ENSRT Incident Note ETS-i-2005-12572
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.
W32.Mediakill.A@mm
Release Date: 05/11/2005
Last Updated:
Overview
W32.Mediakill.A@mm is a mass mailing worm that sends a copy of itself to the first ten addresses in the Windows Address Book. The worm attempts to delete media files and threatens network security by terminating security related processes.
Details below will describe the characteristics of the W32.Mediakill.A@mm as well as provide detection, containment, and prevention techniques available through Enterasys Secure Networks solutions.
Systems affected
Windows operating systemsSystems not affected
Linux and MAC/OSXDescription
The W32.Mediakill.A@mm mass mailer arrives in the user's mailbox using a wide array of sender names. The e-mail subject and message body and attachment will consist of one of the following:
Subject: Learning Programming
Message Body: Hey, I'm learning ho to do computer proramming, and I wanted you to see my first program.
Attachment: MyProgram.exe
Subject: New Game
Message Body: Hey, I found a cool new game called ActionJo! You might like it check it out. There are a bunch of levels to go through, an it has cool graphics!
Attachment: ActionJoe5.exe
Subject: Good Security
Message Body: I found a new security program, that's really helping me with my computer. It's gotten rid of a bunch of viruses and trojans already. You might want to take a look at it.
Attachment: ChaSec03.exe
Subject: Outlook Update
Message Body: I found a new security update for OutLook. It says it's already blocked 3 different worms from getting to me, so I thought you'd want to update too. I've attached it, if you do.
Attachment: msOutLookUpd1.07.exe
Subject: Speed Up Your Computer
Message Body: Hey, I found a really cool program that speeds up windows! It really makes my computer go a lot faster, and it loads everything better too! You might want to try it.
Attachment: WinGas2005.exe
If the attached executable is launched, the PC will become infected and the W32.Mediakill.A@mm worm will attempt to copy itself into the one of several Windows system folders, using one of the following names:
syslw.exe
winupd.exe
msop.exe
rncmd.exe
mscs.exe
lsrsa.exe
msalph.exe
msrnd.exe
symlg.exe.
The worm will edit the system.ini file, the win.ini file, and system registry entries in an attempt to configure itself to run at Windows system startup. In addition, the W32.Mediakill.A@mm worm performs the following actions:
- Attempts to terminate security related processes.
- Attempts to delete files with specific extensions every Wednesday from the directories "C:\Documents and Settings" and "C:\Program Files".
- Displays the following message:
"Windows is attempting to update your Outlook. You maybe presented with windows asking you whether you want to allow access to Outlook from another program, these are normal. If you see them, please click the 'Yes'or 'Okay' button, as that Outlook can finish updating."
- Peruses the Windows address book and forwards copies of itself to the first ten addresses in that file.
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 signature to detect the W32.Mediakill.A@mm worm can be retrieved via Dragon Live Update and is located in the Master Library within the ENSRT category. The five individual signatures with the prefix "ENSRT:W32-MEDIAKILL-A" can be copied into a custom library.
Deploying the above signature group on a Dragon network sensor that is protecting the enterprise SMTP server can successfully 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. If utilizing the DIR solution, users can either be expunged from the network or placed in a quarantine VLAN. Once isolated, see your anti-virus vendor for Windows repair procedures for infected users.
References
http://securityresponse.symantec.com/avcenter/venc/data/w32.mediakill.a@mm.html
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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:
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Version: 1.0 |
Date: 05/11/2005 |
Author: ENSRT STAFF |
Change |