Worm/Conficker - Worm

See also

Summary

Full description

Statistics

Virus:	Worm/Conficker
Date discovered:	14/01/2009
Type:	Worm
In the wild:	Yes
Reported Infections:	Medium
Distribution Potential:	Medium
Damage Potential:	Medium
Static file:	No
IVDF version:	7.01.01.115 - Wed, 14 Jan 2009 08:44 (GMT+1)

General Methods of propagation:
   • Local network
   • Mapped network drives
   • Peer to Peer

Aliases:
   • Symantec: W32.Downadup.B
   • Kaspersky: Net-Worm.Win32.Kido.fw
   • F-Secure: Worm:W32/Downadup.gen!A
   • Sophos: Mal/Conficker-A
   • Panda: Trj/Downloader.MDW
   • Grisoft: I-Worm/Generic.CJY
   • Eset: a variant of Win32/Conficker.AE worm
   • Bitdefender: Win32.Worm.Downadup.Gen

Similar detection:
   • Worm/Kido

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

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

Files It copies itself to the following locations:
   • %all shared folders% \RECYCLER\S-%number%\%random character string%.vmx
   • %ProgramFiles%\Internet Explorer\%random character string%.dll
   • %ProgramFiles%\Movie Maker\%random character string%.dll
   • %SYSDIR%\%random character string%.dll
   • %TEMPDIR%\%random character string%.dll
   • %ALLUSERSPROFILE%\Application Data\%random character string%.dll

The following file is created:

– %all shared folders%\autorun.inf This is a non malicious text file with the following content:
   • %random comments%
     shellexecute rundll32.exe %paths and filenames of malware copies%,%random character string%
     %random comments%

– %SYSDIR%\%two-digit random character string%.TMP Further investigation pointed out that this file is malware, too. Detected as: TR/Rootkit.Gen

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

– HKLM\SYSTEM\CurrentControlSet\Services\%random words%\
   Parameters\
   • ServiceDll" = "%paths and filenames of malware copies%"

– HKLM\SYSTEM\CurrentControlSet\Services\%random words%\
   • "ImagePath" = %SystemRoot%\system32\svchost.exe -k netsvcs
     "Type" = "4"
     "Start" = "4"
     "ErrorControl" = "4"

The following registry keys are changed:

– [HKLM\SYSTEM\CurrentControlSet\Services\wscsvc]
   Old value:
   • "Start"=dword:00000003
   New value:
   • "Start"=dword:00000004

– [HKLM\SYSTEM\CurrentControlSet\Services\wuauserv]
   Old value:
   • "Start"=dword:00000003
   New value:
   • "Start"=dword:00000004

– [HKLM\SYSTEM\CurrentControlSet\Services\BITS]
   Old value:
   • "Start"=dword:00000003
   New value:
   • "Start"=dword:00000004

– [HKLM\SYSTEM\CurrentControlSet\Services\ERSvc]
   Old value:
   • "Start"=dword:00000003
   New value:
   • "Start"=dword:00000004

– HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
   New value:
   • "Hidden"=dword:00000002
     "ShowCompColor"=dword:00000001
     "HideFileExt"=dword:00000000
     "DontPrettyPath"=dword:00000000
     "ShowInfoTip"=dword:00000001
     "HideIcons"=dword:00000000
     "MapNetDrvBtn"=dword:00000000
     "WebView"=dword:00000000
     "Filter"=dword:00000000
     "SuperHidden"=dword:00000000
     "SeparateProcess"=dword:00000000

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

It uses the following login information in order to gain access to the remote machine:

– The following list of passwords:
   • 000; 0000; 00000; 0000000; 00000000; 0987654321; 111; 1111; 11111;
      111111; 1111111; 11111111; 123; 123123; 12321; 123321; 1234; 12345;
      123456; 1234567; 12345678; 123456789; 1234567890; 1234abcd; 1234qwer;
      123abc; 123asd; 123qwe; 1q2w3e; 222; 2222; 22222; 222222; 2222222;
      22222222; 321; 333; 3333; 33333; 333333; 3333333; 33333333; 4321; 444;
      4444; 44444; 444444; 4444444; 44444444; 54321; 555; 5555; 55555;
      555555; 5555555; 55555555; 654321; 666; 6666; 66666; 666666; 6666666;
      66666666; 7654321; 777; 7777; 77777; 777777; 7777777; 77777777;
      87654321; 888; 8888; 88888; 888888; 8888888; 88888888; 987654321; 999;
      9999; 99999; 999999; 9999999; 99999999; a1b2c3; aaa; aaaa; aaaaa;
      abc123; academia; access; account; Admin; admin; admin1; admin12;
      admin123; adminadmin; administrator; anything; asddsa; asdfgh; asdsa;
      asdzxc; backup; boss123; business; campus; changeme; cluster;
      codename; codeword; coffee; computer; controller; cookie; customer;
      database; default; desktop; domain; example; exchange; explorer; file;
      files; foo; foobar; foofoo; forever; freedom; fuck; games; home;
      home123; ihavenopass; Internet; internet; intranet; job; killer;
      letitbe; letmein; login; Login; lotus; love123; manager; market;
      money; monitor; mypass; mypassword; mypc123; nimda; nobody; nopass;
      nopassword; nothing; office; oracle; owner; pass; pass1; pass12;
      pass123; passwd; password; Password; password1; password12;
      password123; private; public; pw123; q1w2e3; qazwsx; qazwsxedc; qqq;
      qqqq; qqqqq; qwe123; qweasd; qweasdzxc; qweewq; qwerty; qwewq; root;
      root123; rootroot; sample; secret; secure; security; server; shadow;
      share; sql; student; super; superuser; supervisor; system; temp;
      temp123; temporary; temptemp; test; test123; testtest; unknown; web;
      windows; work; work123; xxx; xxxx; xxxxx; zxccxz; zxcvb; zxcvbn;
      zxcxz; zzz; zzzz; zzzzz

IP address generation:
It creates random IP addresses while it keeps the first three 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: .\RECYCLER\S-%number%\%random character string%.vmx

Hosts – Access to the following domains is effectively blocked:
   • ahnlab; arcabit; avast; avg.; avira; avp.; bit9.; ca.; castlecops;
      centralcommand; cert.; clamav; comodo; computerassociates; cpsecure;
      defender; drweb; emsisoft; esafe; eset; etrust; ewido; f-prot;
      f-secure; fortinet; gdata; grisoft; hacksoft; hauri; ikarus; jotti;
      k7computing; kaspersky; malware; mcafee; microsoft; nai.;
      networkassociates; nod32; norman; norton; panda; pctools; prevx;
      quickheal; rising; rootkit; sans.; securecomputing; sophos; spamhaus;
      spyware; sunbelt; symantec; threatexpert; trendmicro; vet.; virus;
      wilderssecurity; windowsupdate

Miscellaneous Internet connection:
In order to check for its internet connection the following DNS servers are contacted:
   • http://www.getmyip.org
   • http://www.whatsmyipaddress.com
   • http://getmyip.co.uk
   • http://checkip.dyndns.org

Checks for an internet connection by contacting the following web sites:
   • baidu.com; google.com; yahoo.com; msn.com; ask.com; w3.org; aol.com;
      cnn.com; ebay.com; msn.com; myspace.com

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.

Rootkit Technology It is a malware-specific technology. The malware hides its presence from system utilities, security applications and in the end, from the user.

Method used:

Hooks the following API functions:
   • DNS_Query_A
   • DNS_Query_UTF8
   • DNS_Query_W
   • Query_Main
   • sendto

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 Alexander Neth on Fri, 16 Jan 2009 06:55 (GMT+1)
Description updated by Alexander Neth on Fri, 17 Jul 2009 09:36 (GMT+1)

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