ENSRT Incident Note ETS-i-2005-12555
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.Kelvir.R
Release Date: 04/13/2005
Last Updated:
Overview
The W32.Kelvir.R worm spreads through the MSN Messenger application via a link that is part of the message. This hyperlink points to a website that contains a downloadable version of the worm. If the executable file is downloaded and launched, the Windows PC becomes infected with the Kelvir worm. The worm also drops a backdoor trojan onto the infected system.
Details below describe the characteristics of the W32.Kelvir.R 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 Kelvir.R worm arrives on the user's PC via an instant message from the MSN Messenger application containing a hyperlink to a web-based executable file from a known MSN contact. If the executable is both received and executed, the Microsoft Windows PC will become infected.
Once the worm has been launched, it will download an executable from an Internet WEB site that is a variant of the Trojan W32.Spybot.Worm
The W32.Kelvir.R worm sends a particular MSN message to each MSN contact on the infected machine. This message contains a WEB based hyperlink to a copy of the worm which if downloaded, will infect the machine. The instant message is simply one statement, "picture of you!", along with an executable link to a site that downloads the worm and the backdoor.
Lastly, the W32.Kelvir.R worm attempts to spread by exploiting the following vulnerabilities in the Windows Operating System:
Microsoft Windows DCOM RPC Interface Buffer Overrun Vulnerability
Microsoft Windows Local Security Authority Service Remote Buffer Overflow
Microsoft SQL Server 2000 or MSDE 2000 audit vulnerability
Threat Assessment
MSN Messenger worms if not addressed through prudent remediation steps may impact individual system performance and compromise security settings by 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 to detect the W32.Kelvir.R worm can be retrieved via Dragon Live Update and is located in the Master Library within the ENSRT category. The signature "ENSRT:W32-KELVIR-R-001" can be copied into a custom library and deployed on a Dragon network sensor that is protecting traffic flows to the Internet to 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
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.
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.
References
http://securityresponse.symantec.com/avcenter/venc/data/w32.kelvir.r.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: 04/13/2005 |
Author: ENSRT STAFF |
Change |