ENSRT Incident Note ETS-i-2005-12519
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.Mydoom.AO@mm
Release Date: 02/02/2005
Last Updated: 02/04/2005
Overview
W32.Mydoom.AO@mm is a Microsoft Windows mass-mailing worm containing an executable attachment that spreads via an embedded SMTP engine as well as through Windows file shares.
Details below will describe the characteristics of the W32.Mydoom.AO@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.Mydoom.AO@mm mass mailer arrives in the user mailbox as an e-mail with one of the following subject lines:
- "Attention!!!"
- "Do not reply to this email"
- "Error"
- "Good day"
- "hello"
- "Mail Delivery System"
- "Mail Transaction Failed"
- "Server Report"
- "Status"
The email also contains one of the following e-mail bodies:
- "The message contains Unicode characters and has been sent as a binary attachment."
- "The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment."
- "Mail transaction failed. Partial message is available."
- "Thank you for registering at WORLDXXXPASS.COM
All your payment info, login and password you can find in the attachment file.
It's a real good choise to go to WORLDXXXPASS.COM"
- "Attention! New self-spreading virus!
Be careful, a new self-spreading virus called "RTSW.Smash" spreading very fast via e-mail and P2P networks. It's about two million people infected and it will be more.
To avoid your infection by this virus and to stop it we provide you with full information how to protect yourself against it and also including free remover. Your can find it in the attachment.
c 2004 Networks Associates Technology, Inc. All Rights Reserved"
- "New terms and conditions for credit card holders
Here a new terms and conditions for credit card holders using a credit cards for making purchase in the Internet in the attachment. Please, read it carefully. If you are not agree with new terms and conditions do not use your credit card in the World Wide Web.
Thank you,
The World Bank Group
c 2004 The World Bank Group, All Rights Reserved"
- "Attention! Your IP was logged by The Internet Fraud Complaint Center
Your IP was logged by The Internet Fraud Complaint Center. There was a fraud attempt logged by The Internet Fraud Complaint Center from your IP. This is a serious crime, so all records was sent to the FBI. All information you can find in the attachment. Your IP was flagged and if there will be anover attemption you will be busted.
This message is brought to you by the Federal Bureau of Investigation and the National White Collar Crime Center"
The W32.Mydoom.AO@mm e-mail as described above also contains an executable attachment with one of the following filetypes:
-".bat"
-".cmd"
-".exe"
-".pif"
-".scr"
-".zip"
If the attached executable file is launched, the mass mailling worm will infect the PC and begin the replication process. First, the worm places a new file with the name "lsasrv.exe" into the Windows system directory and causes it to be launched at Windows boot time by updating certain system registry keys.
The second step involves the creation of a file containing useless data in the current user's Windows "profile" folder and then uses "Notepad" to display the contents of this file.
The third step the worm takes is to place executable copies of the worm onto any available peer-to-peer file sharing folders that may exist on the conquered PC with one of the following names:
- "porno"
- "NeroBROM6.3.1.27"
- "avpprokey"
- "Ad-awareref01R349"
- "winxp_patch"
- "adultpasswds"
- "dcom_patches"
- "K-LiteCodecPack2.34a"
- "activation_crack"
- "icq2004-final"
- "winamp5"
The fourth step the W32.Mydoom.AO@mm worm attempts is to disable numerous system and security processes such as anti-virus software, download additional worm components from the Internet, and alter the Windows system host file in an attempt to prevent network access to Internet related security companies.
Lastly, the worm gathers e-mail addresses from the Windows address book as well as other PC files and uses its own embedded SMTP engine to further propagate the worm.
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.Mydoom.AO@mm worm can be retrieved via Dragon Live Update and is located in the Master Library within the ENSRT category. The seven individual signatures with the prefix "ENSRT:W32.Mydoom.AO@mm" 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.
If utilizing Dynamic Intrusion Response (DIR), a Dragon Alarmtool policy that consists of an event group that contains all of the signatures within the "ENSRT:W32.Mydoom.AO@mm" family should be used. A threshold parameter of at least three signature detections within a timespan of 60 seconds should be used to mitigate the existance of false positives.
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
The Enterasys Dynamic Intrusion Response (DIR) solution can be utilized to remove infected end-users from the enterprise network by detecting the infection with a Dragon NIDS signature (see "Detection" section of this report), locating the user's connection point using Automated Security Manager's location services module, and either placing the user in a quarentine VLAN or disabling the associated switch port for the user.
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.mydoom.ao@mm.html
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:
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Version: 1.0 |
Date: 02/02/2005 |
Author: ENSRT STAFF |
Change |