NT LSA DoS (Phantom) Vulnerability
BID:465
Info
NT LSA DoS (Phantom) Vulnerability
| Bugtraq ID: | 465 |
| Class: | Failure to Handle Exceptional Conditions |
| CVE: | |
| Remote: | Yes |
| Local: | No |
| Published: | Jun 23 1999 12:00AM |
| Updated: | Jun 23 1999 12:00AM |
| Credit: | This vulnerability was identified by Bindview Development Corporation and was reported to Bugtraq by Adam Shostack <[email protected]>. |
| Vulnerable: |
Microsoft Windows NT 4.0 SP5 Microsoft Windows NT 4.0 SP4 Microsoft Windows NT 4.0 SP3 Microsoft Windows NT 4.0 SP2 Microsoft Windows NT 4.0 SP1 Microsoft Windows NT 4.0 |
| Not Vulnerable: | |
Discussion
NT LSA DoS (Phantom) Vulnerability
NT hosts are subject to a Denial of Service attack against the Local Security Authority (LSA) subsystem. The LSA system, as well as the Security Accounts Manager and certain MSRPC processes can be crashed by sending invalid data to the LsaLookupNames function of the LSA API.
In order for this exploit to occur, the user must first establish a null session connection to the target host.
Once a host has been impacted by this exploit, the NT system will begin to exhibit "strange behavior". Remote users will be unable to connect to the host's shares or resources, users may not be able to change their passwords, console logon to a domain will be unavailable, systems management tools such as User Manager and Server Manager will not function, and RPC dependant services using integrated security (IIS, SQL Server) will not function. Users will be unable to shutdown the server - they will receive a message stating that the current user does not have privileges to perform that function. Users connected to resources prior to the attack will still be able to access these resources.
These symptoms can be delayed by disabling the automatic debug option in the Registry. To disable this, set the "Auto" value of the HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug key to "0". In this configuration, the debugger will prompt the user to continue. The symptoms of the attack will not appear until this dialog box has been cleared.
This Denial of Service attack requires the machine to be "hard-booted" to reset the system to normal operation. Upon reboot, the system will function normally.
NT hosts are subject to a Denial of Service attack against the Local Security Authority (LSA) subsystem. The LSA system, as well as the Security Accounts Manager and certain MSRPC processes can be crashed by sending invalid data to the LsaLookupNames function of the LSA API.
In order for this exploit to occur, the user must first establish a null session connection to the target host.
Once a host has been impacted by this exploit, the NT system will begin to exhibit "strange behavior". Remote users will be unable to connect to the host's shares or resources, users may not be able to change their passwords, console logon to a domain will be unavailable, systems management tools such as User Manager and Server Manager will not function, and RPC dependant services using integrated security (IIS, SQL Server) will not function. Users will be unable to shutdown the server - they will receive a message stating that the current user does not have privileges to perform that function. Users connected to resources prior to the attack will still be able to access these resources.
These symptoms can be delayed by disabling the automatic debug option in the Registry. To disable this, set the "Auto" value of the HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug key to "0". In this configuration, the debugger will prompt the user to continue. The symptoms of the attack will not appear until this dialog box has been cleared.
This Denial of Service attack requires the machine to be "hard-booted" to reset the system to normal operation. Upon reboot, the system will function normally.
Exploit / POC
NT LSA DoS (Phantom) 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].
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].
Solution / Fix
NT LSA DoS (Phantom) Vulnerability
Solution:
Microsoft has issued a Post Service Pack 5 hotfix to correct this vulnerability. This hotfix can be downloaded at: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes-postSP5/LSA3-fix/
Solution:
Microsoft has issued a Post Service Pack 5 hotfix to correct this vulnerability. This hotfix can be downloaded at: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes-postSP5/LSA3-fix/
References
NT LSA DoS (Phantom) Vulnerability
References:
References: