ENSRT Incident Note ETS-i-2005-12596

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_AHKER.K

Release Date: 09/21/2005
Last Updated:

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Overview

WORM_AHKER.K is a mass-mailing worm that spreads through the MAPI protocol and participates in a Distributed Denial of Service (DDOS) attack against "www.cnn.com".

Details below describe the characteristics of WORM_AHKER.K as well as provide detection, containment, and prevention techniques available through Enterasys Secure Networks solutions.

Systems affected

Windows operating systems

Systems not affected

Linux and MAC/OSX

Description

WORM_AHKER.K arrives via an e-mail with various subject lines and the message "Enjoy Bin Laden's & Saddam's latest mini-game!" in the body of the e-mail. Additionally, the worm e-mail contains an attachment named "Mini-Game.zip" which contains an embedded copy of the worm.

If WORM_AHKER.K is launched, the following actions are taken against the conquered PC.

1) The worm places a copy of itself in the Windows directory on the infected machine with the name of LSASS.EXE.
2) Places a copy of DDOS.EXE in the root directory of the infected Windows machine.
3) Downloads a copy of MSWINSCK.OCX from the Internet and places the file in the Windows system directory. After the download the worm executes the non-malicious MSWINSCK.OCX file producing a popup error message 'LoadLibrary("MSWINSCK.OCX") failed - The specified module could not be found.'
4) Creates registry entries to ensure the worm is restarted on Windows system bootup.
5) Spreads the worm via the MAPI mail interface to e-mail addresses collected from the infected machine.
6) Launches an ICMP Distributed Denial of Service attack against the Internet site "www.cnn.com".
7) Modifies the Windows HOSTS file to prevent connectivity from the infected PC to Internet related security sites.
8) Terminates specific anti-virus related applications.

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 N-Series	X
Matrix E7	X
Matrix E6	X
Matrix E5	X
Matrix E1	X
VH	X
C-Series	X
B-Series	X

Detection

Two specific Dragon signatures have been created to detect WORM_AHKER.K. These signatures can be retrieved via Dragon Live Update and are located in the Master Library within the ENSRT category. The "ENSRT:WORM-AHKER-K-001" signature can be copied into a custom library and deployed on Dragon sensors protecting the outbound SMTP traffic flow to the Internet. The "ENSRT:WORM-AHKER-K-002" signature can be copied into a custom library and deployed on internal Dragon network sensors to successfully detect end-user class machines which have become infected with the worm.

The "ENSRT:WORM-AHKER-K-002" signature is appropriate for use with the Enterasys Dynamic Intrusion Response (DIR) solution while the signature "ENSRT:WORM-AHKER-K-001" should be used for detection purposes only.
In addition, the ICMP analysis section of the Dragon Protocol Analysis Module can be deployed on network sensors to detect the large ICMP Denial of Service attack associated with Ahker.K worm.

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 provided a quarantine policy. 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%5FAHKER%2EK&VSect=T
http://securityresponse.symantec.com/avcenter/venc/data/w32.ahker.n@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:

Version: 1.0

Date: 09/21/2005

Author: ENSRT STAFF

Change

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