W32.Lad.1916

SUMMARY

W32.Lad.1916 is a virus that runs on all Windows 32-bit platforms (95/98/Me/NT/2000). It is a direct infector, and it infects Microsoft Portable Executable (PE) files. When executed, the virus does not go memory resident. Instead, the virus attempts to infect files in the Windows and the WindowsSystem folders, and in the same folder as the virus.

Its payload is executed on the 19th of every month, and it displays a short message.

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (Intelligent Updater) July 3, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

W32.Lad.1916 infects PE files, and it runs on all Win32 platforms. When first executed, the virus calculates an offset. This value will be used to patch the end of the viral body, so that control can be returned to the original host once the virus has finished executing.

Before attempting to infect files, the virus tries to find Kernel32.dll in memory. The virus has a list of functions inside itself, and it tries to locate the addresses of these functions inside the memory-resident Kernel32.dll file. Once it finds an address, it saves it in a table. The virus also tries to find functions from other .dll files. Only if the table was created successfully will the virus attempt to infect files.

The infection routine is very simple. The virus goes into a findfirst/findnext loop, finding .exe files in the Windows folder. The virus infects all PE files that it finds. It then goes into the same findfirst/findnext loop looking for .exe files in the WindowsSystem folder and the current folder (the folder from which the virus was executed).

Once the files are infected, the virus checks the system date. If it is the 19th of the month, it displays the following message:

Message box title: ADTWin32
Message: ADT for Windows

After executing the payload routine, the virus returns control to the original host.

Recommendations

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

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
3. If any files are detected as infected by W32.Lad.1916, click Repair.