Sun TCP Connections May Experience Performance Degradation If Certain ICMP Error Messages Are Received

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Impact

This Sun Alert describes the Sun specific impact of the issues described in the Internet-Draft (I-D) titled "ICMP attacks against TCP" written by Fernando Gont. The I-D describes how TCP(7P) connections could be reset and disconnected as a result of ICMP(7P) error messages. Solaris will not drop established TCP connections based on ICMP errors. There is a theoretical possibility that a TCP connection which is in the process of being set up could be terminated before being established. However, there is no risk of data corruption or compromise in this scenario.

The draft also describes ICMP messages which could impact the performance of existing TCP connections. This issue affects all current versions of Solaris and thus Sun plans on improving how ICMP errors are handled to further mitigate the impact of such ICMP messages.

This issue is also described in the following documents:

IETF Internet Draft at http://www.ietf.org/internet-drafts/draft-gont-tcpm-icmp-attacks-03.txt

CERT Vulnerability Note VU#222750 at http://www.kb.cert.org/vuls/id/222750

CVEs CAN-2004-0790 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0790

CVEs CAN-2004-0791 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0791

Contributing Factors

This issue can occur in the following releases:

SPARC Platform

• Solaris 7 without patch 106541-44
• Solaris 8 without patch 116965-19
• Solaris 9 without patch 118305-08
• Solaris 10 without patch 118822-27

x86 Platform

• Solaris 7 without patch 106542-43
• Solaris 8 without patch 116966-18
• Solaris 9 without patch 117470-07
• Solaris 10 without patch 118844-28

Symptoms

In order to verify if ICMP error messages are being sent to a specific system on the network, a network monitoring tool such as snoop(1M) can be used from either the specific system or another system on the same network.

The following command can be run (as "root"):

    # snoop -o <output-file>

Afterwards, the snoop(1M) utility can display the packets captured in the "output-file" using the "-v" and "-i" options, as in:

    # snoop -v -i output-file icmp icmp6

and inspect the output for ICMP packets which will look similar to the following:

    ICMP:  ----- ICMP Header -----
    ICMP:
    ICMP:  Type = 0 (Echo reply)
    ICMP:  Code = 0 (ID: 5417 Sequence number: 0)
    ICMP:  Checksum = be96
    ICMP:

If the "Type" value and the "Code" value (for multiple packets) are equal to any of the following combinations:

    Type    Code    Name                            
    ----    ----    -----------------               
     4       0      Source Quench                  
     3       *      Net/Host/Protocol/Port Unreachable, etc.
     5       *      Redirect                      
     6       0      Alternate Host Address       
     11      *      Time Exceeded  
     12      *      Parameter Problem

then the system may be the target of the described ICMP issue.

Workaround

There is no workaround for this issue. Please see the Resolution section below.

Resolution

This issue is addressed in the following releases:

SPARC Platform

• Solaris 7 with patch 106541-44 or later
• Solaris 8 with patch 116965-19 or later
• Solaris 9 with patch 118305-08 or later
• Solaris 10 with patch 118822-27 or later

x86 Platform

• Solaris 7 with patch 106542-43 or later
• Solaris 8 with patch 116966-18 or later
• Solaris 9 with patch 117470-07 or later
• Solaris 10 with patch 118844-28 or later

Modification History


Date: 07-JUN-2005

Change History:

07-Jun-2005:

• Correction to CERT URL made in Impact section

Date: 02-FEB-2006

02-Feb-2006:

• Updated Contributing Factors and Resolution sections

Date: 03-MAR-2006

03-Mar-2006:

• Updated Contributing Factors and Resolution sections

Date: 21-MAR-2006

21-Mar-2006:

• Updated Contributing Factors and Resolution sections

Date: 12-APR-2006

12-Apr-2006:

• Updated Contributing Factors and Resolution sections

Date: 29-NOV-2006

29-Nov-2006:

• Updated Contributing Factors and Resolution sections

Date: 07-DEC-2006

07-Dec-2006:

• Updated Contributing Factors and Resolution sections
• State: Resolved

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