ENSRT Incident Note ETS-i-2005-12569

The Enterasys Networks Security Response Team (ENSRT) publishes incident notes to provide information for our constituents to raise awareness of issues deemed threatening to the security and integrity of our customers.

Worm - W32.Ezio.A@mm

Release Date: 05/09/2005
Last Updated:

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Overview

The W32.Ezio.A@mm worm propagates by sending copies of itself via e-mail and peer to peer file sharing networks. Furthermore, the worm threatens system security by disabling security related software and preventing Internet access to security sites.

Also known as: WORM_EZIO.A

Details below describe the characteristics of the W32.Ezio.A@mm worm as well as provide detection, containment, and prevention techniques available through Enterasys Secure Networks solutions.

Systems affected

Windows operating systems

Systems not affected

Linux and MAC/OSX

Description

The W32.Ezio.A@mm worm arrives on the user's PC via an e-mail with an enclosed attachment. If the attachment is executed, the Microsoft Windows PC will become infected.

The worm e-mail message contains following Subject line:

- Mail Error

The worm e-mail contains the following message body:

- Please see the attached document for details.

The worm e-mail contains the following attachment:

- document.zip

Once the W32.Ezio.A@mm worm has been executed, the following actions are taken against the infected PC.

1) The worm displays the following error message: "Can’t open MFC87Eng.dll".
2) The worm places numerous files into the Windows 'help' directory with one of them being an executable file named "svchost.exe".
3) The worm adds registry entries to ensure that the dropped executable "svchost.exe " is restarted at Windows boot time.
4) The worm attempts to spread through file sharing networks by replacing files within shared folders with copies of the worm.
5) The worm attempts proliferation via embedded e-mail client using addresses gather from html and text files located on the infected PC.
6) The worm attempts to disable security related software by deleting Windows registry entries.
7) The worm appends entries to the system "hosts" file to prevent Internet access to certain security related sites.

Threat Assessment

Mass-mailing worms if not addressed through prudent remediation steps may congest mail servers and/or degrade network performance. Mass-mailing worms may impact individual system performance and compromise security settings allowing unauthorized remote access to the compromised host.

Remediation

Matrix N7	X
Matrix E7	X
Matrix E6	X
Matrix E5	X
Matrix E1	X
VH	X
C-Series	X

Detection

A specific Dragon signatures that detects the W32.Ezio.A@mm worm can be retrieved via Dragon Live Update and is located in the Master Library within the ENSRT category. The signature "ENSRT:W32-EZIO-A-001" can be copied into a custom library and deployed on a Dragon network sensor that is protecting the enterprise SMTP server to detect end-user class machines which have become infected with the worm.

NOTE: All signatures in the ENSRT library are disabled by default. These signatures must be enabled after they are imported into a custom library if they are to be successfully deployed.

Prevention

Trusted End System solutions are capable of monitoring various end system activity. TES is able to take immediate action such as firewalling specific IPs, TCP/UDP ports, applications, or placing the user into a Quarantine policy or VLAN until end system threat is mitigated. Learn more at: http://www.enterasys.com/solutions/secure-networks/trusted_end_system/

Containment

Using Enterasys Policy Manager, enforce a policy that allows SMTP traffic from end user PCs to authorized SMTP mail servers and blocks SMTP traffic to unauthorized end users or unknown Internet systems. If the SMTP protocol is not implemented for end users within the enterprise, consider implementing a policy blocking SMTP traffic from end user ports.

Repair

Monitor Dragon Realtime Console for alerts that end-user PCs have become infected with the virus. Once isolated, see your anti-virus vendor for Windows repair procedures for infected users.

References

http://securityresponse.symantec.com/avcenter/venc/data/w32.ezio.a@mm.html
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM%5FEZIO%2EA&VSect=T

This document and the information contained herein are intended solely for informational use. Enterasys Networks, Inc. makes no representations or warranties of any kind, whether expressed or implied, with respect to this information and assumes no responsibility for its accuracy or completeness. Enterasys Networks, Inc. hereby disclaims all liability and warranty for any information contained herein and all the material and information herein exists to be used only on an "as is" basis. More specific information may be available on request. By your review and/or use of the information contained herein, you expressly release Enterasys from any and all liability related in any way to this information.

A copy of the text of this section is an uncontrolled copy, and may lack important information or contain factual errors. All information herein is Copyright ©Enterasys Networks, Inc. All rights reserved. All information above is subject to change without notice.

Revision History:

Version: 1.0

Date: 05/09/2005

Author: ENSRT STAFF

Change

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