Microsoft Windows NT CSRSS denial of service
|nt-csrss-dos (2299)||Medium Risk|
The Microsoft Windows NT CSRSS.EXE Client Server Runtime Subsystem service is vulnerable to a denial of service attack against hosts accepting interactive logins. CSRSS provides Windows NT services to client processes running on the local computer.
When all worker threads (by default, a maximum of 16) within the CSRSS service are awaiting user input, no new connections can be made, effectively hanging the system.
Denial of Service
Apply the latest Windows NT 4.0 Service Pack (SP6a or later), available from the Windows NT Service Packs Web page. See References.
— OR —
As an alternative, Windows NT SP5 users can apply the post-SP5 Csrss-fix patch, as listed in Microsoft Security Bulletin MS99-021. See References.
- CIAC Information Bulletin J-049: Windows NT, Two Denial-of-Service Vulnerabilities (Malformed LSA Request and CSRSS Worker Thread Exhaustion).
- Microsoft Knowledge Base Article 233323: Exceeding MaxRequestThreads may Cause Windows NT to Hang.
- Microsoft Product Support Services: Windows NT Service Packs.
- Microsoft Security Bulletin MS99-021: Patch Available for 'CSRSS Worker Thread Exhaustion' Vulnerability.
- BID-478: NT CSRSS Worker Thread Exhaustion Vulnerability
- CVE-1999-0723: The Windows NT Client Server Runtime Subsystem (CSRSS) can be subjected to a denial of service when all worker threads are waiting for user input.
- OSVDB ID: 11474: Microsoft Windows NT CSRSS Thread Exhaustion DoS
- Microsoft Windows 2000
- Microsoft Windows NT 4.0
Jun 23, 1999
The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall the author/distributor (IBM 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.
For corrections or additions please email ignore thisxforceignore this@ignore thisus.ignore thisibm.comignore this