W97M.ColdApe

SUMMARY

W97M.ColdApe is one of the first macro viruses that carry a payload that utilizes VBScript. The first payload creates a VBScript virus dropper while the second payload creates a VBScript that uses MS Outlook to send a lewd message to a well-known antivirus researcher.

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
• Target of Infection: Microsoft Word 97 documents

TECHNICAL DETAILS

Payload:

Both payloads below are executed if VBScript engine is installed. VBScript engine is installed in default MS Windows 98 installation and MS Internet Explorer 4.0 or later. Other version of MS Windows can have VBScript engine installed if Windows Scripting Host is installed.

On the first infection, this macro virus also drops C:HAPPY.VBS. This script file is a dropper of a VBScript virus. Norton Antivirus detects this script virus as Bloodhound.File.String.

The second payload utilizes MS Outlook to send an email message to the virus author and another email message to annoy an antivirus researcher. From the 5th or later until the last day of the first month of infection, W97M.ColdApe creates and runs a script file C:A4.VBS once a day. This script file sends two email messages using MS Outlook. The first email message is addressed to avm@nym.alias.net, and it contains the IP of the infected machine. The second email message is addressed to a well-known antivirus researcher. The second email contains a lewd message that uses MS Word user name setting.

Variant Notes:

Some W97M.ColdApe variants are polymorphic. Others may have different message body or email address on the payload.
W97M.ColdApe.B is polymorphic. The polymorphism uses MS Word user name and the system date and time

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

The dropped VBS files, C:A4.VBS and C:HAPPY.VBS need to be deleted.

Since the macro virus executes C:HAPPY.VBS, many VBS script file may get infected by this VBS virus. While NAV detects the infected VBS file(s) as Bloodhound.File.String, it does not repair infected VBS file(s). We recommend replacing the VBS file(s) with clean backup copies.

The following Windows Registry keys are created by the virus and should be removed:
· HKEY_CURRENT_USERSoftwareVB and VBA

Program SettingsOffice8.0

· HKEY_LOCAL_MACHINESOFTWAREMicrosoft

WindowsCurrentVersionRunAVM