Sophos

W32/Maslan-B

Aliases
  • Net-Worm.Win32.Maslan.a
Category
Type
What to do
Prevalence low high

Summary

 
How it spreads
  • Email attachments
  • Network shares
Affected operating systems Windows
Characteristics
  • Drops more malware
Protection available since 13 December 2004 14:22:12 (GMT)
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Action

Please follow the instructions for removing worms.

Windows NT/2000/XP/2003

In Windows NT/2000/XP/2003 you will also need to edit the following registry entry. The removal of this entry is optional in Windows 95/98/Me. Please read the warning about editing the registry.

At the taskbar, click Start|Run. Type 'Regedit' and press Return. The registry editor opens.

Before you edit the registry, you should make a backup. On the 'Registry' menu, click 'Export Registry File'. In the 'Export range' panel, click 'All', then save your registry as Backup.

Locate the HKEY_LOCAL_MACHINE entry:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Microsoft Windows DHCP
%SYSTEM%\___r.exe

and delete it if it exists.

Close the registry editor.

More Information

W32/Maslan-B is a Windows worm which spreads by mailing itself to addresses found on the infected computer.

The worm also spreads to network shares with weak passwords and by using the LSASS security exploit (MS04-011) and the RPC-DCOM security exploit (MS03-039).

When run W32/Maslan-B copies itself to the Windows System folder as ___u and creates the files ___e, ___j.dll, ___n.exe and ___r.exe in the Windows System folder.

___n.exe is being detected as Troj/Sdbot-RV.
___j.dll is being detected as W32/Maslan-A.

The worm also creates the following registry entry so that it runs automatically on user logon:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Microsoft Windows DHCP
%SYSTEM%\___r.exe

W32/Maslan-B attempts to create the folder %ROOOT%\___b and also tries to copy itself as random filenames to folders with names that contains the words "share", "setup", "distr" or "download".

The worm also tries to create the following files:

%SYSTEM%\___AlaFtp
%SYSTEM%\___AlaDdos
%SYSTEM%\___AlaMail
%SYSTEM%\___AlaScan
%SYSTEM%\___Prior
%SYSTEM%\___m
%SYSTEM%\___t

These files are non-viral and may be safely deleted.

W32/Maslan-B also attempts to perform distributed denial-of-service (DDoS) attacks.

Emails sent by W32/Maslan-B have the following characteristics:

Subject Title: 123

File attachment: Playgirls2.exe

Message Body:

Hello <random name>,

--Best regards,
<random name>

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