-----BEGIN PGP SIGNED MESSAGE----- 

Security Advisory: Scanning for SSH Can Cause a Crash 

Revision 1.0 

For Public Release 2002 June 27 16:00 (UTC 0000) 

- --------------------------------------------------------------------------- 

Summary 
======= 
While fixing vulnerabilities mentioned in the Cisco Security Advisory: 
Multiple SSH Vulnerabilities (http://www.cisco.com/warp/public/707/ 
SSH-multiple-pub.html) we inadvertently introduced an instability in some 
products. When an attacker tries to exploit the vulnerability VU#945216 
(described in the CERT/CC Vulnerability Note at http://www.kb.cert.org/vuls 
/id/945216) the SSH module will consume too much of the processor's time, 
effectively causing a DoS. In some cases the device will reboot. In order 
to be exposed SSH must be enabled on the device. 

Affected product lines are: 

  * All devices running Cisco IOS® Software supporting SSH. This includes 
    routers and switches running Cisco IOS Software. 
    
  * Catalyst 6000 switches running CatOS. 
    
  * Cisco PIX Firewall. 
    
  * Cisco 11000 Content Service Switch family. 

No other Cisco product is vulnerable. It is possible to mitigate this 
vulnerability by preventing, or having control over, the SSH traffic. 

This advisory is available at http://www.cisco.com/warp/public/707/ 
SSH-scanning.shtml. 

Affected Products 
================= 
  * All devices running Cisco IOS Software supporting SSH. This includes 
    routers and switches running Cisco IOS Software. 
    
  * Catalyst 6000 switches running CatOS. 
    
  * Cisco PIX Firewall. 
    
  * Cisco 11000 Content Service Switch family. 

+--------------------------------------------------+ 
| Product Category | Vulnerability ID | 
|--------------------+-----------------------------| 
| IOS | CSCdw33027 | 
|--------------------+-----------------------------| 
| PIX | CSCdw29965 | 
|--------------------+-----------------------------| 
| VPN 3000 | Not affected | 
|--------------------+-----------------------------| 
| Catalyst 6000 | CSCdv85279 and CSCdw59394 | 
|--------------------+-----------------------------| 
| CSS 11000 | CSCdx59197 | 
+--------------------------------------------------+ 

All software releases listed in the http://www.cisco.com/warp/public/707/ 
SSH-multiple-pub.html (Cisco Security Advisory: Multiple SSH 
Vulnerabilities), including all subsequent software releases that contain 
the patches addressed by that advisory are vulnerable. 

All software that does not contain fixes for the issues listed in the 
previous SSH advisory are not vulnerable to the issue described in this 
advisory. However, falling back to a previous software release will leave 
you exposed to the vulnerabilities described in the previous advisory and 
you will lose any additional features or functionalities introduced in the 
newer releases. 

No other Cisco products are affected. 

Details 
======= 
While fixing the vulnerabilities listed in http://www.cisco.com/warp/public 
/707/SSH-multiple-pub.html (Cisco Security Advisory: Multiple SSH 
Vulnerabilities) an instability is introduced in some products. When 
exposed to an overly large packet, the SSH process will consume a large 
portion of the processor's instruction cycles, effectively causing a DoS. 
The capability to create such a packet is available in publicly available 
exploit code. In some cases this availability attack may result in a reboot 
of the device. In order to be exposed SSH must be enabled on the device. 

The vulnerability in question is named CRC-32 Check in the http:// 
www.cisco.com/warp/public/707/SSH-multiple-pub.html. It is also marked as 
VU#945216 and described in the CERT/CC Vulnerability Note at http:// 
www.kb.cert.org/vuls/id/945216. 

Impact 
====== 
By repeatedly exploiting this vulnerability an attacker can cause a denial 
of service, though Cisco products remain unaffected to the exploits that 
are trying to exploit vulnerabilities listed in http://www.cisco.com/warp/ 
public/707/SSH-multiple-pub.html. 

Software Versions and Fixes 
=========================== 
For CSS 11000 family, the vulnerability is fixed in the following software 
releases. 

+--------------------------------------------------+ 
| WebNS | R5.00.045 or later (available now) | 
| | 5.10.1.01 available July 2002 | 
+--------------------------------------------------+ 

For Catalyst 6000 switches, the vulnerability is fixed in the following 
CatOS releases. This table lists the first fixed release. 

+--------------------------------------------------+ 
| CatOS | 6.3(3.6), 7.1(0.94), 7.2(0.14)PEN | 
+--------------------------------------------------+ 

Each row of the table describes a release train and the platforms or 
products for which it is intended. If a given release train is vulnerable, 
then the earliest possible releases that contain the fix and the 
anticipated date of availability for each are listed in the "Rebuild", 
"Interim", and "Maintenance" columns. A device running any release in the 
given train that is earlier than the release in a specific column (less 
than the earliest fixed release) is known to be vulnerable, and it should 
be upgraded at least to the indicated release or a later version (greater 
than the earliest fixed release label). 

When selecting a release, keep in mind the following definitions: 

    Maintenance 
        Most heavily tested and highly recommended release of any label in 
        a given row of the table. 
        
    Rebuild 
        Constructed from the previous maintenance or major release in the 
        same train, it contains the fix for a specific defect. Although it 
        receives less testing, it contains only the minimal changes 
        necessary to effect the repair. 
        
    Interim 
        Built at regular intervals between maintenance releases and 
        receives less testing. Interims should be selected only if there is 
        no other suitable release that addresses the vulnerability. Interim 
        images should be upgraded to the next available maintenance release 
        as soon as possible. Interim releases are not available through 
        manufacturing, and usually they are not available for customer 
        download from CCO without prior arrangement with the Cisco 
        Technical Assistance Center (TAC). 
        
In all cases, customers should exercise caution to be certain the devices 
to be upgraded contain sufficient memory and that current hardware and 
software configurations will continue to be supported properly by the new 
release. If the information is not clear, contact the Cisco TAC for 
assistance as shown in the following section. 

More information on Cisco IOS software release names and abbreviations is 
available at http://www.cisco.com/warp/public/620/1.html. 

For PIX Firewall software, use the following table to determine affected 
and fixed software releases. 

+---------------------------------------------------------+ 
| | Description | | 
| Train | of Image or | Availability of Fixed Releases* | 
| | Platform | | 
|---------------------+-----------------------------------| 
| 5.x-based Releases | Rebuild | Interim** | Maintenance | 
|---------------------+---------+-----------+-------------| 
| | General | | | | 
| | Deployment | | | | 
| | (GD) for | | 5.2(6)202 | | 
| 5.2 | Classic, | | Available | 5.2(7) | 
| | 10000, 506, | | through | | 
| | 506E, 510, | | TAC | | 
| | 515, 515E, | | | | 
| | 520 and 525 | | | | 
|-------+-------------+---------+-----------+-------------| 
| | Early | | | | 
| | Deployment | | | | 
| | (ED) for | | 5.3(2)205 | | 
| | Classic, | | Available | | 
| 5.3 | 10000, 506, | | through | 5.3(3) | 
| | 506E, 510, | | TAC | | 
| | 515, 515E, | | | | 
| | 520, 525 | | | | 
| | and 535 | | | | 
|---------------------+---------+-----------+-------------| 
| 6.x-based Releases | Rebuild | Interim** | Maintenance | 
|---------------------+---------+-----------+-------------| 
| | Early | | | | 
| | Deployment | | 6.0(1)106 | | 
| | (ED) for | | Available | | 
| 6.0 | 501, 506, | | through | 6.0(2) | 
| | 506E, 515, | | TAC | | 
| | 515E, 520, | | | | 
| | 525 and 535 | | | | 
|-------+-------------+---------+-----------+-------------| 
| | Early | | | | 
| | Deployment | | 6.1(1)105 | | 
| | (ED) for | | Available | | 
| 6.1 | 501, 506, | | through | 6.1(2) | 
| | 506E, 515, | | TAC | | 
| | 515E, 520, | | | | 
| | 525 and 535 | | | | 
|-------+-------------+---------+-----------+-------------| 
| | Early | | | | 
| | Deployment | | 6.2(0)222 | | 
| | (ED) for | | Available | | 
| 6.2 | 501, 506, | | through | 6.2(1) | 
| | 506E, 515, | | TAC | | 
| | 515E, 520, | | | | 
| | 525 and 535 | | | | 
+---------------------------------------------------------+ 

For Cisco IOS software, use the following table to determine affected and 
fixed software releases. This table always lists the first fixed release, 
which is not necessarily the recommended release for your particular 
environment. 

+-----------------------------------------------------------------------+ 
| Train | Description of Image | Availability of Fixed Releases* | 
| | or Platform | | 
|--------------------------------+--------------------------------------| 
| 12.0-based Releases | Rebuild | Interim | Maintenance | 
| | | ** | | 
|--------------------------------+------------+---------+---------------| 
| 12.0S | Core/ISP support: | 12.0(17)S4 | 12.0 | 12.0(21)S | 
| | GSR, RSP, c7200 | | (20.4)S | | 
|--------+-----------------------+------------+---------+---------------| 
| | Core/ISP support: | 12.0(20) | 12.0 | | 
| 12.0SP | GSR, RSP, c7200 | SP2 | (20.4) | | 
| | | | SP | | 
|--------+-----------------------+------------+---------+---------------| 
| | Core/ISP support: | 12.0(17) | 12.0 | | 
| 12.0ST | GSR, RSP, c7200 | ST5 | (20.3) | 12.0(21)S | 
| | | | ST2 | | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.0XB |Release |--------------------------------------| 
| | | Migrate to 12.1(1)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.0XM |Release |--------------------------------------| 
| | | Migrate to 12.1(3)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.0XV |Release |--------------------------------------| 
| | | Migrate to 12.1(2)T or later | 
|--------------------------------+--------------------------------------| 
| 12.1-based Releases | Rebuild | Interim | Maintenance | 
| | | ** | | 
|--------------------------------+--------------------------------------| 
| | General deployment | | 
| 12.1 | release for all | SSH not supported | 
| | platforms | | 
|--------+-----------------------+--------------------------------------| 
| | Core/ISP support: | | 12.1 | | 
| 12.1E | GSR, RSP, c7200, | 12.1(8b)E8 | (10.5)E | 12.1(11b)E | 
| | Catalyst 6000 | | | | 
|--------+-----------------------+------------+---------+---------------| 
| | Early Deployment | | 12.1 | | 
| 12.1EC | Release | | (10.5) | 12.1(12c)EC | 
| | | | EC | | 
|--------+-----------------------+--------------------------------------| 
| 12.1 | Early Deployment | Not Scheduled | 
| (1)EX |Release |--------------------------------------| 
| | | Migrate to 12.1(3)T or later | 
|--------+-----------------------+--------------------------------------| 
| 12.1 | | Not Scheduled | 
| (5c)EX |Catalyst 6000 support |--------------------------------------| 
| | | Migrate to 12.1(6)EX or later | 
|--------+-----------------------+--------------------------------------| 
| 12.1 | | Not Scheduled | 
| (8a)EX |12.1E based XED |--------------------------------------| 
| | | Migrate to 12.1(11)E or later | 
|--------+-----------------------+--------------------------------------| 
| 12.1 | Early Deployment | Not Scheduled | 
| (9)EX |Release |--------------------------------------| 
| | | Migrate to 12.1(10)EX or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment(ED): | Not Scheduled | 
| | VPN, Distributed | | 
| 12.1T |Director, various |--------------------------------------| 
| | platforms | Migrate to 12.2 or later | 
| | | | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XB |Release |--------------------------------------| 
| | | Migrate to 12.1(5)YB or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XC |(ED): limited |--------------------------------------| 
| | platforms | Migrate to 12.2 or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | 12.1(2)XF6 | | Not planned, | 
| 12.1XF | (ED): 811 and 813 | Release | | migrate to | 
| | (c800 images) | date to be | | 12.1(5)T or | 
| | | determined | | later | 
|--------+-----------------------+------------+---------+---------------| 
| | Early Deployment | 12.1(3)XG7 | | Not planned, | 
| 12.1XG | (ED): 800, 805, 820, | Release | | migrate to | 
| | and 1600 | date to be | | 12.2(1)T or | 
| | | determined | | later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XH |(ED): limited |--------------------------------------| 
| | platforms | Migrate to 12.2 or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XI |(ED): limited |--------------------------------------| 
| | platforms | Migrate to 12.2 or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XJ |(ED): limited |--------------------------------------| 
| | platforms | Migrate to 12.2(2)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XL |(ED): limited |--------------------------------------| 
| | platforms | Migrate to 12.2 or later | 
|--------+-----------------------+--------------------------------------| 
| | | | | Not planned, | 
| 12.1XM | Short-lived early | 12.1(5)XM7 | | migrate to | 
| | deployment release | | | 12.2(1)T or | 
| | | | | later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.1XP |deployment release |--------------------------------------| 
| | | Migrate to 12.2(2)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.1XQ |deployment release |--------------------------------------| 
| | | Migrate to 12.2(2)XB or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XT |(ED): 1700 series |--------------------------------------| 
| | | Migrate to 12.2(2)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.1XU |(ED): limited |--------------------------------------| 
| | platforms | Migrate to 12.2T or later | 
|--------+-----------------------+--------------------------------------| 
| | | 12.1(5)YB6 | | Not planned, | 
| 12.1YB | Short-lived early | Release | | migrate to | 
| | deployment release | date to be | | 12.2(2)T or | 
| | | determined | | later | 
|--------+-----------------------+------------+---------+---------------| 
| | | 12.1(5)YC3 | | Not planned, | 
| 12.1YC | Short-lived early | Release | | migrate to | 
| | deployment release | date to be | | 12.2(4)T or | 
| | | determined | | later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.1YD |deployment release |--------------------------------------| 
| | | Migrate to 12.2(8)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.1YE |deployment release |--------------------------------------| 
| | | Migrate to 12.1(5)YI or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.1YF |deployment release |--------------------------------------| 
| | | Migrate to 12.2(2)XN or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.1YI |deployment release |--------------------------------------| 
| | | Migrate to 12.2(2)YC or later | 
|--------------------------------+--------------------------------------| 
| 12.2-based Releases | Rebuild | Interim | Maintenance | 
| | | ** | | 
|--------------------------------+------------+---------+---------------| 
| | General deployment | | 12.2 | | 
| 12.2 | release for all | 12.2(6b) | (7.4) | 12.2(7) | 
| | platforms | | | | 
|--------+-----------------------+------------+---------+---------------| 
| 12.2B | Early Deployment | 12.2(4)B3 | 12.2 | | 
| | Broadband Release | | (7.6)B | | 
|--------+-----------------------+------------+---------+---------------| 
| | Early Deployment | | | | 
| 12.2BC | Broadband Release | 12.2(8)BC1 | | | 
| | uBR7000 and uBR10000 | | | | 
|--------+-----------------------+------------+---------+---------------| 
| 12.2DA | Early Deployment | 12.2(6.8a) | | 12.2(7)DA | 
| | Release: xDSL | DA | | | 
|--------+-----------------------+--------------------------------------| 
| | Specific Technology | Not Scheduled | 
| 12.2DD |Early Deployment |--------------------------------------| 
| | release for 7200 and | Migrate to 12.2(4)B1 or later | 
|--------+-----------------------+--------------------------------------| 
| 12.2S | SPLOB | | 12.2 | | 
| | | | (7.4)S | | 
|--------+-----------------------+------------+---------+---------------| 
| | General deployment | | 12.2 | | 
| 12.2T | release for all | | (7.4)T | 12.2(8)T | 
| | platforms | | | | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.2XA |Release |--------------------------------------| 
| | | Migrate to 12.2(4)T or 12.2(2)XB | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | 12.2(2)XB4 | | | 
| 12.2XB | Release | Available | | | 
| | | 2002-July | | | 
|--------+-----------------------+------------+---------+---------------| 
| | | | | Not planned, | 
| 12.2XD | ICS7750, 820, soho70 | 12.2(1)XD4 | | migrate to | 
| | | | | 12.2(8)T or | 
| | | | | later | 
|--------+-----------------------+------------+---------+---------------| 
| | | | | Not planned, | 
| 12.2XE | 806, 820, soho78 | 12.2(1)XE3 | | migrate to | 
| | | | | 12.2(8)T or | 
| | | | | later | 
|--------+-----------------------+--------------------------------------| 
| | DOCSYS support, | Not Scheduled | 
| 12.2XF |uBR7100, uBR7200, |--------------------------------------| 
| | uBR10000 | Migrate to 12.2(4)BC1 | 
|--------+-----------------------+--------------------------------------| 
| | | Not Scheduled | 
| 12.2XG |IAD2400/2600/3600 |--------------------------------------| 
| | | Migrate to 12.2(8)T | 
|--------+-----------------------+--------------------------------------| 
| | 1700, 800, 820, | | | Not planned, | 
| 12.2XH | soho70 | 12.2(2)XH3 | | migrate to | 
| | | | | 12.2(8)T | 
|--------+-----------------------+------------+---------+---------------| 
| | Early Deployment | | | Not planned, | 
| 12.2XI | Release 820/SOHO | 12.2(2)XI2 | | migrate to | 
| | | | | 12.2(12)T | 
|--------+-----------------------+--------------------------------------| 
| | | Not Scheduled | 
| 12.2XJ |1700 |--------------------------------------| 
| | | Migrate to 12.2(4)YB | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | | | Not planned, | 
| 12.2XK | Release 820/SOHO | 12.2(2)XK3 | | migrate to | 
| | | | | 12.2(12)T | 
|--------+-----------------------+------------+---------+---------------| 
| | 1700, 820, 800, | 12.2(4)XL5 | | Not planned, | 
| 12.2XL | SOHO70 | Available | | migrate to | 
| | | 2002-June | | 12.2(12)T | 
|--------+-----------------------+------------+---------+---------------| 
| 12.2XM | Early Deployment | 12.2(4)XM4 | | | 
| | Release | | | | 
|--------+-----------------------+--------------------------------------| 
| | Early Deployment | Not Scheduled | 
| 12.2XN |Release for enhanced |--------------------------------------| 
| | MGCP support, | Upgrade recommended to a release yet | 
| | selected platforms | to be determined | 
|--------+-----------------------+--------------------------------------| 
| | | Not Scheduled | 
| 12.2XQ |1720, 1750, 1752 |--------------------------------------| 
| | | Migrate to 12.2(4)YB or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.2XR |deployment release |--------------------------------------| 
| | | Migrate to 12.2(4)XR or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.2XS |deployment release |--------------------------------------| 
| | | Migrate to 12.2(6) or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.2XT |deployment release |--------------------------------------| 
| | | Migrate to 12.2(8)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.2XW |deployment release |--------------------------------------| 
| | | Migrate to 12.2(4)YB or later | 
|--------+-----------------------+--------------------------------------| 
| 12.2YA | Early Deployment | 12.2(4)YA2 | | | 
| | Release | | | | 
|--------+-----------------------+--------------------------------------| 
| | | Not Scheduled | 
| 12.2YB |Short-lived early |--------------------------------------| 
| | deployment release | Upgrade recommended to yet to be | 
| | | determined release | 
|--------+-----------------------+--------------------------------------| 
| | Short-lived early | Not Scheduled | 
| 12.2YC |deployment release |--------------------------------------| 
| | | Migrate to 12.2(13)T or later | 
|--------+-----------------------+--------------------------------------| 
| | Broadband suport for | Not Scheduled | 
| 12.2YD |7200 |--------------------------------------| 
| | | Migrate to 12.2(8)B or later | 
|--------+-----------------------+--------------------------------------| 
| | | Not Scheduled | 
| 12.2YF |Short-lived early |--------------------------------------| 
| | deployment release | Upgrade recommended to yet to be | 
| | | determined release | 
|--------+-----------------------+--------------------------------------| 
| 12.2YG | Early Deployment | | | 12.2(4)YG | 
| | Release | | | | 
|--------+-----------------------+------------+---------+---------------| 
| 12.2YH | 1700, 8xx, soho7x, | | | 12.2(4)YH | 
| | ICS7700 | | | | 
|-----------------------------------------------------------------------| 
| Notes | 
|-----------------------------------------------------------------------| 
| * All dates are estimates and subject to change. | 
| | 
| ** Interim releases are subjected to less rigorous testing than | 
| regular maintenance releases, and may have serious bugs. | 
+-----------------------------------------------------------------------+ 

Obtaining Fixed Software 
======================== 
Cisco is offering free software upgrades to remedy this vulnerability for 
all affected customers. Customers may only install and expect support for 
the feature sets they have purchased. 

Customers with service contracts should obtain upgraded software through 
their regular update channels to any software release containing the 
feature sets they have purchased. For most customers, this means that 
upgrades should be obtained through the Software Center on Cisco's 
worldwide website at http://www.cisco.com. 

Customers whose Cisco products are provided or maintained through prior or 
existing agreement with third-party support organizations such as Cisco 
Partners, authorized resellers, or service providers should contact that 
support organization for assistance with the upgrade, which should be free 
of charge. 

Customers who purchased directly from Cisco but who do not hold a Cisco 
service contract, and customers who purchase through third party vendors 
but are unsuccessful at obtaining fixed software through their point of 
sale, should obtain fixed software by contacting the Cisco Technical 
Assistance Center (TAC). In those cases, customers may only upgrade to a 
later version of the same release as indicated by the applicable row in the 
Software Versions and Fixes table. 

Cisco TAC contacts are as follows: 

  * +1 800 553 2447 (toll-free from within North America) 
  * +1 408 526 7209 (toll call from anywhere in the world) 
  * e-mail: tac@cisco.com 

See http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for 
additional TAC contact information, including special localized telephone 
numbers and instructions and e-mail addresses for use in various languages. 

Please have your product serial number available and give the URL of this 
notice as evidence of your entitlement to a free upgrade. Free upgrades for 
non-contract customers must be requested through the TAC. 

Please do not contact either "psirt@cisco.com" or 
"security-alert@cisco.com" for software upgrades. 

Workarounds 
=========== 
It is possible to mitigate this vulnerability in two ways: 

  * Block all SSH connections on the border on your network, or 
    
  * On each individual device allow SSH connections only from the required 
    IP addresses and block all others. 

Blocking all SSH connections, and all other protocols that are not supposed 
to come from the outside, on the network edge should be an integral part of 
the network security best practice. 

Exploitation and Public Announcements 
===================================== 
Publicly available malicous software is known to trigger this defect. 
Scanning for Unix hosts running vulnerable versions of SSH has been 
prevalent and such a scan may trigger this vulnerability. 

Cisco PSIRT is aware of a few customers who experienced problems related 
to this vulnerability, however we do not have any evidence that these 
devices were targeted directly. 

Status of This Notice: FINAL 
============================ 
This is a final notice. Although Cisco cannot guarantee the accuracy of all 
statements in this notice, all of the facts have been checked to the best 
of our ability. Cisco does not anticipate issuing updated versions of this 
notice unless there is some material change in the facts. Should there be a 
significant change in the facts, Cisco may update this notice. 

A standalone copy or paraphrase of the text of this security advisory that 
omits the distribution URL in the following section is an uncontrolled 
copy, and may lack important information or contain factual errors. 

Distribution 
============ 
This notice will be posted on Cisco's worldwide web site at http:// 
www.cisco.com/warp/public/707/SSH-scanning.shtml. In addition to worldwide 
web posting, a text version of this notice is clear-signed with the Cisco 
PSIRT PGP key and is posted to the following e-mail and Usenet news 
recipients: 

  * cust-security-announce@cisco.com 
  * bugtraq@securityfocus.com 
  * first-teams@first.org (includes CERT/CC) 
  * cisco@spot.colorado.edu 
  * comp.dcom.sys.cisco 
  * firewalls@lists.gnac.com 
  * Various internal Cisco mailing lists 

Future updates of this notice, if any, will be placed on Cisco's worldwide 
web server, but may or may not be actively announced on mailing lists or 
newsgroups. Users concerned about this problem are encouraged to check the 
URL given above for any updates. 

Revision History 
================ 
+----------------------------------------------------------------------+ 
|Revision |2002-June-27|Initial public release | 
|1.0 |14:18 | | 
| |GMT+0000 | | 
+----------------------------------------------------------------------+ 

Cisco Security Procedures 
========================= 
Complete information on reporting security vulnerabilities in Cisco 
products, obtaining assistance with security incidents, and registering to 
receive security information from Cisco, is available on Cisco's worldwide 
website at http://www.cisco.com/warp/public/707/sec_incident_response.shtml 
This includes instructions for press inquiries regarding Cisco security 
notices. 

All Cisco Security Advisories are available at 
http:// www.cisco.com/go/psirt. 

- --------------------------------------------------------------------------- 

This notice is Copyright 2002 by Cisco Systems, Inc. This notice may be 
redistributed freely after the release date given at the top of the text, 
provided that redistributed copies are complete and unmodified, and include 
all date and version information. 

- --------------------------------------------------------------------------- 

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