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CVE-2022-0028

HIGH
Published 2022-08-10T16:00:16.743Z
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CVSS Score

V3.1
8.6
/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Base Score Metrics
Exploitability: N/A Impact: N/A

EPSS Score

v2025.03.14
0.054
probability
of exploitation in the wild

There is a 5.4% chance that this vulnerability will be exploited in the wild within the next 30 days.

Updated: 2025-06-25
Exploit Probability
Percentile: 0.897
Higher than 89.7% of all CVEs

Attack Vector Metrics

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED

Impact Metrics

Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Description

A 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 source zone that has an external facing 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 software updates for this issue are expected to be released no later than the week of August 15, 2022. 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.

Understanding This Vulnerability

This Common Vulnerabilities and Exposures (CVE) entry provides detailed information about a security vulnerability that has been publicly disclosed. CVEs are standardized identifiers assigned by MITRE Corporation to track and catalog security vulnerabilities across software and hardware products.

The severity rating (HIGH) indicates the potential impact of this vulnerability based on the CVSS (Common Vulnerability Scoring System) framework. Higher severity ratings typically indicate vulnerabilities that could lead to more significant security breaches if exploited. Security teams should prioritize remediation efforts based on severity, exploit availability, and the EPSS (Exploit Prediction Scoring System) score, which predicts the likelihood of exploitation in the wild.

If this vulnerability affects products or systems in your infrastructure, we recommend reviewing the affected products section, checking for available patches or updates from vendors, and implementing recommended workarounds or solutions until a permanent fix is available. Organizations should also monitor security advisories and threat intelligence feeds for updates about active exploitation of this vulnerability.

Available Exploits

No exploits available for this CVE.

Related News

No news articles found for this CVE.

Affected Products

References

Workarounds

If you have a URL filtering policy with one or more blocked categories assigned to a source zone that has an external facing network 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:
1. It is not necessary nor advantageous to apply both the attack and flood protections.
2. (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

Solutions

We 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

We intend to fix this issue for PA-Series, VM-Series and CN-Series firewalls with a fix in the following PAN-OS software releases: PAN-OS 8.1.23-h1 (ETA: week of August 8, 2022), PAN-OS 9.0.16-h3 (ETA: week of August 15, 2022), PAN-OS 9.1.14-h4 (ETA: week of August 15, 2022), PAN-OS 10.0.11-h1 (ETA: week of August 15, 2022), PAN-OS 10.1.6-h6 (ETA: week of August 8, 2022), and PAN-OS 10.2.2-h2 (ETA: week of August 15, 2022).

We expect to release all PAN-OS software updates for this issue no later than the week of August 15, 2022.

Credits & Acknowledgments

Palo Alto Networks thanks CERT-XLM for reporting this issue.

Timeline

Initial publication

Known Exploited Vulnerability

This vulnerability is actively being exploited in the wild

View KEV Details

Remediation Status

Overdue

Due Date

September 12, 2022

Added to KEV

August 22, 2022

Required Action

Apply updates per vendor instructions.

Affected Product

Vendor/Project: Palo Alto Networks
Product: PAN-OS

Ransomware Risk

Known Ransomware Use
KEV Catalog Version: 2025.01.24 Released: January 24, 2025

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

⚠ Unreviewed HIGH

GHSA-r3j6-h9rm-9q33

Advisory Details

A 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 source zone that has an external facing 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 software updates for this issue are expected to be released no later than the week of August 15, 2022. 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.

CVSS Scoring

CVSS Score

7.5

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Advisory provided by GitHub Security Advisory Database. Published: August 11, 2022, Modified: October 22, 2025

References

Published: 2022-08-10T16:00:16.743Z
Last Modified: 2025-07-28T19:45:10.743Z
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