__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Cisco IOS Secure Copy Authorization Bypass Vulnerability [Cisco Security Advisory Document ID: 97261] August 15, 2007 19:00 GMT Number R-327 ______________________________________________________________________________ PROBLEM: The server side of the Secure Copy (SCP) implementation in Cisco Internetwork Operating System (IOS) contains a vulnerability that allows any valid user, regardless of privilege level, to transfer files to and from an IOS device that is configured to be a Secure Copy server. PLATFORM: Cisco devices running certain 12.2-based IOS releases and configured to offer Secure Copy server functionality are affected by this issue. DAMAGE: Could allow valid users to retrieve or write to any file on the device's filesystem, including the device's saved configuration. SOLUTION: Upgrade to the appropriate version. ______________________________________________________________________________ VULNERABILITY The risk is LOW. Could allow valid users to retrieve or write ASSESSMENT: to any file on the device's filesystem, including the device's saved configuration. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/r-327.shtml ORIGINAL BULLETIN: http://www.cisco.com/en/US/products/products_security_ advisory09186a0080899636.shtml ______________________________________________________________________________ [***** Start Cisco Security Advisory Document ID: 97261 *****] Cisco Security Advisory: Cisco IOS Secure Copy Authorization Bypass Vulnerability Document ID: 97261 Advisory ID: cisco-sa-20070808-scp http://www.cisco.com/warp/public/707/cisco-sa-20070808-scp.shtml Revision 1.0 For Public Release 2007 August 08 1600 UTC (GMT) -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Contents Summary Affected Products Details Vulnerability Scoring Details Impact Software Versions and Fixes Workarounds Obtaining Fixed Software Exploitation and Public Announcements Status of this Notice: FINAL Distribution Revision History Cisco Security Procedures -------------------------------------------------------------------------------- Summary The server side of the Secure Copy (SCP) implementation in Cisco Internetwork Operating System (IOS) contains a vulnerability that allows any valid user, regardless of privilege level, to transfer files to and from an IOS device that is configured to be a Secure Copy server. This vulnerability could allow valid users to retrieve or write to any file on the device's filesystem, including the device's saved configuration. This configuration file may include passwords or other sensitive information. The IOS Secure Copy Server is an optional service that is disabled by default. Devices that are not specifically configured to enable the IOS Secure Copy Server service are not affected by this vulnerability. This vulnerability does not apply to the IOS Secure Copy Client feature. This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20070808-scp.shtml. Note: The August 08, 2007 publication includes four Security Advisories and one Security Response. The advisories all affect IOS, one additionally affects Cisco Unified Communications Manager as well. Each advisory lists the releases that correct the vulnerability described in the advisory, and the advisories also detail the releases that correct the vulnerabilities in all four advisories. Individual publication links are listed below: Cisco IOS Information Leakage Using IPv6 Routing Header http://www.cisco.com/warp/public/707/cisco-sa-20070808-IOS-IPv6-leak.shtml Cisco IOS Next Hop Resolution Protocol Vulnerability http://www.cisco.com/warp/public/707/cisco-sa-20070808-nhrp.shtml Cisco IOS Secure Copy Authorization Bypass Vulnerability http://www.cisco.com/warp/public/707/cisco-sa-20070808-scp.shtml Voice Vulnerabilities in Cisco IOS and Cisco Unified Communications Manager http://www.cisco.com/warp/public/707/cisco-sa-20070808-IOS-voice.shtml Cisco Unified MeetingPlace XSS Vulnerability http://www.cisco.com/warp/public/707/cisco-sr-20070808-mp.shtml Affected Products Vulnerable Products Cisco devices running certain 12.2-based IOS releases and configured to offer Secure Copy server functionality are affected by this issue. A device running a vulnerable Cisco IOS 12.2-based is affected if the following command is present in the device configuration: ip scp server enable The IOS Secure Copy server is disabled by default. The Secure Copy server functionality is only available on encryption-capable images. Devices that do not run an encryption-capable images, which contain either k8 or k9 in the image name, are not vulnerable. If a device is running an encryption-capable image, the existence of the ip scp server enable command in the configuration will determine whether the device is affected. Please consult the table of fixed software in the Software Version and Fixes section for the specific 12.2-based IOS releases that are 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". The image name will be displayed between parentheses on the next line of output followed by "Version" and 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 12.2(18)SXF10: Cisco Internetwork Operating System Software IOS (tm) s72033_rp Software (s72033_rp-IPSERVICESK9-M), Version 12.2(18)SXF10, RELEASE SOFTWARE (fc1) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2007 by cisco Systems, Inc. Compiled Fri 13-Jul-07 08:32 by kellythwAdditional information about Cisco IOS release naming is available at http://www.cisco.com/warp/public/620/1.html. Products Confirmed Not Vulnerable Cisco devices that do not run IOS are not affected. Cisco IOS devices that do not have the Secure Copy server feature enabled are not affected. The following IOS release trains are not affected: 12.0-based releases 12.1-based releases 12.3-based releases 12.4-based releases Cisco IOS XR is not affected. No other Cisco devices are known to be affected. Details Secure Copy (SCP) is a protocol similar to the Remote Copy (RCP) protocol, which allows for the transfer of files between systems. The main difference between SCP and RCP is that in SCP, all aspects of the file transfer session, including authentication, occur in encrypted form, which makes SCP a more secure alternative than RCP. SCP relies on the Secure Shell (SSH) protocol, which uses TCP port 22 by default. The server side of the Secure Copy implementation in Cisco IOS contains a vulnerability that allows any valid user, regardless of privilege level, to transfer files to and from an IOS device that is configured to be a Secure Copy server. This vulnerability could allow valid users to retrieve or write to any file on the device's filesystem, including the device's saved configuration. This configuration file may include passwords or other sensitive information. This vulnerability does not allow for authentication bypass; login credentials are verified and access is only granted if a valid username and password is provided. This vulnerability may cause authorization to be bypassed. A device with the Secure Copy server enabled is vulnerable regardless of whether Authentication, Authorization, and Accounting (AAA) is enabled. If access control is enabled on the Virtual Terminal (vty) via the login command, which allows logins via Virtual Terminals, then the device is affected. This vulnerability is documented in Cisco Bug ID CSCsc19259 ( registered customers only) . Vulnerability Scoring Details Cisco is providing scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 1.0. Cisco will provide a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks. Cisco PSIRT will set the bias in all cases to normal. Customers are encouraged to apply the bias parameter when determining the environmental impact of a particular vulnerability. CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response. Cisco has provided an FAQ to answer additional questions regarding CVSS at http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html. Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at http://intellishield.cisco.com/security/alertmanager/cvss. CSCsc19259 Calculate the environmental score of CSCsc19259 CVSS Base Score - 6.0 Access Vector Access Complexity Authentication Confidentiality Impact Integrity Impact Availability Impact Impact Bias Remote Low Required Complete Complete Complete Normal CVSS Temporal Score - 5.0 Exploitability Remediation Level Report Confidence Functional Official-Fix Confirmed Impact Successful exploitation of the vulnerability described in this advisory may allow valid but unauthorized users to retrieve or write to any file on the device's filesystem, including the device's saved configuration. This configuration file may include passwords or other sensitive information. 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. The "Recommended Release" column indicates the releases which have fixes for all the published vulnerabilities at the time of this Advisory. A device running a release in the given train that is earlier than the release in a specific column (less than the First Fixed Release) is known to be vulnerable. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table. For further information about how Cisco IOS is built, numbered and maintained, please see the following URL: http://www.cisco.com/warp/public/620/1.html Major Release Availability of Repaired Releases Affected 12.0-Based Release First Fixed Release Recommended Release There are no affected 12.0 based releases Affected 12.1-Based Release First Fixed Release Recommended Release There are no affected 12.1 based releases Affected 12.2-Based Release First Fixed Release Recommended Release 12.2 Not Vulnerable 12.2B Not Vulnerable 12.2BC Not Vulnerable 12.2BW Not Vulnerable 12.2BY Not Vulnerable 12.2BZ Not Vulnerable 12.2CX Not Vulnerable 12.2CY Not Vulnerable 12.2CZ Not Vulnerable 12.2DA Not Vulnerable 12.2DD Not Vulnerable 12.2DX Not Vulnerable 12.2EU Not Vulnerable 12.2EW Not Vulnerable 12.2EWA Not Vulnerable 12.2EX Not Vulnerable 12.2EY Not Vulnerable 12.2EZ Not Vulnerable 12.2FX Not Vulnerable 12.2FY Not Vulnerable 12.2FZ Not Vulnerable 12.2IXA Vulnerable; first fixed in 12.2(18)IXD1 12.2(18)IXD1 12.2IXB Vulnerable; first fixed in 12.2(18)IXD1 12.2(18)IXD1 12.2IXC Vulnerable; first fixed in 12.2(18)IXD1 12.2(18)IXD1 12.2IXD 12.2(18)IXD1 12.2(18)IXD1 12.2JA Not Vulnerable 12.2JK Not Vulnerable 12.2MB Not Vulnerable 12.2MC Not Vulnerable 12.2S Not Vulnerable 12.2SB Not Vulnerable 12.2SBC Not Vulnerable 12.2SE Not Vulnerable 12.2SEA Not Vulnerable 12.2SEB Not Vulnerable 12.2SEC Not Vulnerable 12.2SED Not Vulnerable 12.2SEE Not Vulnerable 12.2SEF Not Vulnerable 12.2SEG Not Vulnerable 12.2SG Not Vulnerable 12.2SGA Not Vulnerable 12.2SL Not Vulnerable 12.2SM Not Vulnerable 12.2SO Not Vulnerable 12.2SRA Not Vulnerable 12.2SRB Not Vulnerable 12.2SU Not Vulnerable 12.2SV Not Vulnerable 12.2SVA Not Vulnerable 12.2SVC Not Vulnerable 12.2SW Not Vulnerable 12.2SX Not Vulnerable 12.2SXA Not Vulnerable 12.2SXB Not Vulnerable 12.2SXD Vulnerable; contact TAC 12.2SXE Vulnerable; first fixed in 12.2(18)SXF9 12.2(18)SXF10 12.2SXF 12.2(18)SXF9 12.2(18)SXF10 12.2SXH Not Vulnerable 12.2SY Not Vulnerable 12.2SZ Not Vulnerable 12.2T Not Vulnerable 12.2TPC Not Vulnerable 12.2UZ Not Vulnerable 12.2VZ Not Vulnerable 12.2XA Not Vulnerable 12.2XB Not Vulnerable 12.2XC Not Vulnerable 12.2XD Not Vulnerable 12.2XE Not Vulnerable 12.2XF Not Vulnerable 12.2XG Not Vulnerable 12.2XH Not Vulnerable 12.2XI Not Vulnerable 12.2XJ Not Vulnerable 12.2XK Not Vulnerable 12.2XL Not Vulnerable 12.2XM Not Vulnerable 12.2XN Not Vulnerable 12.2XQ Not Vulnerable 12.2XR Not Vulnerable 12.2XS Not Vulnerable 12.2XT Not Vulnerable 12.2XU Not Vulnerable 12.2XV Not Vulnerable 12.2XW Not Vulnerable 12.2YA Not Vulnerable 12.2YB Not Vulnerable 12.2YC Not Vulnerable 12.2YD Not Vulnerable 12.2YE Not Vulnerable 12.2YF Not Vulnerable 12.2YG Not Vulnerable 12.2YH Not Vulnerable 12.2YJ Not Vulnerable 12.2YK Not Vulnerable 12.2YL Not Vulnerable 12.2YM Not Vulnerable 12.2YN Not Vulnerable 12.2YO Not Vulnerable 12.2YP Not Vulnerable 12.2YQ Not Vulnerable 12.2YR Not Vulnerable 12.2YS Not Vulnerable 12.2YT Not Vulnerable 12.2YU Not Vulnerable 12.2YV Not Vulnerable 12.2YW Not Vulnerable 12.2YX Not Vulnerable 12.2YY Not Vulnerable 12.2YZ Not Vulnerable 12.2ZA Not Vulnerable 12.2ZB Not Vulnerable 12.2ZC Not Vulnerable 12.2ZD Not Vulnerable 12.2ZE Not Vulnerable 12.2ZF Not Vulnerable 12.2ZG Not Vulnerable 12.2ZH Not Vulnerable 12.2ZJ Not Vulnerable 12.2ZL Not Vulnerable 12.2ZP Not Vulnerable 12.2ZR Not Vulnerable 12.2ZU Vulnerable; first fixed in 12.2(33)SXH available 31-Aug-07 12.2(33)SXH; available 31-Aug-07 12.2ZW Not Vulnerable 12.2ZY Not Vulnerable Affected 12.3-Based Release First Fixed Release Recommended Release There are no affected 12.3 based releases Affected 12.4-Based Release First Fixed Release Recommended Release There are no affected 12.4 based releases Workarounds If the IOS Secure Copy Server functionality is not needed then the vulnerability described in this document can be mitigated by disabling the Secure Copy server. The Secure Copy server can be disabled by executing the following command in global configuration mode: no ip scp server enable If the Secure Copy server cannot be disabled due to operational concerns, then no workarounds exist. The risk posed by this vulnerability can be mitigated by following the best practices detailed in "Improving Security on Cisco Routers" at http://www.cisco.com/warp/public/707/21.html. Please refer to the Obtaining Fixed Software section for appropriate solutions to resolve this vulnerability. Due to the nature of this vulnerability, networking best practices like access control lists (ACLs) and Control Plane Policing (CoPP) that restrict access to a device to certain IP addresses or subnetworks may not be effective. If access is already granted to a specific IP address or subnetwork, a user with low privileges will be able to establish a Secure Copy session with the device, which would allow the user to exploit this vulnerability. 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/public/sw-license-agreement.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/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. Exploitation and Public Announcements The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory. This vulnerability was reported to Cisco by Vijay Sarvepalli from University of North Carolina at Greensboro. 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://www.cisco.com/warp/public/707/cisco-sa-20070808-scp.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 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 1.0 2007-August-08 Initial public release [***** End Cisco Security Advisory Document ID: 97261 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Cisco for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) R-317: Vulnerability in OLE Automation R-318: Vulnerability in Microsoft Excel R-319: Cumulative Security Update for Internet Explorer R-320: Vulnerability in GDI R-321: Vulnerabilities in Windows Media Player R-322: Vulnerabilities in Windows Gadgets R-323: Vulnerability in Virtual PC and Virtual Server R-324: Vulnerability in Vector Markup Language R-325: Information Leakage Using IPv6 Routing Header R-326: tcpdump