Summary

• Multiple vulnerabilities in Cisco SD-WAN products could allow an unauthenticated, remote attacker to execute denial of service (DoS) attacks against an affected device.

  For more information about these vulnerabilities, see the Details section of this advisory.

  Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-dosmulti-48jJuEUP

Affected Products

• Vulnerable Products

  These vulnerabilities may affect the following Cisco products if they are running a vulnerable release of Cisco SD-WAN Software:

  • IOS XE SD-WAN Software
  • SD-WAN vBond Orchestrator Software
  • SD-WAN vEdge Cloud Routers
  • SD-WAN vEdge Routers
  • SD-WAN vManage Software
  • SD-WAN vSmart Controller Software

  See the Details section of this advisory for information on vulnerable products for each vulnerability.

  For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.

  Cisco has confirmed that these vulnerabilities do not affect Cisco IOS XE universal image releases 17.2.1r and later.

Details

• The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit the other vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerability.

  Details about the vulnerabilities are as follows.

  CVE-2021-1241: Cisco SD-WAN vEdge Router VPN Denial of Service Vulnerability

  A vulnerability in VPN tunneling features of Cisco SD-WAN vEdge Routers could allow an unauthenticated, remote attacker to cause a DoS condition on an affected system.

  The vulnerability is due to insufficient handling of malformed packets. An attacker could exploit this vulnerability by sending crafted packets through an affected device. A successful exploit could allow the attacker to cause the device to reboot, resulting in a DoS condition on the affected system.

  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

  Bug ID(s): CSCvu31763
  CVE ID: CVE-2021-1241
  Security Impact Rating (SIR): High
  CVSS Base Score: 8.6
  CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

  CVE-2021-1273: Cisco SD-WAN IPSec Denial of Service Vulnerability

  A vulnerability in the IPSec tunnel management of Cisco SD-WAN vBond Orchestrator Software, Cisco SD-WAN vEdge Cloud Routers, Cisco SD-WAN vEdge Routers, Cisco SD-WAN vManage Software, and Cisco SD-WAN vSmart Controller Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected system.

  The vulnerability is due to the bounds checking in the forwarding plane of the IPSec tunnel management functionality. An attacker could exploit this vulnerability by sending crafted IPv4 or IPv6 packets to a specific device. A successful exploit could allow the attacker to cause a DoS condition on the affected system.

  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

  Bug ID(s): CSCvu28409
  CVE ID: CVE-2021-1273
  Security Impact Rating (SIR): High
  CVSS Base Score: 8.6
  CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

  CVE-2021-1274: Cisco SD-WAN UDP Denial of Service Vulnerability

  A vulnerability in the UDP connection response of Cisco IOS XE SD-WAN, Cisco SD-WAN vBond Orchestrator Software, Cisco SD-WAN vEdge Cloud Routers, Cisco SD-WAN vEdge Routers, Cisco SD-WAN vManage Software, and Cisco SD-WAN vSmart Controller Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected system.

  The vulnerability is due to the presence of a null dereference in vDaemon. An attacker could exploit this vulnerability by sending crafted traffic to a specific device. A successful exploit could allow the attacker to cause a DoS condition on the affected system.

  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

  Bug ID(s): CSCvt11523
  CVE ID: CVE-2021-1274
  Security Impact Rating (SIR): High
  CVSS Base Score: 8.6
  CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

  CVE-2021-1278: Cisco SD-WAN Denial of Service Vulnerabilities

  Multiple vulnerabilities in the symbolic link (symlink) creation functionality of Cisco SD-WAN vBond Orchestrator Software, Cisco SD-WAN vEdge Cloud Routers, Cisco SD-WAN vEdge Routers, Cisco SD-WAN vManage Software, and Cisco SD-WAN vSmart Controller Software could allow an authenticated, local attacker to overwrite arbitrary files that are owned by the root user on the affected system.

  These vulnerabilities are due to the absence of validation checks for the input that is used to create symlinks. An attacker could exploit these vulnerabilities by creating a symlink to a target file on a specific path. A successful exploit could allow the attacker to corrupt the contents of the file. If the file is a critical systems file, the exploit could lead to a DoS condition on an affected system. To exploit these vulnerabilities, the attacker would need to have valid credentials on the system.

  Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

  Bug ID(s): CSCvt11522, CSCvt11530
  CVE ID: CVE-2021-1278
  Security Impact Rating (SIR): Medium
  CVSS Base Score: 6.7
  CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:H

  CVE-2021-1279: Cisco SD-WAN SNMPv3 Denial of Service Vulnerability

  A vulnerability in the SNMPv3 management feature of Cisco SD-WAN vBond Orchestrator Software, Cisco SD-WAN vEdge Cloud Routers, Cisco SD-WAN vEdge Routers, Cisco SD-WAN vManage Software, and Cisco SD-WAN vSmart Controller Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected system.

  The vulnerability is due to insufficient input validation for the SNMPv3 management functionality. An attacker could exploit this vulnerability by sending crafted SNMPv3 traffic to a specific device. A successful exploit could allow the attacker to cause a DoS condition on the affected system.

  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

  Bug ID(s): CSCvq20708
  CVE ID: CVE-2021-1279
  Security Impact Rating (SIR): Medium
  CVSS Base Score: 5.3
  CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Workarounds

• There are no workarounds that address these vulnerabilities.

Fixed Software

• Cisco has released free software updates that address the vulnerabilities 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 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

  Customers are advised to upgrade to an appropriate fixed software release as indicated in the following table(s). To ensure a complete upgrade solution, consider that this advisory is part of a collection that includes the following advisories:

  • cisco-sa-sdwan-abyp-TnGFHrS: Cisco SD-WAN vManage Authorization Bypass Vulnerabilities
  • cisco-sa-sdwan-bufovulns-B5NrSHbj: Cisco SD-WAN Buffer Overflow Vulnerabilities
  • cisco-sa-sdwan-cmdinjm-9QMSmgcn: Cisco SD-WAN Command Injection Vulnerabilities
  • cisco-sa-sdwan-dosmulti-48jJuEUP: Cisco SD-WAN Denial of Service Vulnerabilities

  SD-WAN Software

  Cisco SD-WAN Releases	First Fixed Release for These Vulnerabilities	First Fixed Release for All Vulnerabilities Described in This Collection of Advisories
  Earlier than 18.3	Migrate to a fixed release.	Migrate to a fixed release.
  18.3	Migrate to a fixed release.	Migrate to a fixed release.
  18.4	18.4.6	Migrate to a fixed release.
  19.2	19.2.4	Migrate to a fixed release.
  19.3	Migrate to a fixed release.	Migrate to a fixed release.
  20.1	20.1.2	Migrate to a fixed release.
  20.3	20.3.1	20.3.2
  20.4	20.4.1	20.4.1

  IOS XE SD-WAN Software

  Cisco IOS XE SD-WAN Releases	First Fixed Release for These Vulnerabilities	First Fixed Release for All Vulnerabilities Described in This Collection of Advisories
  16.9	Migrate to a fixed release.	Migrate to a fixed release.
  16.10	Migrate to a fixed release.	Migrate to a fixed release.
  16.11	Migrate to a fixed release.	Migrate to a fixed release.
  16.12	16.12.4	16.12.4

Exploitation and Public Announcements

• The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

Source

• CVE-2021-1273: This vulnerability was found by Joseph Connor of Cisco during internal security testing.

  CVE-2021-1274: This vulnerability was found by Arthur Vidineyev of Cisco during internal security testing.

  CVE-2021-1278: This vulnerability was found by Andrew Kim of Cisco during internal security testing.

  CVE-2021-1279: This vulnerability was found during internal security testing.

  CVE-2021-1241: This vulnerability were found during the resolution of a Cisco TAC support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-dosmulti-48jJuEUP

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated Fixed Releases.	Fixed Software	Final	2021-FEB-02
  1.0	Initial public release.	—	Final	2021-JAN-20

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