Palo Alto Networks Security Advisories / CVE-2022-0028 Show
Attack Vector NETWORK Scope CHANGED Attack Complexity LOW Confidentiality Impact NONE Privileges Required NONE Integrity Impact NONE User Interaction NONE Availability Impact HIGH NVD JSON Published 2022-08-10 Updated 2022-08-19 Reference PAN-192999 Discovered externally DescriptionA PAN-OS URL filtering policy misconfiguration could allow a network-based attacker to conduct reflected and amplified TCP denial-of-service (RDoS) attacks. The DoS attack would appear to originate from a Palo Alto Networks PA-Series (hardware), VM-Series (virtual) and CN-Series (container) firewall against an attacker-specified target. To be misused by an external attacker, the firewall configuration must have a URL filtering profile with one or more blocked categories assigned to a security rule with a source zone that has an external facing network interface. This configuration is not typical for URL filtering and, if set, is likely unintended by the administrator. If exploited, this issue would not impact the confidentiality, integrity, or availability of our products. However, the resulting denial-of-service (DoS) attack may help obfuscate the identity of the attacker and implicate the firewall as the source of the attack. We have taken prompt action to address this issue in our PAN-OS software. All PAN-OS software updates for this issue are now available. This issue does not impact Panorama M-Series or Panorama virtual appliances. This issue has been resolved for all Cloud NGFW and Prisma Access customers and no additional action is required from them. Product Status
Required Configuration for ExposureThe firewall configuration must have a URL filtering profile with one or more blocked categories assigned to a security rule with a source zone that has an external facing interface for this issue to be misused by an external attacker. This configuration is not typical for URL filtering and is likely unintended by the administrator. This issue is applicable to PA-Series (hardware), VM-Series (virtual), and CN-Series (container) firewalls only when all three of the following conditions are true: 1. The security policy on the firewall that allows traffic to pass from Zone A to Zone B includes a URL filtering profile with one or more blocked categories; AND 2. Packet-based attack protection is not enabled in a Zone Protection profile for Zone A including both (Packet Based Attack Protection > TCP Drop > TCP Syn With Data) and (Packet Based Attack Protection > TCP Drop > Strip TCP Options > TCP Fast Open); AND 3. Flood protection through SYN cookies is not enabled in a Zone Protection profile for Zone A (Flood Protection > SYN > Action > SYN Cookie) with an activation threshold of 0 connections. Severity:HIGHCVSSv3.1 Base Score:8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) Exploitation StatusPalo Alto Networks recently learned that an attempted reflected denial-of-service (RDoS) attack was identified by a service provider. This attempted attack took advantage of susceptible firewalls from multiple vendors, including Palo Alto Networks. We immediately started to root cause and remediate this issue. Exploitation of this issue does not impact the confidentiality, integrity, or availability of our products. Weakness TypeCWE-406 Insufficient Control of Network Message Volume (Network Amplification) SolutionWe identified workarounds to prevent the denial-of-service (DoS) attacks that result from this issue in certain Palo Alto Networks firewalls, with this policy configuration. This issue is fixed in PAN-OS 8.1.23-h2, PAN-OS 9.0.16-h3, PAN-OS 9.1.14-h4, PAN-OS 10.0.11-h2, PAN-OS 10.1.6-h6, PAN-OS 10.2.2-h2, and all later PAN-OS versions for PA-Series, VM-Series and CN-Series firewalls. All PAN-OS software updates for this issue are now available. Workarounds and MitigationsIf you have a URL filtering policy with one or more blocked categories assigned to a security rule with a source zone that has an external facing interface, removing this configuration will prevent this issue from being exploited by remote attackers to conduct reflected DoS. To prevent denial-of-service (DoS) attacks resulting from this issue from all sources, you can configure your Palo Alto Networks firewalls by enabling one of two zone protection mitigations on all Security zones with an assigned Security policy that includes a URL filtering profile: 1. Packet-based attack protection including both (Packet Based Attack Protection > TCP Drop > TCP SYN with Data) and (Packet Based Attack Protection > TCP Drop > Strip TCP Options > TCP Fast Open); OR 2. Flood protection (Flood Protection > SYN > Action > SYN Cookie) with an activation threshold of 0 connections. NOTES: It is not necessary nor advantageous to apply both the attack and flood protections. (Palo Alto Networks Aporeto software only) You should not enable either of these protections if using Aporeto software; instead, wait for and install a fixed version of PAN-OS software. Packet-Based Attack Protection Workaround (Recommended) Follow the technical documentation to configure packet-based attack protection options for all defined Security zones with URL filtering enabled in the Security profile for that zone: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/zone-protection-and-dos-protection/configure-zone-protection-to-increase-network-security/configure-packet-based-attack-protection The packet-based attack protection workaround will prevent the firewall from establishing TCP sessions in impacted zones when the TCP SYN packet contains data in the three-way handshake for a TCP session. Please note that this workaround may disrupt applications that use TCP Fast Open in the zone. Flood Protection (Alternate) Workaround If you instead decide to enable the flood protection workaround, first make sure you understand how enabling SYN cookies will change traffic flow in the impacted zones: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/zone-protection-and-dos-protection/zone-defense/zone-protection-profiles/flood-protection AcknowledgmentsThis issue was responsibly reported to Palo Alto Networks by Excellium-Services S.A. CSIRT, CERT-XLM. Frequently Asked QuestionsQ. How is this a high severity vulnerability if it does not impact the security of the firewall?
Q. Why is this considered a misconfiguration or unintended configuration?
Q. Why is this fixed with software updates if this is due to a misconfiguration?
Q. How do I know if my firewall(s) are being misused for conducting DoS attacks?
Timeline2022-08-19 PAN-OS 9.0.16-h3, PAN-OS 9.1.14-h4, and PAN-OS 10.0.11-h2 fixed versions are now available. 2022-08-18 PAN-OS 10.2.2-h2 fixed version is now available. 2022-08-16 PAN-OS 8.1.23-h2 fixed version is now available. 2022-08-12 An update to the acknowledgements section of the advisory. 2022-08-10 PAN-OS 10.1.6-h6 fixed version is now available. Updated ETA for PAN-OS 8.1.23-h2. Clarified URL filtering assignment language. 2022-08-10 Initial publication What is the HTTP method that retrieves data by URL?The GET method is used to retrieve information from the given server using a given URI. Requests using GET should only retrieve data and should have no other effect on the data.
What is the passive process of finding information on a company's network?Passive Footprinting is the process of gathering information on a target by innocuous, or, passive, means. Browsing the target's website, visiting social media profiles of employees, searching for the website on WHOIS, and performing a Google search of the target are all ways of passive Footprinting.
Which HTTP method requests that the entity is stored under the request URI?The PUT method requests that the enclosed entity be stored under the supplied Request-URI. If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server.
Which of the following is a text file generated by a web server and stored on a users browser?A "cookie" is a small text file containing information, generated by a web site's server and placed on a user's-visitor's personal computer or smart device.
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