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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2019.1779.2 Cisco IOS XR Software Vulnerabilities 11 July 2019 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS XR Software Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2019-1849 CVE-2019-1846 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-iosxr-evpn-dos https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-iosxr-mpls-dos Revision History: July 11 2019: Vendor updated advisory: cisco-sa-20190515-iosxr-evpn-dos May 17 2019: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IOS XR Software BGP MPLS-Based EVPN Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-20190515-iosxr-evpn-dos First Published: 2019 May 15 16:00 GMT Last Updated: 2019 July 10 16:56 GMT Version 1.1: Final Workarounds: No workarounds availableCisco Bug IDs: CSCvk35997 CVE-2019-1849 CWE-754 CVSS Score: 7.4 AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X Summary o A vulnerability in the Border Gateway Protocol (BGP) Multiprotocol Label Switching (MPLS)-based Ethernet VPN (EVPN) implementation of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to a logic error that occurs when the affected software processes specific EVPN routing information. An attacker could exploit this vulnerability by injecting malicious traffic patterns into the targeted EVPN network. A successful exploit could result in a crash of the l2vpn_mgr process on Provider Edge (PE) device members of the same EVPN instance (EVI). On each of the affected devices, a crash could lead to system instability and the inability to process or forward traffic through the device, resulting in a DoS condition that would require manual intervention to restore normal operating conditions. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-20190515-iosxr-evpn-dos Affected Products o Vulnerable Products This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XR Software and are participating in a BGP MPLS-based EVI. Cisco has confirmed that this vulnerability affects both Cisco IOS XR 32-bit Software and Cisco IOS XR 64-bit Software. For information about which Cisco IOS XR Software releases are vulnerable, see the Fixed Software section of this advisory. Determining Whether the Device Has a Vulnerable Configuration There are two methods for determining whether the device has a vulnerable configuration. Option 1: Using the show evpn evi | include EVPN command Administrators can use the show evpn evi | include EVPN command to determine whether the device is participating in a BGP MPLS-based EVI. The following example shows the output of the command for a device that is participating in a BGP MPLS-based EVI: RP/0/0/CPU0:Router#show evpn evi | i EVPN Tue May 14 09:40:09.277 EST VPN-ID Encap Bridge Domain Type ---------- ------ ---------------------------- ------------------- <VPN-ID> MPLS <BD-NAME> EVPN If this command does not exist, or if it produces an output that does not show the string EVPN within the Type column, the device is not affected by the vulnerability described in this advisory. Option 2: Using the show running-config formal l2vpn | include "l2vpn bridge group [^ ]+ bridge-domain [^ ]+ evi [0-9]+" command Administrators can use the show running-config formal l2vpn | include "l2vpn bridge group [^ ]+ bridge-domain [^ ]+ evi [0-9]+" command to determine whether the device is participating in a BGP MPLS-based EVI. The following example shows the output of the command for a device that is participating in a BGP MPLS-based EVI: RP/0/0/CPU0:Router#show running-config formal l2vpn | include "l2vpn bridge group [^ ]+ bridge-domain [^ ]+ evi [0-9]+" l2vpn bridge group bridge-domain evi An empty output of this command indicates that the device is not affected by the vulnerability described in this advisory. Note : Some hardware/software combinations may not support the show running-config formal command. In that case, use the verification step indicated in Option 1. Determining the Cisco IOS XR Software Release To determine which Cisco IOS XR Software release is running on a device and the name of the device on which it is running, administrators can log in to the device and use the show version command in the CLI. If the device is running Cisco IOS XR Software or similar text appears in the system banner. The location and name of the system image file that is currently running on the device appears next to the System image file is text. The name of the hardware product appears on the line after the name of the system image file. The following example shows the output of the show version command on a device that is running Cisco IOS XR Software Release 6.5.2: RP/0/RSP0/CPU0:ASR9001#show version Tue May 14 01:32:32.751 EST Cisco IOS XR Software, Version 6.5.2[Default] Copyright (c) 2019 by Cisco Systems, Inc. ROM: System Bootstrap, Version 2.04(20140227:092320) [ASR9K ROMMON], ASR9001 uptime is 6 hours, 17 minutes System image file is "bootflash:disk0/asr9k-os-mbi-5.3.4.sp4-1.0.0/0x100000/mbiasr9k-rp.vm" cisco ASR9K Series (P4040) processor with 8388608K bytes of memory. P4040 processor at 1500MHz, Revision 2.0 ASR-9001 Chassis 2 Management Ethernet 8 TenGigE 20 GigabitEthernet 8 DWDM controller(s) 8 WANPHY controller(s) 44 GigabitEthernet/IEEE 802.3 interface(s) 219k bytes of non-volatile configuration memory. 2880M bytes of hard disk. 3932144k bytes of disk0: (Sector size 512 bytes). Configuration register on node 0/RSP0/CPU0 is 0x2102 Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability. No other Cisco products are currently known to be affected by this vulnerability. Cisco has confirmed that this vulnerability does not affect devices running Cisco IOS Software, Cisco IOS XE Software, or Cisco NX-OS Software. Details o EVPN is a next-generation solution that provides Ethernet multipoint services over MPLS networks. In EVPN, customers' MAC addresses are used as routable addresses. PE devices participating in an EVI use Multiprotocol BGP (MP-BGP) as a route learning and distribution mechanism. The vulnerability is due to a logic error that occurs when the affected software processes specific MP-BGP EVPN update messages. An attacker that controls multiple Customer Edge (CE) devices could exploit this vulnerability by injecting malicious traffic patterns into the EVPN network. An exploit could cause the Provider Edge (PE) device to advertise specific MP-BGP EVPN update messages that could result in a crash of the l2vpn_mgr process on PE device members of the same EVI. Indicators of Compromise o Exploitation of this vulnerability could cause the affected device to repeatedly generate an error message similar to the following: RP/0/RP0/CPU0:May 14 15:41:03.241 IST: syslog_dev[117]: l2vpn_mgr[1265] PID-8642: l2vpn/evpn/include/evpn_label_db_defs.h: 412 FALSE -- assertion failed Customers are advised to contact their support organization to review the error message and determine whether the device has been affected by exploitation of this vulnerability. Workarounds o There are no workarounds that address this vulnerability. Fixed Software o Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license: https://www.cisco.com/c/en/us/products/end-user-license-agreement.html Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades. When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page , to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers. Customers Without Service Contracts Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Fixed Releases The following table lists major software release trains of Cisco IOS XR Software, indicates whether a release train is affected by the vulnerabilities described in this advisory, and the first minor release that includes the fix for these vulnerabilities, if applicable. Customers should migrate to an appropriate release as indicated in the following table: Software Train First Fixed Release Recommended Release 4.3 Not vulnerable Not vulnerable 5.0 Not vulnerable Not vulnerable 5.1 Not vulnerable Not vulnerable 5.2 Not vulnerable Not vulnerable 5.3 Not vulnerable Not vulnerable 6.0 Not vulnerable Not vulnerable 6.1 6.5.3 6.5.3 6.2 6.5.3 6.5.3 6.3 6.3.3 6.3.3 6.4 6.4.2 6.4.2 6.5 6.5.2 6.5.3 6.6 6.6.1 6.6.12 Cisco has also released a software maintenance upgrade (SMU) for Cisco Aggregation Services Router (ASR) 9000 Series that addresses this vulnerability. +--------------+-------+-------------------------+ |IOS XR Release|SMU ID |ASR 9000 SMU Name | +--------------+-------+-------------------------+ |6.2.3 |AA15558|asr9k-px-6.2.3.CSCvk35997| +--------------+-------+-------------------------+ The SMU/service pack can be downloaded from the Software Center on Cisco.com. Exploitation and Public Announcements o The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. Source o This vulnerability was found during internal security testing. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-20190515-iosxr-evpn-dos Revision History o +---------+-----------------------+---------------+--------+--------------+ | Version | Description | Section | Status | Date | +---------+-----------------------+---------------+--------+--------------+ | 1.1 | Added SMU | Fixed | Final | 2019-July-10 | | | information. | Software | | | +---------+-----------------------+---------------+--------+--------------+ | 1.0 | Initial public | - | Final | 2019-May-15 | | | release. | | | | +---------+-----------------------+---------------+--------+--------------+ - ------------------------------------------------------------------------------- Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers MPLS OAM Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-20190515-iosxr-mpls-dos First Published: 2019 May 15 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvk63685 CVE-2019-1846 CWE-20 CVSS Score: 7.4 AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X Summary o A vulnerability in the Multiprotocol Label Switching (MPLS) Operations, Administration, and Maintenance (OAM) implementation of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to the incorrect handling of certain MPLS OAM packets. An attacker could exploit this vulnerability by sending malicious MPLS OAM packets to an affected device. A successful exploit could allow the attacker to cause the lspv_server process to crash. The crash could lead to system instability and the inability to process or forward traffic though the device, resulting in a DoS condition that require manual intervention to restore normal operating conditions. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-20190515-iosxr-mpls-dos Affected Products o Vulnerable Products This vulnerability affects Cisco Aggregation Services Router (ASR) 9000 Series when the following conditions are met: The router is running Cisco IOS XR Software Release 5.3.3 Service Pack 10. The router has the MPLS OAM feature configured. For information about which Cisco IOS XR Software releases are vulnerable, see the Fixed Software section of this advisory. Determining Whether MPLS OAM Is Configured Administrators can use the show running-config mpls oam command to determine whether MPLS OAM is enabled. The following example shows the output of the command for a device that has the MPLS OAM feature enabled: RP/0/RSP0/CPU0:ASR9001#show running-config mpls oam Tue Feb 19 12:45:37.011 UTC mpls oam An empty output of this command indicates that the device is not affected by the vulnerability described in this advisory. Determining the Cisco IOS XR Software Release To determine which Cisco IOS XR Software release is running on a device and the name of the device on which it is running, administrators can log in to the device and use the show version command in the CLI. If the device is running Cisco IOS XR Software, Cisco IOS XR Software or similar text appears in the system banner. The location and name of the system image file that is currently running on the device appears next to the System image file is text. The name of the hardware product appears on the line after the name of the system image file. The following example shows the output of the show version command on a device that is running Cisco IOS XR Software release 5.3.3 Service Pack 10 : RP/0/RSP0/CPU0:ASR9001#show version Wed Jan 24 01:32:32.751 EST Cisco IOS XR Software, Version 5.3.3[Default] Copyright (c) 2017 by Cisco Systems, Inc. ROM: System Bootstrap, Version 2.04(20140227:092320) [ASR9K ROMMON], ASR9001 uptime is 6 hours, 17 minutes System image file is "bootflash:disk0/asr9k-os-mbi-5.3.3.sp10-1.0.0/0x100000/mbiasr9k-rp.vm" cisco ASR9K Series (P4040) processor with 8388608K bytes of memory. P4040 processor at 1500MHz, Revision 2.0 ASR-9001 Chassis 2 Management Ethernet 8 TenGigE 20 GigabitEthernet 8 DWDM controller(s) 8 WANPHY controller(s) 44 GigabitEthernet/IEEE 802.3 interface(s) 219k bytes of non-volatile configuration memory. 2880M bytes of hard disk. 3932144k bytes of disk0: (Sector size 512 bytes). Configuration register on node 0/RSP0/CPU0 is 0x2102 Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability. Cisco has determined that this vulnerability does not affect Cisco Aggregation Services Router (ASR) 9000 Series that are not running Cisco IOS XR Software Release 5.3.3 Service Pack 10 or that have not enabled the MPLS OAM feature. Note : The MPLS OAM feature is not enabled by default on Cisco XR Software. No other devices running Cisco IOS XR Software are affected. Cisco has also confirmed that this vulnerability does not affect devices running Cisco IOS Software, Cisco IOS XE Software, or Cisco NX-OS Software. Details o The MPLS OAM feature helps service providers monitor label-switched paths (LSPs) and quickly isolate MPLS forwarding problems to assist with fault detection and troubleshooting in an MPLS network. The vulnerability is due to the incorrect handling of certain MPLS OAM packets. An attacker could exploit this vulnerability by sending malicious MPLS OAM packets to an affected device. To exploit this vulnerability, an attacker must have access to the same MPLS domain as the targeted device, which must be configured to process MPLS OAM packets. An exploitation of this vulnerability could cause the lspv_server process to crash, which could result in a DoS condition requiring manual intervention to recover. Indicators of Compromise o Exploitation of this vulnerability could cause the affected device to generate an error message similar to the following: #RP/0/RSP0/CPU0:May 14 01:44:57.911 : dumper[60]: %OS-DUMPER-7 DUMP_REQUEST : Dump request for process pkg/bin/lspv_server RP/0/RSP0/CPU0:May 14 01:44:57.913 : dumper[60]: %OS-DUMPER-7-DUMP_ATTRIBUTE : Dump request with attribute 7 for process pkg/bin/lspv_server RP/0/RSP0/CPU0:May 14 01:44:57.913 : dumper[60]: %OS-DUMPER-4-CRASH_INFO : Crashed pid = 561506 (pkg/bin/lspv_server) Customers are advised to contact their support organization to review the error message and determine whether the device has been affected by exploitation of this vulnerability. Workarounds o There are no workarounds that address this vulnerability. Disabling the MPLS OAM feature eliminates the exploit vector. Administrators can disable the MPLS OAM feature by using the no mpls oam command in global configuration mode. This action may be a suitable mitigation until devices that are affected by this vulnerability can be upgraded. Fixed Software o Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license: https://www.cisco.com/c/en/us/products/end-user-license-agreement.html Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades. When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page , to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers. Customers Without Service Contracts Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Fixed Releases Cisco has released a software maintenance upgrade (SMU) for Cisco Aggregation Services Router (ASR) 9000 Series that addresses this vulnerability. The fix has also been incorporated into Service Pack 11 for Cisco IOS XR Software Release 5.3.3. IOS XR Release SMU ID ASR 9000 SMU Name 5.3.3 AA14582 asr9k-px-5.3.3.CSCvk63685 The SMU/service pack can be downloaded from the Software Center on Cisco.com. Exploitation and Public Announcements o The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. Source o This vulnerability was found during the resolution of a Cisco TAC support case. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-20190515-iosxr-mpls-dos Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2019-May-15 | +----------+---------------------------+----------+--------+--------------+ - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. 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On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBXSak62aOgq3Tt24GAQiqwhAA24yxwyM1mgRwaSE7shzUWIX47NgLQy3J yllr0sBQbDKmTOvkOhGTT83wEnoypOpUrRLVaLd/G0gcZXrnWRABq0r7zNgoNPrM d8yppBlWzkFRAw0IKp0gGp0DZk2NTWnyf89nH00Yl4w1BaESwggej0OcEsC9E5VA EXIt0BuPqlkW84JYWaTPxHjNEkr2jIf3BN5g+fr70+YCI/ja1v0HA2QlRzFtpQti 9DAIM7N/bLhGmyk8+kIDqjIO2lfKLWcf8wsJUNE3g/0GV+ZRf/xHi2dhf8KUSjEO DKiBfvgl0vwWOp7WO5AtJcA2/BDI5q6MVwuJDFFNX+vTWANWN/GfdVbTo883zGOZ n9Lys/yb9X7cwK3HzFmdQXsfE2MsY6f3PQnblOTHRb/SqG3a2rxseoCEprwqFfVt WLIl9pNO9ryfCq+zIXxNeQTSVqxvOjadnrvF97KbwqeAkRXHW4Fs9/HTtbKF70Jp +pAKsjQoirsVt9kKG+bQBlW9S20zbrg/o7D1N0TvtoiFlo3l0HJWpvMfReORgJZB yWIuiDWu0iQaujeVzFNJ8g5VfsiIS2NZx0pPiHa1t1TptO+O630cOKGUTSZEwbNv 902jcsA1NvEALrzFZ+qPM2P/8XwVIx3tPntKJzzE5O+GxWPmP1ZQTxltdQRp0Nmg ddhPHlPgl8k= =f3nI -----END PGP SIGNATURE-----