ENSRT Incident Note ETS-i-2005-12589
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 - WORM_BAGLE.BM
Release Date: 08/08/2005
Last Updated:
Overview
WORM_BAGLE.BM is a mass-mailing worm that opens a backdoor on TCP port 9030 and listens for commands from a remote attacker.
Details below describe the characteristics of WORM_BAGLE.BM 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
WORM_BAGLE.BM arrives via an e-mail with varied subject and message bodies and one of the following attachments containing the filetype of "zip" or "exe":
-Details
-Document
-Info
-Information
-Message
-MoreInfo
-Readme
-Sources
-text_document
-Updates
If the executable is launched, the following steps in the worm propagation process occur.
1) Downloads a copy of the worm into the Window's system directory as WINHOST.EXE.
2) Creates registry entries to ensure the startup of the worm upon Windows bootup.
3) Attempts to download an additional executable worm component from the Internet.
4) Attempts to proliferate through different file sharing mechanisms by placing copies of itself in directories containing the string "shar".
5) Harvests e-mail addresses from the conquered PC's Windows Address Book (WAB) as well as from certain system files for use by the mass mailing component.
6) Terminates numerous security and anti-virus related processes.
7) Opens a backdoor listener on TCP 9030 and waits for commands from a remote 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 |
Detection
A specific Dragon signature that detects the WORM_BAGLE.BM worm can be retrieved via Dragon Live Update and is located in the Master Library within the ENSRT category. The signature "ENSRT:WORM-BAGLE-BM-001" can be copied into a custom library and deployed on a Dragon network sensor that is protecting the enterprise Internet connections 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 signature "ENSRT:W32-BAGLE-BM-001" 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.
Internet or edge facing firewalls should be configured with a default 'Deny' policy and contain 'Permit' policies for only needed services and applications. Furthermore, careful inspection of firewall policies that allow TCP traffic streams to be initiated from the Internet into internal enterprise resources is required. These policies should only allow specific protocols to trusted servers thereby combating the increased use of random TCP ports by Internet Trojans and worms.
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.
Scan all clients and servers for newly opened TCP ports that did not appear in previous TCP scans. If viruses are detected apply appropriate removal tools on each client and server that have the open ports (See your anti-virus solution for removal instructions).
References
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM%5FBAGLE%2EBM&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: 08/08/2005 |
Author: ENSRT STAFF |
Change |