NT CSRSS Worker Thread Exhaustion Vulnerability

BID:478

Info

NT CSRSS Worker Thread Exhaustion Vulnerability

Bugtraq ID: 478
Class: Design Error
CVE:
Remote: No
Local: Yes
Published: Apr 09 1999 12:00AM
Updated: Apr 09 1999 12:00AM
Credit: Jeff Sumner <[email protected]> discovered this vulnerability and posted it to the newsgroup microsoft.public.win32.programmer.kernel on April 9, 1999.
Vulnerable: Microsoft Windows NT 4.0 SP5
+ Microsoft Windows NT Enterprise Server 4.0 SP5
+ Microsoft Windows NT Enterprise Server 4.0 SP5
+ Microsoft Windows NT Server 4.0 SP5
+ Microsoft Windows NT Server 4.0 SP5
+ Microsoft Windows NT Terminal Server 4.0 SP5
+ Microsoft Windows NT Terminal Server 4.0 SP5
+ Microsoft Windows NT Workstation 4.0 SP5
+ Microsoft Windows NT Workstation 4.0 SP5
Microsoft Windows NT 4.0 SP4
+ Microsoft Windows NT Enterprise Server 4.0 SP4
+ Microsoft Windows NT Enterprise Server 4.0 SP4
+ Microsoft Windows NT Server 4.0 SP4
+ Microsoft Windows NT Server 4.0 SP4
+ Microsoft Windows NT Terminal Server 4.0 SP4
+ Microsoft Windows NT Terminal Server 4.0 SP4
+ Microsoft Windows NT Workstation 4.0 SP4
+ Microsoft Windows NT Workstation 4.0 SP4
Microsoft Windows NT 4.0 SP3
+ Microsoft Windows NT Enterprise Server 4.0 SP3
+ Microsoft Windows NT Enterprise Server 4.0 SP3
+ Microsoft Windows NT Server 4.0 SP3
+ Microsoft Windows NT Server 4.0 SP3
+ Microsoft Windows NT Terminal Server 4.0 SP3
+ Microsoft Windows NT Terminal Server 4.0 SP3
+ Microsoft Windows NT Workstation 4.0 SP3
+ Microsoft Windows NT Workstation 4.0 SP3
Microsoft Windows NT 4.0 SP2
+ Microsoft Windows NT Enterprise Server 4.0 SP2
+ Microsoft Windows NT Enterprise Server 4.0 SP2
+ Microsoft Windows NT Server 4.0 SP2
+ Microsoft Windows NT Server 4.0 SP2
+ Microsoft Windows NT Terminal Server 4.0 SP2
+ Microsoft Windows NT Terminal Server 4.0 SP2
+ Microsoft Windows NT Workstation 4.0 SP2
+ Microsoft Windows NT Workstation 4.0 SP2
Microsoft Windows NT 4.0 SP1
+ Microsoft Windows NT Enterprise Server 4.0 SP1
+ Microsoft Windows NT Enterprise Server 4.0 SP1
+ Microsoft Windows NT Server 4.0 SP1
+ Microsoft Windows NT Server 4.0 SP1
+ Microsoft Windows NT Terminal Server 4.0 SP1
+ Microsoft Windows NT Terminal Server 4.0 SP1
+ Microsoft Windows NT Workstation 4.0 SP1
+ Microsoft Windows NT Workstation 4.0 SP1
Microsoft Windows NT 4.0
+ Microsoft Windows NT Enterprise Server 4.0
+ Microsoft Windows NT Enterprise Server 4.0
+ Microsoft Windows NT Server 4.0
+ Microsoft Windows NT Server 4.0
+ Microsoft Windows NT Terminal Server 4.0
+ Microsoft Windows NT Terminal Server 4.0
+ Microsoft Windows NT Workstation 4.0
+ Microsoft Windows NT Workstation 4.0
Not Vulnerable: Microsoft Windows NT 3.5.1 SP5
Microsoft Windows NT 3.5.1 SP4
Microsoft Windows NT 3.5.1 SP3
Microsoft Windows NT 3.5.1 SP2
Microsoft Windows NT 3.5.1 SP1
Microsoft Windows NT 3.5.1
Microsoft Windows NT 3.5

Discussion

NT CSRSS Worker Thread Exhaustion Vulnerability

Worker threads in CSRSS.exe (the Client Server Runtime SubSystem, aka the Win32 Subsystem) that are waiting for user input remain occupied until they get that input. If all threads (default 16) are simultaneously waiting for input, the system will hang until it is received. This condition will lead to a Denial of Service, and could be caused by malicious or defective code in a service or program.

Exploit / POC

NT CSRSS Worker Thread Exhaustion Vulnerability

Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected].

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