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AUSCERT External Security Bulletin Redistribution
ESB-2003.0053 -- ISS Security Brief
Microsoft SQL Slammer Worm Propagation
26 January 2003
AusCERT Security Bulletin Summary
Product: MS-SQL Server
Operating System: Windows
Impact: Execute Arbitrary Code/Commands
Denial of Service
Access Required: Remote
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ISS X-Force has learned of a worm that is spreading via Microsoft SQL
servers. The worm is responsible for large amounts of Internet traffic as
well as millions of UDP/IP probes at the time of this alert's publication.
This worm attempts to exploit MS/SQL servers vulnerable to the SQL Server
Resolution service buffer overflow (CVE CAN-2002-0649). Once a vulnerable
computer is compromised, the worm will infect that target, randomly select
a new target, and resend the exploit and propagation code to that host.
Although the Slammer worm is not destructive to the infected host, it does
generate a damaging level of network traffic when it scans for additional
targets. A large amount of network traffic is created by the worm, which
scans random IP addresses for vulnerable servers.
The Slammer worm propagates via Microsoft SQL installations without patches
from Microsoft Security bulletin MS02-039 or higher. The main function of
the Slammer worm is to continue propagation. No DDOS or backdoor
functionality is incorporated into the worm. Infection can be removed with
a reboot, however without protection in place, it is likely that vulnerable
servers will be quickly re-infected.
The Slammer worm loads Kernel32.dll and WS2_32.dll and then calls
GetTickCount which is used as a seed for a random IP address routine. This
routine then continuously sends exploit and propagation code across port
1434/UDP until the SQL Server process is shut down.
The Slammer worm simply seeks to replicate itself and does not try to
further compromise servers or retain access to compromised hosts.
ISS X-Force recommends that system administrators immediately take steps to
protect their networks.
The following ISS updates address the issues described in this alert. These
updates are available from the ISS Download center
RealSecure Network Sensor XPU 20.4 and XPU 5.3 (made available 9/17/02) or
Internet Scanner XPU 6.15 (made available 7/25/02).
Additionally ISS X-Force recommends blocking UDP port 1433 and 1434 traffic
to protect SQL Server databases with a firewall or packet filter.
Microsoft SQL Server customers should refer to the following address for
information and securing Microsoft SQL Server against this buffer overflow:
NGSSoftware Insight Security Research Advisory #NISR25072002,
"Unauthenticated Remote Compromise in MS SQL Server 2000" at
Microsoft Security Bulletin MS02-039, "Buffer Overruns in SQL Server 2000
Resolution Service Could Enable Code Execution (Q323875)" at
CERT Advisory CA-2002-22, "Multiple Vulnerabilities in Microsoft SQL Server"
CERT Vulnerability Note VU#484891, "Microsoft SQL Server 2000 contains stack
buffer overflow in SQL Server Resolution Service" at
NGSSoftware Insight Security Research Advisory #NISR03092002B, "Windows .NET
Server (RC1) and MSDE" at
Standards associated with this entry:
BID-5311: Microsoft SQL Server 2000 Resolution Service Stack Overflow
CAN-2002-0649: Multiple buffer overflows in SQL Server 2000 Resolution
Service allow remote attackers to cause a denial of service or execute
arbitrary code via UDP packets to port 1434 in which (1) a 0x04 byte causes
the SQL Monitor thread to generate a long registry key name, or (2) a 0x08
byte with a long string causes heap corruption.
About Internet Security Systems (ISS)
Founded in 1994, Internet Security Systems (ISS) (Nasdaq: ISSX) is a
pioneer and world leader in software and services that protect critical
online resources from an ever-changing spectrum of threats and misuse.
Internet Security Systems is headquartered in Atlanta, GA, with
additional operations throughout the Americas, Asia, Australia, Europe
and the Middle East.
Copyright (c) 2003 Internet Security Systems, Inc. All rights reserved
Permission is hereby granted for the electronic redistribution of this
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medium excluding electronic media, please email for
Disclaimer: The information within this paper may change without notice.
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user's risk. In no event shall the author/distributor (Internet Security
Systems X-Force) be held liable for any damages whatsoever arising out
of or in connection with the use or spread of this information.
X-Force PGP Key available on MIT's PGP key server and PGP.com's key server,
as well as at <http://www.iss.net/security_center/sensitive.php>
Please send suggestions, updates, and comments to: X-Force
of Internet Security Systems, Inc.
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