ENSRT Incident Note ETS-i-2005-12566
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.Sober.O@mm
Release Date: 05/03/2005
Last Updated:
Overview
W32.Sober.O@mm is a mass-mailing worm that arrives as an e-mail attachment with a body that can be written in either English or German. The worm proliferates further with the use of an embedded SMTP engine.
Also known as:
Win32.Sober.N [Computer Associates], Sober.P [F-Secure], W32/Sober.p@MM [McAfee], W32/Sober-N [Sophos], WORM_SOBER.S [Trend Micro]
Details below describe the characteristics of the W32.Sober.O@mm worm 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.Sober.O@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 mail message contains one of the following Subject lines:
ENGLISH:
- Re:Your Password
- Re:Registration Confirmation
- Re:Your email was blocked
- Re:mailing error
- Re: [blank]
GERMAN:
- Ihr Passwort
- Mail-Fehler!
- Ihre E-Mail wurde verweigert
- Ich bin's, was zum lachen ;)
- Glueckwunsch: Ihr WM Ticket
- WM Ticket Verlosung
- WM-Ticket-Auslosung
The e-mail contains one of the following bodies:
ENGLISH:
- ok ok ok,,,,, here is it
- Account and Password Information are attached!
Visit: http:/ /www.[random domain]
- This is an automatically generated E-Mail Delivery Status Notification.
Mail-Header, Mail-Body and Error Description are attached
GERMAN:
-Passwort und Benutzer-Informationen befinden sich in der beigefuegten Anlage.
http:/ /www.[random domain]
*-* MailTo: PasswordHelp
- Diese E-Mail wurde automatisch erzeugt
Mehr Information finden Sie unter http:/ /www.[random domain]
Folgende Fehler sind aufgetreten:
Fehler konnte nicht Explicit ermittelt werden
Aus Datenschutzrechtlichen Gruenden, muss die vollstaendige E-Mail incl. Daten gezippt & angehaengt werden.
Wir bitten Sie, dieses zu beruecksichtigen.
Auto ReMailer#
- Nun sieh dir das mal an
Was ein Ferkel ....
- Herzlichen Glueckwunsch,
beim Run auf die begehrten Tickets fr die 64 Spiele der Weltmeisterschaft 2006 in Deutschland sind Sie
dabei.Weitere Details ihrer Daten entnehmen Sie bitte dem Anhang.
St. Rainer Gellhaus
--- Pressesprecher Jens Grittner und Gerd Graus
--- FIFA Fussball-Weltmeisterschaft 2006
--- Organisationskomitee Deutschland
--- Tel. 069 / 2006 - 2600
--- Jens.Grittner@ok2006.de
--- Gerd.Graus@ok2006.de
The e-mail contains one of the following attachments:
ENGLISH:
- our_secret.zip
- mail_info.zip
- error-mail_info.zip
- account_info.zip
- account_info-text.zip
GERMAN:
- LOL.zip
- autoemail-text.zip
- _PassWort-Info.zip
- Fifa_Info-Text.zip
- okTicket-info.zip
Once the PC is infected, the worm displays an error window with the message:
"Error: CRC not complete"
At this point the worm writes numerous files into the Windows 'system' and 'Connection Wizard\Status' directories as well as adds registry entries to ensure that the worm restarts on each Windows system reboot.
Next, the W32.Sober.O@mm skims e-mail addresses from certain types of system files and begins the proliferation process with an embedded SMTP engine.
Lastly, if Symantec anti-virus software is found on the infected PC, the "LiveUpdate" executable files are deleted and a copy of the worm is then placed into the "LiveUpdate" directory with the name "luall.exe".
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
Specific Dragon signatures that detect the W32.Sober.O@mm worm can be retrieved via Dragon Live Update and are located in the Master Library within the ENSRT category. The eight signatures with the prefix "ENSRT:W32-SOBER-O" 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.
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-SOBER-O" family 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.
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://securityresponse.symantec.com/avcenter/venc/data/w32.sober.o@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: 05/03/2005 |
Author: ENSRT STAFF |
Change |