ENSRT Incident Note ETS-i-2005-12524
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.
Worms - W32.Aimdes.B and W32.Aimdes.C@mm
Release Date: 02/17/2005
Last Updated:
Overview
W32.Aimdes.B and W32.Aimdes.C@mm are Microsoft Windows based instant messenger worms that contain an executable attachment which spreads via AOL Instant Messenger. The W32.Aimdes.C@mm variant uses the Microsoft Exchange Server MAPI protocol to spread as a mass-mailing worm.
W32.Aimdes.C@mm also known as:
Email-Worm.Win32.Anker.d, WORM_AHKER.D
Details below will describe the characteristics of the W32.Aimdes.B and W32.Aimdes.C@mm worms 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.Aimdes.B and W32.Aimdes.C@mm worms arrive as AOL instant messages with an attached executable of "party!!.pif" and the following message:
"Hey I went to a wild party last week! Check out the pics!!!"
In the case of the "W32.Aimdes.C@mm" the worm can also arrive in the user's mailbox as an e-mail with an attachment of "patch.zip" and one of the following subject lines:
Antivirus Update
Blaster strikes again...please read!
Destroy Blaster
New Computer Virus Protection!!
New worm on the looser please read
Protect your SYSTEM from new viruses!
Read it!
Read this for your PC's safety!!
Read this please!
The e-mail body of this worm contains the following:
"Dear user, a new variant of the worm 'Blaster' has been released a week ago!
It's spreading faster than it ever did, this version of Blaster has been classified as 'Category 5'.
Please click on the following link to understand how bad is a worm classified in Category 5:
http://securityresponse.symantec.com/avcenter/
threat.severity.html#category
Symantec has developped a new 'patch' file which will prevent the new variant of Blaster to be executed and keep your system safe and clean.
The Patch file can be found in the attachment, please make sure you install it before being infected, because if you're already infected, the patch file
cannot fix/remove this type of threat as it's not yet studied quite good.
Symantec strongly recommends you to download and install the patch file before it's too late!
Symantec will soon release the 'Removal Tool' for this threat.
So if you don't often visit Symantec.com, we recommend you to visit us everyday to be in touch with the news of this type of threat.
P.S: We would like to thank Mr.Bazzi for making this patch file.
Regards,
Symantec, http://www.symantec.com"
If the attached executable file from either the mass mailing or AOL instant messenger component is launched, the worm will infect the PC and begin the replication process. First, the worms place new files with the name "party!!.pif", "Norton.exe", and "sys32dll.exe" onto the file system of the infected PC and then alters registry entries and the Windows Startup folder causing the worms to be launched at Windows boot time.
Secondly, both Aimdes worms attempt to disable numerous system and security processes in a effort to further reduce the security of the infected PC.
The third action of the Aimdes worms is to proliferate the worm to other users on the host's buddy list through AOL Instant Messenger attachment.
Lastly, the W32.Aimdes.C@mm variant will use the Microsoft Exchange Server MAPI protocol to send an e-mail containing a file named "patch.zip" to all the addresses found in the Outlook Address book .
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.
AOL Instant 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.
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.Aimdes.B and W32.Aimdes.C@mm worms can be retrieved via Dragon Live Update. These signatures are located in the Master Library within the ENSRT category.
The ENSRT:W32-AIMDES-B-C-AIM signature is utilized to detect the AOL Instant Messenger communication that is sent along with the attached file that propagates the worm. Deploy this signature on Dragon NIDS devices protecting end-user switch ports.
The ENSRT:W32-AIMDES-B-C-001 detects the worm as it propogates to external mail domains as it is sent between the Microsoft Exchange Server and the SMTP server. Deploy this signature on Dragon NIDS devices protecting the pathways to SMTP servers.
If utilizing Dynamic Intrusion Response (DIR), a Dragon Alarmtool policy that consists of an event group containing the "ENSRT:W32-AIMDES-B-C-AIM" signature should be used. Note: The "ENSRT:W32-AIMDES-B-C-001" should not be used with DIR as it does not detect the Aimdes worm as it travels from a user port.
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 quarentine VLAN or disabling the associated switch port for the user.
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.aimdes.b.html
http://securityresponse.symantec.com/avcenter/venc/data/w32.aimdes.c@mm.html
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM%5FAIMDES%2EC&VSect=P
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM%5FAIMDES%2EB
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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: 02/17/2005 |
Author: ENSRT STAFF |
Change |