SEVERITY: CRITICAL New Worm: Nachi, Blaster-D, Welchia
Date: Tuesday, August 19 @ 16:00:00 CEST
Topic: Security
Heads up gang another new worm is out in the wild - this time it
leverages the exploits patched in MS03-026 as well as MS03-007.
New Worm: Nachi, Blaster-D, Welchia
SEVERITY: CRITICAL
DATE: 08/18/2003
PRODUCTS AFFECTED: Windows 2000 and XP, Internet Information Services
5.0
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WHAT IS IT?
A new worm is spreading in the wild. The Microsoft Product Support
Services Security Team is issuing this alert to advise customers to be
on the alert for this virus as it spreads in the wild. Customers are
advised to review the information and take the appropriate action for
their environments.
IMPACT OF ATTACK: Network Propagation, Patch Installation
TECHNICAL DETAILS:
Similar to the earlier Blaster worm and its variants, this worm also
exploits the vulnerability patched by Microsoft Security Bulletin
MS03-026, and instructs target systems to download its copy from the
affected system using the TFTP program.
In addition to exploiting the RPC vulnerability patched by Microsoft
Security Bulletin MS03-026 this worm also uses a previously patched
vulnerability in Microsoft Security Bulletin MS03-007 directed at IIS
5.0 over port 80 to propagate to un-patched systems.
In addition upon successful infection this worm also patches systems
with the patch for Microsoft Security Bulletin MS03-026. It does this by
first determining the operating system and then downloading the
associated patch for that operating system.
For additional details on this worm from anti-virus software vendors
participating in the Microsoft Virus Information Alliance (VIA) please
visit the following links:
Network Associates:
http://vil.nai.com/vil/content/v_100559.htm
Trend Micro:
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_MSB
LAST.D
Symantec
http://securityresponse.symantec.com/avcenter/venc/data/w32.welchia.worm
.html
For more information on Microsoft's Virus Information Alliance please
visit this link: http://www.microsoft.com/technet/security/virus/via.asp
Please contact your Antivirus Vendor for additional details on this
virus.
PREVENTION:
Turn on Internet Connection Firewall (Windows XP or Windows Server 2003)
or use a third party firewall to block incoming TCP ports 80, 135, 139,
445 and 593; UDP ports 135, 137, 38.
To enable the Internet Connection Firewall in Windows XP please see the
instructions below or visit this KnowledgeBase Article:
http://support.microsoft.com/?id=283673
* In Control Panel, double-click Networking and Internet
Connections, and then click Network Connections.
* Right-click the connection on which you would like to enable
ICF, and then click Properties.
* On the Advanced tab, click the box to select the option to
Protect my computer or network.
This worm utilizes two previously-announced vulnerabilities as part of
its infection method. Because of this, customers must ensure that their
computers are patched for the vulnerabilities that are identified in the
following Microsoft Security Bulletins.
Microsoft Security Bulletin MS03-026
http://www.microsoft.com/technet/security/bulletin/MS03-026.asp
Microsoft Security Bulletin MS03-007
http://www.microsoft.com/technet/security/bulletin/MS03-007.asp
In order to assist customers with the installation of the patch for
Microsoft Security Bulletin MS03-026 Microsoft has released a tool which
can be used to scan a network for the presence of systems which have not
had the MS03-026 patch installed. More details on this tool are
available in Microsoft Knowledge Base article 826369.
RECOVERY:
If your computer has been infected with this virus, please contact your
preferred antivirus vendor or Product Support Services for assistance
with removing it.
RELATED KB ARTICLES:
http://support.microsoft.com/default.aspx?scid=kb;en-us;826234
This article will be available within 24 hours.
RELATED SECURITY BULLETINS:
Microsoft Security Bulletin MS03-026
http://www.microsoft.com/technet/security/bulletin/MS03-026.asp
Microsoft Security Bulletin MS03-007
http://www.microsoft.com/technet/security/bulletin/MS03-007.asp
VIRUS ALERT LINK:
http://www.microsoft.com/technet/security/virus/alerts/nachi.asp
As always please make sure to use the latest Anti-Virus detection from
your Anti-Virus vendor to detect new viruses and their variants.
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