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CERT Coordination Center

NetScreen Secure Command Shell (SCS) denial-of-service vulnerability

Vulnerability Note VU#930161

Original Release Date: 2002-11-19 | Last Revised: 2002-12-10


The Secure Command Shell service on NetScreen firewall products contains a remotely exploitable denial-of-service vulnerability.


Firewall products from NetScreen Technologies, Inc. include a Secure Shell version 1 (SSHv1) implementation called Secure Command Shell (SCS). The SCS service contains a remotely exploitable denial-of-service vulnerability which can cause affected units to crash. According to the original reporter, programs which attempt to exploit VU#945216 trigger the vulnerability and cause the unit to crash. NetScreen has confirmed this, but has stated that this vulnerability is not the same as VU#945216.


A remote attacker can cause the affected unit to crash. The original reporter indicates that the system may subsequently require a hard reboot.


NetScreen has issued a patch for this vulnerability. Information about it can be found at


If patches cannot be applied, NetScreen recommends disabling the SCS service on affected systems. Note that according to NetScreen the SCS service is not enabled by default.
If the service cannot be disabled, limit access to the SSH service to only trusted hosts on the internal network.

Vendor Information


NetScreen Affected

Notified:  November 07, 2002 Updated: November 14, 2002



Vendor Statement

NetScreen has posted a security alert notice in response to this. You can find our response by going to

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

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Thanks to Erik Parker of DigitalDefense for reporting this vulnerability.

This document was written by Chad R Dougherty.

Other Information

CVE IDs: None
Severity Metric: 5.40
Date Public: 2002-11-01
Date First Published: 2002-11-19
Date Last Updated: 2002-12-10 21:16 UTC
Document Revision: 14

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