"

– [HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_NETDDECLNT\0000\
   • "*NewlyCreated*"=dword:00000000
   • "ActiveService"="NetDDEclnt"

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

It makes use of the following Exploits:
– MS02-061 (Elevation of Privilege in SQL Server Web)
– MS03-007 (Unchecked Buffer in Windows Component)
– MS03-026 (Buffer Overrun in RPC Interface)
– MS04-011 (LSASS Vulnerability)

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

Slow down:
– Due to the multiple network threads created, an infected computer turns into a slow and barely usable machine.

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

Server: %unknown%
Channel: #exploit

Server: %unknown%
Channel: #raw

– This malware has the ability to collect and send information such as:
    • CPU speed
    • Free disk space
    • Free memory
    • Information about the network
    • Platform ID
    • Information about running processes
    • System directory
    • Windows directory

 Stealing It tries to steal the following information:

– A logging routine is started after keystrokes are typed that match one of the following strings:
   • bank
   • login
   • paypal
   • e-bay
   • ebay

 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:
   • PE-Crypt.Antideb

Description inserted by Catalin Jora on Wednesday, August 3, 2005
Description updated by Catalin Jora on Tuesday, August 23, 2005

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