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Severity
Critical
Title
CS1000 FTP Session Limit Exhaustion
Description

The FTP service on the Nortel Communications Server 1000 (CS1K) on the VGMC and signaling nodes is used to provide firmware updates and basic configuration files to endpoints.


A flaw exists in the session limitation technique employed on the CS1K that can be exploited to cause a denial of service (DoS) to endpoints by preventing them from retrieving firmware updates and basic configuration files.

Details
Category
Denial of Service
Vendor
Nortel
Product
Communications Server 1000 4.50.x
Released
2008-04-01
updated
2008-04-01
Response
Attempting to address the issue
Recommendations

This issue requires a patch from Nortel to completely address.  In the short term it is recommended that a VoIP aware IPS product, such as VoIPguard, with signatures to detect FTP session exhaustion be implemented to prevent it from being exploited or that a session limiting proxy be used.  In addition, implementation of general best practice guidance such as controlling access to telephony networks via VLANs, access control lists, firewalls, network admission controls and/or other security devices will aid in limiting the exposure of this vulnerability.

 

Nortel customers with a valid support agreement may wish to speak with their support contact in order to obtain additional vendor details. 

Tracking Id
VSRNT-2008-001
 

Each line represents an individual vulnerability or group of vulnerabilities. For example, "UCM Multiple Hardcoded Passwords" is presented here in a single line but was reported to Nortel as sixteen (16) individual vulnerabilities.

Severity Legend

Click on a level for description
Low

A low severity issue falls into one of two categories.  Firstly, there are those that are not directly exploitable and affect a single IP client, a small subset of the deployment, or are quite innocuous taken by themselves. In other words, they provide information which either involves only a small number (or single) client and that information requires considerable other information or effort to be useful to an attacker.  The other category of low severity issues includes those that are best practices which are not intended to directly mitigate an exploitable risk but to increase overall security robustness and demonstrate due diligence.

Medium

A medium severity issue is typically an issue which can lead to further exploitation or provides short-lived effect on a minimal number of clients.  It may not be immediately exploitable but provides sufficient information or access to move an attack closer to fruition.  Alternately it may provide unauthorized access not directly related to the VoIP portion of the network.

High

A high severity issue can be exploited to compromise one or more nodes within the deployment but may require authentication, especially when exploiting multiple systems simultaneously. In addition, it may be possible to protect against untrusted exploitation of the issue by deploying traditional security tools.

Critical

A critical severity issue can be exploited by an untrusted individual to compromise the entire deployment under review.  There are no security or protective mechanisms in place that will mediate exploitation of this vulnerability by an untrusted individual.

Vendor Response Legend

Patch available
Workaround proposed
Attempting to address the issue
No vendor response
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