-----BEGIN PGP SIGNED MESSAGE----- Security Advisory: IOS Reload after Scanning Vulnerability Revision 1.0 For Public Release 2001 May 24 08:00 (UTC -0800) ------------------------------------------------------------------------ Summary ======= Security Scanning software can cause a memory error in Cisco IOSŪ Software that will cause a reload to occur. This vulnerability affects only Cisco IOS software version 12.1(2)T and 12.1(3)T, and limited deployment releases based on those versions. Customers using the affected Cisco IOS software releases are urged to upgrade as soon as possible to later versions that are not vulnerable to this defect. Vulnerable products and releases are listed in detail below. The security scanner makes TCP connection attempts to various ports, looking for open ports to further investigate known vulnerabilities with those services associated with certain ports. However, a side effect of the tests exposes the defect described in this security advisory, and the router will reload unexpectedly as soon as it receives a request to review or write the configuration file. This defect is documented as Cisco Bug ID CSCds07326. The complete notice will be available at http://www.cisco.com/warp/public/707/ios-tcp-scanner-reload-pub.shtml. Affected Products ================= It is impossible to list all Cisco products in this notice; the lists below include only the most commonly used or most asked-about products. If you are unsure whether your device is running Cisco IOS software, log into the device and issue the command show version. Cisco IOS software will identify itself simply as "IOS" or "Internetwork Operating System Software". Other Cisco devices either will not have the show version command, or will give different output. Cisco devices that run Cisco IOS software include the following: * Cisco routers in the AGS/MGS/CGS/AGS+, IGS, RSM, 8xx, ubr9xx, 1xxx, 25xx, 26xx, 30xx, 36xx, 38xx, 40xx, 45xx, 47xx, AS52xx, * AS53xx, AS58xx, 64xx, 70xx, 72xx (including the ubr72xx), 75xx, and 12xxx series. * Most recent versions of the LS1010 ATM switch. * Some versions of the Catalyst 2900XL LAN switch. * The Cisco DistributedDirector. The affected software versions are relatively new, and are not necessarily available on every device listed above. If you are not running Cisco IOS software, you are not affected by this vulnerability. Cisco devices which do not run Cisco IOS software, and are not affected by this vulnerability, include the following: * 7xx dialup routers (750, 760, and 770 series) are not affected. * Catalyst 19xx, 28xx, 29xx, 3xxx, and 5xxx LAN switches are not affected, except for some versions of the Catalyst 2900XL. However, optional router modules running Cisco IOS software in switch backplanes, such as the RSM module for the Catalyst 5000 and 5500, are affected. * WAN switching products in the IGX and BPX lines are not affected. * The MGX (formerly known as the AXIS shelf) is not affected. * No host-based software is affected. * The Cisco PIX Firewall is not affected. * The Cisco LocalDirector is not affected. * The Cisco Cache Engine is not affected. * The Cisco CSS 11000 series switch is not affected Details ======= An attempt to make a TCP connection to ports 3100-3999, 5100-5999, 7100-7999, and 10100-10999 will cause the router to unexpectedly reload at the next show running-config, or write memory, or any command that causes the configuration file to be accessed. Cisco IOS software cannot be configured to support any services that might listen at those port addresses, and cannot be configured to accept connections on those ports, however, connection attempts to these ports in the affected version will cause memory corruption, later leading to an unexpected reload. Software packages are available from various commercial and free sites that perform automated remote tests for computer security vulnerabilities by scanning computers on a network for known security flaws. A common log message in environments that experienced security scan related crashes was the "attempt to connect to RSHELL" error message. Bug ID This problem was introduced in 12.1(1.3)T, and is identified by Cisco Bug ID CSCds07326. Impact ====== The described defect can be used to mount a denial of service (DoS) attack on any vulnerable Cisco product, which may result in violations of the availability aspects of a customer's security policy. This defect by itself does not cause the disclosure of confidential information nor allow unauthorized access. Software Versions and Fixes =========================== This defect was introduced in version 12.1(1.3)T, and is repaired in the following versions which are based on the 12.1(2)T and 12.1(3)T releases. The following table summarizes the Cisco IOS software releases that are known to be affected, and the earliest estimated dates of availability for the recommended fixed versions. Dates are always tentative and subject to change. 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 receive less testing. Interims should be selected only if there is no other suitable release that addresses the vulnerability, and interim images should be upgraded to the next available maintenance release as soon as possible. Interim releases are not available via manufacturing, and usually they are not available for customer download from CCO without prior arrangement with the Cisco TAC. In the table below, the logical superseding software is recommended when there is no rebuild or maintenance planned for a specific software release. Customers should verify that planned upgrades will meet their requirements. For further details, see the IOS Release Notes for each Cisco IOS Train. http://www.cisco.com/univercd/cc/td/doc/product/software/index.htm. 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 later in this notice. More information on Cisco IOS Software release names and abbreviations is available at http://www.cisco.com/warp/public/cc/pd/iosw/iore/prodlit/537_pp.htm. +===========================================================================+ | Major Description or | | Release Platform Availability of Repaired Releases* | +===========================================================================+ | Unaffected Earlier Releases Rebuild Interim** Maintenance | +===========================================================================+ |12.0 and | | | | |earlier, |Not |Not |Not | |all Numerous |vulnerable |vulnerable |vulnerable | |variants | | | | +===========================================================================+ | 12.1-based Releases | Rebuild | Interim** | Maintenance | +===========================================================================+ | General | | | | |12.1 Deployment (GD) |Not |Not |Not | | candidate: all |vulnerable |vulnerable |vulnerable | | platforms | | | | +----------+------------------+------------+-------------+------------------+ |12.1AA Dial Support |Not |Not |Not | | |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ |12.1CX Core/ISP support:|Not |Not |Not | | GSR, RSP, C7200 |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ |12.1DA xDSL Support: |Not |Not |Not | | 6100, 6200 |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Cisco 6400 | | | | |12.1DB Universal Access | | |12.1(4)DB | | Concentrator | | | | +----------+------------------+------------+-------------+------------------+ |12.1DC xDSL NRP support:| | |12.1(4)DC | | c6400r | | | | +----------+------------------+------------+-------------+------------------+ |12.1E Core/ISP Support:|Not |Not |Not | | GSR, RSP, c7200 |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1EC (ED): ubr7200, |Not |Not |Not | | UBR Headend |Vulnerable |Vulnerable |Vulnerable | | platforms | | | | +----------+------------------+------------+-------------+------------------+ |12.1EX Catalyst 6000 |Not |Not |Not | | |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ |12.1EY Catalyst 8510, |Not |Not |Not | | 8540, LS1010 |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | New technology | | | | |12.1T Early Deployment | |12.1(4.3)T |12.1(5)T | | (ED): all | | | | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XA (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XB (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XC (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XD (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XE (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XF (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XG (ED): limited | | |12.2T*** | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XH (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XI (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XJ (ED): limited | | |12.2T*** | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XK (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XL (ED): limited | | |12.2(1) | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XM (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XP (ED): limited | | |12.2T*** | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XQ (ED): limited | | |12.2T*** | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XR (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XS (ED): limited | | |12.1(5)XS | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XT (ED): limited | | |12.2T*** | | platforms | | | | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XU (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XV (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XW (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XX (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XY (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1XZ (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1YA (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1YB (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1YC (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +----------+------------------+------------+-------------+------------------+ | Early Deployment | | | | |12.1YD (ED): limited |Not |Not |Not | | platforms |Vulnerable |Vulnerable |Vulnerable | +===========================================================================+ | Notes | +===========================================================================+ |* All dates are estimated and subject to change. | | | |** Interim releases are subjected to less rigorous testing than | |regular maintenance releases, and may have serious bugs. | | | |*** This release does not have a rebuild solution. Customers should | |upgrade to 12.2T when it becomes available. This is not a misprint. | +===========================================================================+ Obtaining Fixed Software ======================== Cisco is offering free software upgrades to eliminate this vulnerability for all affected customers. 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 Web site 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 without contracts 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: tacat_private 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 "psirtat_private" or "security-alertat_private" for software upgrades. Workarounds =========== There are no direct configuration workarounds for this vulnerability. This vulnerability can be mitigated by applying access lists on external devices or firewalls to prevent connections to affected routers, and to eliminate router addresses in any planned security scanning exercises. Exploitation and Public Announcements ===================================== The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities described in this advisory. However, many reports of reloads related to this vulnerability have been reported by customers, due to customer use of security scanning software. 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. Distribution ============ This notice will be posted on Cisco's Worldwide Web site at http://www.cisco.com/warp/public/707/ios-tcp-scanner-reload-pub.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-announceat_private * bugtraqat_private * firewallsat_private * first-teamsat_private (includes CERT/CC) * ciscoat_private * cisco-nspat_private * comp.dcom.sys.cisco * 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 | 2001-May-24; 08:00 UTC -08:00 | Initial public release. | | 1.0 | | | +===========================================================================+ 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 Web site at http://www.cisco.com/warp/public/707/sec_incident_response.shtml. This includes instructions for press inquiries regarding Cisco security notices. ------------------------------------------------------------------------ This notice is Copyright 2001 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. ------------------------------------------------------------------------ -----BEGIN PGP SIGNATURE----- Version: PGP 7.0 iQEVAwUBOw01sGiN3BRdFxkbAQFWAwf/diDZ4ZDt9CIg8k0KdVaUGYzLhNCpXw37 0cefbFTVHb9eGpE5tuLf0Km/DNZcyRMJKzpzM15ueC98XflQBq9Hqi5SF4bjq2Df De65I0S4W0huyIqNqivu3M8O57FNs8HOXFf409CuFy8Q/8s7ipk6zeFIHkCdRbtA l1bmAysWFhVCdZgxduTdcpR6V+ieW1mtG3Uu6R/HWml2h5n6YpNMyRFCLsZxZj4z MepGU24u14uG4ZDDDF8SCIihEJryeXxwpoxCKzTWxC2Ix66oIt2hXkCgUggmJ9y+ JZrA/kCsk8/RlP6zvVenJdEIAVzac9WU6w5uQSpjM33qAWHyo2Negw== =jwbT -----END PGP SIGNATURE-----
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