WORM_MYDOOM.DA

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It opens certain ports to access shared networks. It takes advantage of software vulnerabilities to propagate across networks.

Arrival Details

This worm may arrive via network shares.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This worm drops the following copies of itself into the affected system:

• %System Root%\csrss.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Update = "{malware path}\{malware name}.exe"

Propagation

This worm opens the following ports to access shared networks:

• TCP port 445

It uses the following user name and password to gain access to password-protected shares:

• User name: administrator
• Password: {any of the following}
  
  • !@#$%
  • &*()_+
  • 111111
  • 12345
  • 123456
  • 1234567
  • 54321
  • 654321
  • BUMBLE
  • admin
  • angel
  • asdfg
  • asdfgh
  • mail1
  • mail123
  • mail1234
  • passwd
  • password
  • test1234
  • web123
  • web1234
  • ~!@#$%

It takes advantage of the following software vulnerabilities to propagate across networks:

• (MS08-067) Vulnerability in Server Service Could Allow Remote Code Execution (958644)

Dropping Routine

This worm drops the following files:

• %System%\lsasvc.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

NOTES:

Once it gains access on the infected system, this worm drops a copy of itself as CSRSS.EXE in the ADMIN$ folder. It also deletes sharing permissions of the following folders:

• ADMIN$
• C$

This worm sends the IP address and Windows OS of the infected system to the remote user via email. It sends the information using the Simple Mail Transfer Protocol (SMTP) gmail-smtp-in.l.google.com; or its own SMTP engine. The email it sends has the following format:

Subject: {IP address of the infected system}|{Windows OS}
From: {BLOCKED}03@yahoo.com
To: {BLOCKED}001@gmail.com
Message body: none