Severity rating


Discovered date

Attack vector

Authentication required

Public exploits available

Signature detection

On this page


A buffer overrun vulnerability exists in LSASS that could allow remote code execution on an affected system.


An attacker who successfully exploited this vulnerability could take complete control of the affected system.

Technical details (analysis)

Local Security Authority Subsystem Service (LSASS) provides an interface for managing local security, domain authentication, and Active Directory processes. It handles authentication for the client and for the server. It also contains features that are used to support Active Directory utilities. An unchecked buffer exists in the LSASS service, which allows a stacked based buffer over run in an active directory function of the Local Security Authority Subsystem Service. A crafted RPC over TPC or named pipe request could exploit this vulnerability.

Affected software

Microsoft Windows NT Workstation 4.0 Service Pack 6a
Microsoft Windows NT Server 4.0 Service Pack 6a
Microsoft Windows NT Server 4.0 Terminal Server Edition Service Pack 6
Microsoft Windows 2000 Service Pack 2, Microsoft Windows 2000 Service Pack 3, and Microsoft
Windows 2000 Service Pack 4
Microsoft Windows XP and Microsoft Windows XP Service Pack 1
Microsoft Windows XP 64-Bit Edition Service Pack 1
Microsoft Windows XP 64-Bit Edition Version 2003
Microsoft Windows Server 2003
Microsoft Windows Server 2003 64-Bit Edition
Microsoft NetMeeting
Microsoft Windows 98, Microsoft Windows 98 Second Edition (SE), and Microsoft Windows Millennium Edition (ME) � Review the FAQ section of this bulletin for details about these operating systems.

Non-affected software

All those not on the affected applications list.



NIS signature

Name: Vulnerability:Win/MSRPC.LSASS.RCE!CAN-2003-0533
Release Date: 2004-04-13T00:00:00

Known false positives

No known false positives at this time.


Use a personal firewall such as the Internet Connection Firewall, which is included with Windows XP and Windows Server 2003.
Block the following at the firewall: UDP ports 135, 137, 138, and 445, and TCP ports 135, 139, 445, and 593. All unsolicited inbound traffic on ports greater than 1024. Any other specifically configured RPC port.
Enable advanced TCP/IP filtering on systems that support this feature.
Block the affected ports by using IPSec on the affected systems.