Cisco Security Advisory

IOS HTTP Server Command Injection Vulnerability

Advisory ID: cisco-sa-20051201-http

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20051201-http

Revision 2.0

For Public Release 2005 December 1 21:00  UTC (GMT)


Summary

A vulnerability exists in the IOS HTTP server in which HTML code inserted into dynamically generated output, such as the output from a show buffers command, will be passed to the browser requesting the page. This HTML code could be interpreted by the client browser and potentially execute malicious commands against the device or other possible cross-site scripting attacks. Successful exploitation of this vulnerability requires that a user browse a page containing dynamic content in which HTML commands have been injected.

Cisco will be making free software available to address this vulnerability for affected customers. There are workarounds available to mitigate the effects of the vulnerability.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20051201-http.

Affected Products

This section provides details on affected products.

Vulnerable Products

This security advisory applies to all Cisco products that run Cisco IOS Software versions 11.0 through 12.4 with the HTTP server enabled. A system which contains the IOS HTTP server or HTTP secure server, but does not have it enabled, is not affected.

To determine if the HTTP server is running on your device, issue the show ip http server status and show ip http server secure status commands at the prompt and look for output similar to:

Router>show ip http server status
HTTP server status: Enabled

If the device is not running the HTTP server, you should see output similar to:

Router>show ip http server status
HTTP server status: Disabled

Any version of Cisco IOS prior to the versions which will be listed in the Fixed Software section below may be vulnerable.

Products Confirmed Not Vulnerable

Cisco IOS XR is not affected.

To determine the software running on a Cisco product, log in to the device and issue the show version command to display the system banner. Cisco IOS Software will identify itself as "Internetwork Operating System Software" or simply "IOS". On the next line of output, the image name will be displayed between parentheses, followed by "Version" and the IOS release name. Other Cisco devices will not have the show version command or will give different output.

The following example identifies a Cisco product running IOS release 12.3(6) with an installed image name of C3640-I-M:

Cisco Internetwork Operating System Software
IOS (tm) 3600 Software (C3640-I-M), Version 12.3(6), RELEASE SOFTWARE (fc3)

The next example shows a product running IOS release 12.3(11)T3 with an image name of C3845-ADVIPSERVICESK9-M:

Cisco IOS Software, 3800 Software (C3845-ADVIPSERVICESK9-M), Version 12.3(11)T3, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2005 by Cisco Systems, Inc.

Additional information about Cisco IOS release naming can be found at http://www.cisco.com/warp/public/620/1.html.

No other Cisco products are currently known to be affected by these vulnerabilities.

Details

The Cisco IOS Web browser interface (which enables the device to perform as an HTTP server) allows configuration and monitoring of a router or access server using any web browser. This feature was introduced in IOS 11.0.

A vulnerability exists in the IOS HTTP server in which HTML code inserted into dynamically generated output, such as the output from a show buffers command, will be passed to the browser requesting the page. This HTML code could be interpreted by the browser and potentially execute malicious commands against the device or other possible cross-site scripting attacks.

In order to be vulnerable to the cross-site scripting attack, a user must browse and view the content during the same period of time the injected code exists in memory. On the other hand, if a user does not browse contaminated dynamic content on the device, then exploitation is not possible.

A proof of concept exploit exists for this vulnerability, in which the exploit attempts to reset the enable password on the device. For the attack to work against the device itself, the user browsing tainted dynamic content on the router will only be able to execute commands at or below the privilege level for which they are authenticated and authorized for on the device.

This vulnerability is documented in Cisco Bug ID CSCsc64976 ( registered customers only) .

Vulnerability Scoring Details

Impact

Successful exploitation of the vulnerability may result in an attacker executing commands on the device, including the possibility of gaining full administrative privileges on the device which is dependent on the privilege level of the authenticated user.

Software Versions and Fixes

When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.

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 Technical Assistance Center (TAC) or your contracted maintenance provider for assistance.

Each row of the Cisco IOS software table (below) names a Cisco IOS release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. Cisco recommends upgrading to the latest available release where possible.

Major Release

     Availability of Repaired Releases

Affected 12.0-Based Releases

First Fixed Release

12.0

Vulnerable; first fixed in 12.2

12.0DA

Vulnerable; first fixed in 12.2DA

12.0DB

Vulnerable; first fixed in 12.2

12.0DC

Vulnerable; first fixed in 12.2

12.0S

12.0(33)S

12.0(32)S6

12.0SC

Vulnerable; first fixed in 12.0S

12.0SL

Vulnerable; first fixed in 12.0S

12.0SP

Vulnerable; first fixed in 12.2

12.0ST

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.0SX

Vulnerable; first fixed in 12.0S

12.0SY

12.0(32)SY9a

12.0(32)SY3

12.0SZ

12.0(30)SZ4

12.0T

Vulnerable; first fixed in 12.2

12.0W

Vulnerable; first fixed in 12.2

12.0WC

12.0(5)WC14

12.0WT

Vulnerable; first fixed in 12.2

12.0XA

Vulnerable; first fixed in 12.2

12.0XB

Vulnerable; first fixed in 12.2

12.0XC

Vulnerable; first fixed in 12.2

12.0XD

Vulnerable; first fixed in 12.2

12.0XE

Vulnerable; first fixed in 12.2

12.0XF

Not Vulnerable

12.0XG

Vulnerable; first fixed in 12.2

12.0XH

Vulnerable; first fixed in 12.2

12.0XI

Vulnerable; first fixed in 12.2

12.0XJ

Vulnerable; first fixed in 12.2

12.0XK

Vulnerable; first fixed in 12.2

12.0XL

Vulnerable; first fixed in 12.2

12.0XM

Vulnerable; first fixed in 12.2

12.0XN

Vulnerable; first fixed in 12.2

12.0XQ

Vulnerable; first fixed in 12.2

12.0XR

Vulnerable; first fixed in 12.2

12.0XS

Not Vulnerable

12.0XT

Vulnerable; first fixed in 12.2

12.0XV

Vulnerable; first fixed in 12.2

Affected 12.1-Based Releases

First Fixed Release

12.1

Vulnerable; first fixed in 12.2

12.1AA

Vulnerable; first fixed in 12.2

12.1AX

Vulnerable; first fixed in 12.2SE

12.1AY

Vulnerable; first fixed in 12.1EA

12.1AZ

Vulnerable; first fixed in 12.1EA

12.1CX

Vulnerable; first fixed in 12.2

12.1DA

Vulnerable; first fixed in 12.2DA

12.1DB

Vulnerable; first fixed in 12.2

12.1DC

Vulnerable; first fixed in 12.2

12.1E

12.1(26)E8

12.1(27b)E1

12.1EA

12.1(22)EA7

12.1EB

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.1EC

Vulnerable; first fixed in 12.3BC

12.1EO

12.1(19)EO6

12.1EU

Vulnerable; first fixed in 12.2EWA

12.1EV

Vulnerable; first fixed in 12.2

12.1EW

Vulnerable; first fixed in 12.2

12.1EX

Vulnerable; first fixed in 12.2

12.1EY

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.1EZ

Vulnerable; first fixed in 12.2

12.1GA

Vulnerable; first fixed in 12.2

12.1GB

Vulnerable; first fixed in 12.2

12.1T

Vulnerable; first fixed in 12.2

12.1XA

Vulnerable; first fixed in 12.2

12.1XB

Vulnerable; first fixed in 12.2

12.1XC

Vulnerable; first fixed in 12.2

12.1XD

Vulnerable; first fixed in 12.2

12.1XE

Vulnerable; first fixed in 12.2

12.1XF

Vulnerable; first fixed in 12.2

12.1XG

Vulnerable; first fixed in 12.2

12.1XH

Vulnerable; first fixed in 12.2

12.1XI

Vulnerable; first fixed in 12.2

12.1XJ

Vulnerable; first fixed in 12.2

12.1XL

Vulnerable; first fixed in 12.2

12.1XM

Vulnerable; first fixed in 12.2

12.1XP

Vulnerable; first fixed in 12.2

12.1XQ

Vulnerable; first fixed in 12.2

12.1XR

Vulnerable; first fixed in 12.2

12.1XS

Vulnerable; first fixed in 12.2

12.1XT

Vulnerable; first fixed in 12.2

12.1XU

Vulnerable; first fixed in 12.2

12.1XV

Vulnerable; first fixed in 12.2

12.1XW

Vulnerable; first fixed in 12.2

12.1XX

Vulnerable; first fixed in 12.2

12.1XY

Vulnerable; first fixed in 12.2

12.1XZ

Vulnerable; first fixed in 12.2

12.1YA

Vulnerable; first fixed in 12.2

12.1YB

Vulnerable; first fixed in 12.2

12.1YC

Vulnerable; first fixed in 12.2

12.1YD

Vulnerable; first fixed in 12.2

12.1YE

Vulnerable; first fixed in 12.2

12.1YF

Vulnerable; first fixed in 12.2

12.1YH

Vulnerable; first fixed in 12.2

12.1YI

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.1YJ

Vulnerable; first fixed in 12.1EA

Affected 12.2-Based Releases

First Fixed Release

12.2

12.2(27c)

12.2(29b)

12.2(28d)

12.2(26c)

12.2(34)

12.2B

Vulnerable; first fixed in 12.3

12.2BC

Vulnerable; first fixed in 12.3

12.2BW

Vulnerable; first fixed in 12.3

12.2BX

Vulnerable; first fixed in 12.3

12.2BY

Vulnerable; first fixed in 12.3

12.2BZ

Vulnerable; first fixed in 12.3

12.2CX

Vulnerable; first fixed in 12.3

12.2CY

Vulnerable; first fixed in 12.3

12.2CZ

Vulnerable; first fixed in 12.2S

12.2DA

12.2(10)DA7

12.2(12)DA11

12.2DD

Vulnerable; first fixed in 12.3

12.2DX

Vulnerable; first fixed in 12.3

12.2EW

Vulnerable; first fixed in 12.2EWA

12.2EWA

12.2(25)EWA8

12.2(25)EWA6

12.2(25)EWA11

12.2EX

12.2(35)EX

12.2EY

12.2(37)EY

12.2EZ

Vulnerable; migrate to any release in 12.2SEE

12.2FX

Vulnerable; migrate to any release in 12.2SEE

12.2FY

Vulnerable; migrate to any release in 12.2SEG

12.2FZ

Not Vulnerable

12.2IRA

Not Vulnerable

12.2IRB

Not Vulnerable

12.2IRC

Not Vulnerable

12.2IRD

Not Vulnerable

12.2IXA

Vulnerable; first fixed in 12.2IXD

12.2IXB

Vulnerable; first fixed in 12.2IXD

12.2IXC

Vulnerable; first fixed in 12.2IXD

12.2IXD

12.2(18)IXD1

12.2IXE

Not Vulnerable

12.2IXF

Not Vulnerable

12.2IXG

Not Vulnerable

12.2IXH

Not Vulnerable

12.2JA

Vulnerable; first fixed in 12.3JA

12.2JK

Vulnerable; first fixed in 12.3JK

12.2MB

Vulnerable; first fixed in 12.3

12.2MC

12.2(15)MC2h

12.2S

12.2(14)S18

12.2(18)S13

12.2(25)S11

12.2(20)S13

12.2SB

12.2(31)SB3x

12.2(28)SB2

12.2(31)SB2

12.2SBC

Vulnerable; first fixed in 12.2SB

12.2SCA

Not Vulnerable

12.2SCB

Not Vulnerable

12.2SCC

Not Vulnerable

12.2SE

12.2(35)SE

12.2SEA

Vulnerable; migrate to any release in 12.2SEE

12.2SEB

Vulnerable; migrate to any release in 12.2SEE

12.2SEC

Vulnerable; migrate to any release in 12.2SEE

12.2SED

Vulnerable; migrate to any release in 12.2SEE

12.2SEE

Not Vulnerable

12.2SEF

Not Vulnerable

12.2SEG

Not Vulnerable

12.2SG

12.2(25)SG2

12.2(31)SG1

12.2(31)SG

12.2SGA

12.2(31)SGA6

12.2(31)SGA

12.2(31)SGA3

12.2SL

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2SM

12.2(29)SM2

12.2SO

12.2(18)SO7

12.2SQ

Not Vulnerable

12.2SRA

Not Vulnerable

12.2SRB

Not Vulnerable

12.2SRC

Not Vulnerable

12.2SRD

Not Vulnerable

12.2SRE

Not Vulnerable

12.2STE

Not Vulnerable

12.2SU

Vulnerable; first fixed in 12.4

12.2SV

12.2(29)SV3

12.2(29b)SV

12.2(27)SV5

12.2(28)SV2

12.2(29a)SV1

12.2SVA

Not Vulnerable

12.2SVC

Not Vulnerable

12.2SVD

Not Vulnerable

12.2SVE

Not Vulnerable

12.2SW

12.2(25)SW11

12.2SX

Vulnerable; first fixed in 12.2SXF

12.2SXA

Vulnerable; first fixed in 12.2SXF

12.2SXB

Vulnerable; first fixed in 12.2SXD

12.2SXD

12.2(18)SXD7b

12.2SXE

12.2(18)SXE6b

12.2SXF

12.2(18)SXF15a

12.2(18)SXF5

12.2(18)SXF17a

12.2SXH

Not Vulnerable

12.2SXI

Not Vulnerable

12.2SY

Vulnerable; first fixed in 12.2S

12.2SZ

Vulnerable; first fixed in 12.2S

12.2T

Vulnerable; first fixed in 12.3

12.2TPC

12.2(8)TPC10b

12.2XA

Vulnerable; first fixed in 12.3

12.2XB

Vulnerable; first fixed in 12.3

12.2XC

Vulnerable; first fixed in 12.3

12.2XD

Vulnerable; first fixed in 12.3

12.2XE

Vulnerable; first fixed in 12.3

12.2XF

Vulnerable; first fixed in 12.3

12.2XG

Vulnerable; first fixed in 12.3

12.2XH

Vulnerable; first fixed in 12.3

12.2XI

Vulnerable; first fixed in 12.3

12.2XJ

Vulnerable; first fixed in 12.3

12.2XK

Vulnerable; first fixed in 12.3

12.2XL

Vulnerable; first fixed in 12.3

12.2XM

Vulnerable; first fixed in 12.3

12.2XN

Not Vulnerable

12.2XNA

Not Vulnerable

12.2XNB

Not Vulnerable

12.2XNC

Not Vulnerable

12.2XND

Not Vulnerable

12.2XNE

Not Vulnerable

12.2XO

Not Vulnerable

12.2XQ

Vulnerable; first fixed in 12.3

12.2XR

Vulnerable; first fixed in 12.3JA

12.2XS

Vulnerable; first fixed in 12.3

12.2XT

Vulnerable; first fixed in 12.3

12.2XU

Vulnerable; first fixed in 12.3

12.2XV

Vulnerable; first fixed in 12.3

12.2XW

Vulnerable; first fixed in 12.3

12.2YA

Vulnerable; first fixed in 12.3

12.2YB

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YC

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YD

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YE

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YF

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YG

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YH

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YJ

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YK

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YL

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YM

Vulnerable; first fixed in 12.4

12.2YN

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YO

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YP

Vulnerable; first fixed in 12.3

12.2YQ

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YR

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YS

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YT

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YU

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YV

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YW

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YX

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YY

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2YZ

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZA

Vulnerable; first fixed in 12.2SXD

12.2ZB

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZC

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZD

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZE

Vulnerable; first fixed in 12.3

12.2ZF

Vulnerable; first fixed in 12.4

12.2ZG

Vulnerable; first fixed in 12.4

12.2ZH

12.2(13)ZH9

12.2ZJ

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZL

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZP

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.2ZU

12.2(18)ZU2

12.2ZX

Vulnerable; first fixed in 12.2SB

12.2ZY

Not Vulnerable

12.2ZYA

12.2(18)ZYA

Affected 12.3-Based Releases

First Fixed Release

12.3

12.3(17c)

12.3(18)

12.3B

Vulnerable; first fixed in 12.4

12.3BC

12.3(21)BC

12.3(17b)BC5

12.3BW

Vulnerable; first fixed in 12.4

12.3EU

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.3JA

12.3(8)JA

12.3(7)JA3

12.3(2)JA6

12.3(4)JA2

12.3JEA

12.3(8)JEA

12.3JEB

Not Vulnerable

12.3JEC

Not Vulnerable

12.3JED

Not Vulnerable

12.3JK

12.3(8)JK

12.3(2)JK3

12.3JL

Not Vulnerable

12.3JX

Not Vulnerable

12.3T

Vulnerable; first fixed in 12.4

12.3TPC

12.3(4)TPC11b

12.3VA

Vulnerable; first fixed in 12.4T

12.3XA

12.3(2)XA6

12.3XB

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.3XC

12.3(2)XC5

12.3XD

Vulnerable; first fixed in 12.4

12.3XE

12.3(2)XE5

12.3XF

Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory

12.3XG

Vulnerable; first fixed in 12.4

12.3XI

12.3(7)XI9

12.3XJ

Vulnerable; first fixed in 12.3YX

12.3XK

Vulnerable; first fixed in 12.4

12.3XL

Vulnerable; first fixed in 12.4T

12.3XQ

Vulnerable; first fixed in 12.4

12.3XR

12.3(7)XR7

12.3XS

Vulnerable; first fixed in 12.4

12.3XU

Vulnerable; first fixed in 12.4T

12.3XW

Vulnerable; first fixed in 12.3YX

12.3XX

12.3(8)XX2d

12.3XY

Vulnerable; first fixed in 12.4

12.3XZ

Vulnerable; first fixed in 12.4

12.3YA

Vulnerable; first fixed in 12.4

12.3YD

Vulnerable; first fixed in 12.4T

12.3YF

Vulnerable; first fixed in 12.3YX

12.3YG

12.3(8)YG6

12.3YH

Vulnerable; first fixed in 12.4T

12.3YI

Vulnerable; first fixed in 12.4T

12.3YJ

Vulnerable; first fixed in 12.4T

12.3YK

12.3(11)YK3

12.3YM

12.3(14)YM10

12.3YQ

Vulnerable; first fixed in 12.4T

12.3YS

12.3(11)YS2

12.3YT

Vulnerable; first fixed in 12.4T

12.3YU

Vulnerable; first fixed in 12.4XB

12.3YX

12.3(14)YX8

12.3YZ

12.3(11)YZ2

12.3ZA

Vulnerable; first fixed in 12.4T

Affected 12.4-Based Releases

First Fixed Release

12.4

12.4(7)

12.4(5c)

12.4(3g)

12.4GC

Not Vulnerable

12.4JA

12.4(3g)JA

12.4JDA

Not Vulnerable

12.4JDC

Not Vulnerable

12.4JDD

Not Vulnerable

12.4JK

Not Vulnerable

12.4JL

Not Vulnerable

12.4JMA

Not Vulnerable

12.4JMB

Not Vulnerable

12.4JX

Not Vulnerable

12.4MD

12.4(11)MD

12.4MDA

Not Vulnerable

12.4MR

12.4(6)MR

12.4SW

Not Vulnerable

12.4T

12.4(2)T6

12.4(6)T

12.4(4)T5

12.4XA

Vulnerable; first fixed in 12.4T

12.4XB

12.4(2)XB6

12.4XC

12.4(4)XC6

12.4XD

12.4(4)XD4

12.4XE

Not Vulnerable

12.4XF

Not Vulnerable

12.4XG

Not Vulnerable

12.4XJ

Not Vulnerable

12.4XK

Not Vulnerable

12.4XL

Not Vulnerable

12.4XM

Not Vulnerable

12.4XN

Not Vulnerable

12.4XP

Not Vulnerable

12.4XQ

Not Vulnerable

12.4XR

Not Vulnerable

12.4XT

Not Vulnerable

12.4XV

Not Vulnerable

12.4XW

Not Vulnerable

12.4XY

Not Vulnerable

12.4XZ

Not Vulnerable

12.4YA

Not Vulnerable

12.4YB

Not Vulnerable

12.4YD

Not Vulnerable

12.4YE

Not Vulnerable

12.4YG

Not Vulnerable

Affected 15.0-Based Releases

First Fixed Release

There are no affected 15.0 based releases

Affected 15.1-Based Releases

First Fixed Release

There are no affected 15.1 based releases


Workarounds

If the HTTP server is not used for any legitimate purposes on the device, it is a best practice to disable it by issuing the following commands in configure mode:

no ip http server
no ip http secure-server

Disable the HTTP WEB_EXEC Service

A feature was introduced in 12.3(14)T and later in which selective HTTP and HTTPS services could be enabled or disabled. The WEB_EXEC service provides a facility to configure the box and retrieve the current state of the box from remote clients.

It is possible to disable the WEB_EXEC service while still leaving other HTTP services active. If an installation does not require the use of the WEB_EXEC service, then it may be disabled using the following procedure:

  1. Verify the list of all session modules.
    Router#show ip http server session-module 
    HTTP server application session modules: 
     Session module Name  Handle Status   Secure-status  Description 
    HTTP_IFS              1      Active   Active         HTTP based IOS File Server 
    HOME_PAGE             2      Active   Active         IOS Homepage Server 
    QDM                   3      Active   Active         QOS Device Manager Server 
    QDM_SA                4      Active   Active         QOS Device Manager Signed Applet Server 
    WEB_EXEC              5      Active   Active         HTTP based IOS EXEC Server 
    IXI                   6      Active   Active         IOS XML Infra Application Server 
    IDCONF                7      Active   Active         IDCONF HTTP(S) Server 
    XSM                   8      Active   Active         XML Session Manager 
    VDM                   9      Active   Active         VPN Device Manager Server 
    XML_Api               10     Active   Active         XML Api 
    ITS                   11     Active   Active         IOS Telephony Service 
    ITS_LOCDIR            12     Active   Active         ITS Local Directory Search 
    CME_SERVICE_URL       13     Active   Active         CME Service URL 
    CME_AUTH_SRV_LOGIN    14     Active   Active         CME Authentication Server 
    IPS_SDEE              15     Active   Active         IOS IPS SDEE Server 
    tti-petitioner        16     Active   Active         TTI Petitioner
  2. Create a list of session modules that are required, in this example it would be everything other than WEB_EXEC.
    Router#configuration terminal
    Router(config)#ip http session-module-list exclude_webexec 
                 HTTP_IFS,HOME_PAGE,QDM,QDM_SA,IXI,IDCONF,XSM,VDM,XML_Api,
                 ITS,ITS_LOCDIR,CME_SERVICE_URL,CME_AUTH_SRV_LOGIN,IPS_SDEE,tti-petitioner
    
  3. Selectively enable HTTP/HTTPS applications that will service incoming HTTP requests from remote clients.
    Router(config)#ip http active-session-modules exclude_webexec 
    Router(config)#ip http secure-active-session-modules exclude_webexec 
    Router(config)#exit 
    
  4. Verify the list of all session modules, and ensure WEB_EXEC is not active.
    Router#show ip http server session-module 
    HTTP server application session modules: 
     Session module Name  Handle Status   Secure-status  Description 
    HTTP_IFS              1      Active   Active         HTTP based IOS File Server 
    HOME_PAGE             2      Active   Active         IOS Homepage Server 
    QDM                   3      Active   Active         QOS Device Manager Server 
    QDM_SA                4      Active   Active         QOS Device Manager Signed Applet Server 
    WEB_EXEC              5      Inactive Inactive       HTTP based IOS EXEC Server 
    IXI                   6      Active   Active         IOS XML Infra Application Server 
    IDCONF                7      Active   Active         IDCONF HTTP(S) Server 
    XSM                   8      Active   Active         XML Session Manager 
    VDM                   9      Active   Active         VPN Device Manager Server 
    XML_Api               10     Active   Active         XML Api 
    ITS                   11     Active   Active         IOS Telephony Service 
    ITS_LOCDIR            12     Active   Active         ITS Local Directory Search 
    CME_SERVICE_URL       13     Active   Active         CME Service URL 
    CME_AUTH_SRV_LOGIN    14     Active   Active         CME Authentication Server 
    IPS_SDEE              15     Active   Active         IOS IPS SDEE Server 
    tti-petitioner        16     Active   Active         TTI Petitioner 

For further information on selective enabling of applications using an HTTP or secure HTTP server, consult the Cisco IOS network management configuration guide, release 12.4T at: http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_http_app_enable.html

Avoid the use of Web-based SHOW commands

Successful exploitation of this vulnerability requires an unsuspecting user to request dynamic content from the device via the "show" commands which are available. Avoiding the use of those commands via the web interface until an upgrade to fixed software is possible may be perfectly legitimate for some installations.

Obtaining Fixed Software

Cisco will make free software available to address this vulnerability for affected customers. This advisory will be updated as fixed software becomes available. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets they have purchased. By installing, downloading, accessing or otherwise using such software upgrades, customers agree to be bound by the terms of Cisco's software license terms found at http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

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

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. 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 Using Third-Party Support Organizations

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 guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer situations such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.

Customers Without Service Contracts

Customers who purchase direct 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 get their upgrades by contacting the Cisco Technical Assistance Center (TAC). 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

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.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including special localized telephone numbers and instructions and e-mail addresses for use in various languages.

Exploitation and Public Announcements

This vulnerability was disclosed in a public posting to the Bugtraq mailing list.

We would like to thank iDefense for finding and initially reporting this vulnerability to us.

We would also like to thank Mr. Adrian Pastor from ProCheckup Ltd for sharing information with us about another possible vector into this vulnerability. His research paper is available at http://www.procheckup.com/vulnerability_manager/vulnerabilities/paper-04 leavingcisco.com.

The Cisco PSIRT is not aware of any malicious use of the vulnerability described in this advisory.

Status of This Notice: Final

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.


Distribution

This advisory is posted on Cisco's worldwide website at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20051201-http.

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
  • first-teams@first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk
  • comp.dcom.sys.cisco@newsgate.cisco.com

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


Revision History

Revision 2.0

29-March-2010

Updated the Software Versions and Fixes section.

Revision 1.3

22-October-2009

Updated the Exploitation and Public Announcements to include additional researcher information.

Revision 1.2

19-June-2009

Revised the Disable the HTTP WEB_EXEC Service section.

Revision 1.1

14-January-2006

Added additional advisory credits.

Revision 1.0

1-December-2005

Initial public release.

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/web/about/security/psirt/security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt/.


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