ENSRT Incident Note ETS-i-2005-12593
The Enterasys 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 - WORM_SAVAGE.A
Release Date: 09/02/2005
Last Updated:
Overview
WORM_SAVAGE.A is a mass-mailing worm that spreads via an embedded SMTP engine to users located within the infected computer's Windows Address Book. Additionally, the worm spreads through peer-to-peer file sharing programs by placing worm copies inside the shared download directories of the different P2P programs.
Systems affected
Windows operating systemsSystems not affected
Linux and MAC/OSXDescription
WORM_SAVAGE.A arrives at a user's mailbox containing an attachment called "TMP.ZIP" and one of the follow e-mail subjects:
-am shocked about your document!
-Are you a spammer? (I found your email on a spammer website!?!)
-Bad Gateway: The message has been attached.
-Binary message is available.
-Can you confirm it?
-Delivered message is attached.
-Do not visit these sites!!!
-Encrypted message is available.
-ESMTP [Secure Mail System #334]: Secure message is attached.
-Mail transaction failed. Partial message is available.
-The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
-The message contains Unicode characters and has been sent as a binary attachment.
-You have visited illegal websites. I have a big list of the websites you surfed.
-You think it's funny? You are stupid idiot!!! I'll send the attachment to your ISP and then I'll be watching how you will go to jail, punk!!!
-Your credit card was charged for $500 USD. For additional information see the attachment.
WORM_SAVAGE.A also contains one of the following e-mail bodies:
- "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.
p 2004 Networks Associates Technology, Inc. All RightsReserved"
- "New terms and conditions for credit card holders
Herea 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 theWorld Wide Web.
Thank you,
The World Bank Group
2004 The World Bank Group, All Rights Reserved"
- "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! 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"
If the attached ZIP file is extracted and the embedded worm executed the following events will occur.
1) A file with garbage characters is created and opened with NOTEPAD.
2) Once NOTEPAD is cancelled by the user, the worm places itself into the Window's system directory.
3) Automatic restart of the worm is guaranteed through the addition of Windows registry entries.
4) The worm scans the Windows registry looking for SMTP servers to use with the e-mail propagation functionality.
5) E-mail targets are extracted from the infect machnie's Windows Address Book and additional e-mail addresses are created by prepending common names to different domains.
6) The worm places copies of itself into the download directories of common peer-to-peer file sharing programs with the hopes of further propagation.
7) The Windows' HOSTS file is altered to prevent traffic from the infected machine to reach Internet based security sites.
8) The worm removes registry entries for other possible worms which may have previously infected the machine causing them to no longer run. Additionally the other malware processes are terminated.
9) Lastly a backdoor is opened by connecting to a remote WEB server and waiting for commands from an attacker.
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.
Trojans or backdoor listeners if not addressed through prudent remediation steps, can compromise network and host security. Additionally, trojans and backdoor listeners potentially allow theft of information, unauthorized remote access, and damage to critical files.
Remediation
| Matrix N7 | X |
| Matrix E7 | X |
| Matrix E6 | X |
| Matrix E5 | X |
| Matrix E1 | X |
| VH | X |
| C-Series | X | B-Series | X |
Detection
Dragon signatures that detect WORM_SAVAGE.A can be retrieved via Dragon Live Update and is located in the Master Library within the ENSRT category. The previously existing seven signatures with the prefix "ENSRT:W32-MYDOOM-AO" can be copied into a custom library and deployed on a Dragon network sensor that is protecting the enterprise SMTP server to 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 the "ENSRT:W32-MYDOOM-AO" signatures should be used. A threshold parameter of at least three signature detections within a time span of 60 seconds should be used to mitigate the existence 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. In the near future ENSRT signatures will be automatically enabled.
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 quarantine 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://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM%5FSAVAGE%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:
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Version: 1.0 |
Date: 09/02/2005 |
Author: ENSRT STAFF |
Change |