CVE-2023-38802 PAN-OS: Denial-of-Service (DoS) Vulnerability in BGP Software

Description

BGP software such as FRRouting FRR included as part of the PAN-OS, Prisma SD-WAN ION, and Prisma Access routing features enable a remote attacker to incorrectly reset network sessions though an invalid BGP update. This issue is applicable only to devices and appliances with BGP routing features enabled.

This issue requires the remote attacker to control at least one established BGP session that is propagated to the router to exploit it. The denial-of-service (DoS) impact on the network is dependent on the network's architecture and fault tolerant design.

Prisma Access ‘Security Processing Node Endpoint Remote Network (SP-RN/Branches)' and 'Service Connections (SCs/CANs)' nodes do not peer with the Internet and do not receive Internet routes directly unless explicitly configured by the customer. Prisma Access Nodes are commonly protected by unaffected customer-premise equipment (CPE router devices). Hence the impact of this issue on Prisma Access is limited.

Further details about this issue can be found at: https://blog.benjojo.co.uk/post/bgp-path-attributes-grave-error-handling

Product Status

Required Configuration for Exposure

This issue is applicable only to devices and appliances that are configured with BGP routing features enabled. You can verify whether BGP is enabled for a router by selecting it from 'Network > Virtual Routers’ or 'Network > Logical Routers’ in the web interface of PAN-OS firewalls.

To exploit this issue, the remote attacker must control at least one established BGP session that is propagated to the router.

Severity: HIGH

CVSSv4.0 Base Score: 8.2 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/AU:Y/R:A/V:C/RE:L/U:Amber)

Exploitation Status

Palo Alto Networks is not aware of any malicious exploitation of this issue targeting our customers. However, knowledge of invalid BGP attributes that trigger this issue is publicly available.

Weakness Type

CWE-754 Improper Check for Unusual or Exceptional Conditions

Solution

This issue is fixed in PAN-OS 8.1.26, PAN-OS 9.0.17-h4, PAN-OS 9.1.16-h3, PAN-OS 10.1.11, PAN-OS 10.2.6, PAN-OS 11.0.3, and all later PAN-OS versions.

This issue is fixed in Prisma SD-WAN ION 6.1.5, Prisma SD-WAN ION 6.2.3, and all later Prisma SD-WAN ION versions. This issue does not impact Prisma SD-WAN ION 5.6 versions.

For Prisma Access customers, the upgrade to fix this issue will be available on 09/30. Customers should work with their Prisma Access contacts and support to secure a maintenance window for the on-demand software upgrade.

Please note that full Prisma Access data plane upgrades scheduled on and after 09/30 will have this fix incorporated by default. No additional action is necessary for these customers to remediate this issue.

Workarounds and Mitigations

You can prevent exploitation of this issue by inserting an unaffected BGP router—configured to drop the invalid BGP update instead of propagating it—between the attacker-originated BGP update and PAN-OS, Prisma SD-WAN ION, and Prisma Access devices. This stops the invalid BGP update from reaching the affected router.

Acknowledgments

Frequently Asked Questions

Q.Is this issue related to BGP routing CVEs CVE-2023-4481, CVE-2023-38283, and CVE-2023-40457?

Yes. As per the CVE assignment rules, each independent implementation codebase would be assigned a CVE if there is a problem in the implementation of a standard.

This issue has been assigned the following CVE IDs: CVE-2023-38802 for FRR, CVE-2023-38283 for OpenBGPd, CVE-2023-40457 for EXOS, and CVE-2023-4481 for JunOS.

Timeline