CVE-2022-26071 in BIG-IP
Summary
by MITRE • 05/05/2022
On F5 BIG-IP 16.1.x versions prior to 16.1.2.2, 15.1.x versions prior to 15.1.5.1, 14.1.x versions prior to 14.1.4.6, 13.1.x versions prior to 13.1.5, and all versions of 12.1.x and 11.6.x, a flaw in the way reply ICMP packets are limited in the Traffic Management Microkernel (TMM) allows an attacker to quickly scan open UDP ports. This flaw allows an off-path remote attacker to effectively bypass source port UDP randomization. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated
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Analysis
by VulDB Data Team • 05/08/2022
The vulnerability identified as CVE-2022-26071 resides within the F5 BIG-IP traffic management microkernel (TMM) and represents a significant weakness in network security controls that affects multiple major versions of the F5 BIG-IP platform. This flaw specifically targets the handling of ICMP reply packets and demonstrates how improper packet processing can undermine fundamental security mechanisms designed to protect network services. The vulnerability impacts F5 BIG-IP systems running versions 16.1.x prior to 16.1.2.2, 15.1.x prior to 15.1.5.1, 14.1.x prior to 14.1.4.6, 13.1.x prior to 13.1.5, and all versions of 12.1.x and 11.6.x, making it a widespread issue affecting the majority of F5 BIG-IP deployments. The flaw operates at the network protocol level and exploits a fundamental weakness in how the system processes ICMP responses, creating an avenue for attackers to circumvent critical security controls.
The technical implementation of this vulnerability stems from inadequate limitations on reply ICMP packet processing within the TMM component, which governs traffic handling in F5 BIG-IP systems. When the system processes ICMP replies, it fails to properly enforce rate limiting or validation controls that should prevent excessive packet generation. This weakness allows an off-path remote attacker to systematically scan UDP ports by sending carefully crafted ICMP packets that trigger responses from the target system. The attack leverages the fact that the system's source port UDP randomization mechanism becomes ineffective, enabling attackers to determine the state of UDP ports without requiring direct access to the network segment. This particular flaw is classified under CWE-284 Access Control Issues, as it represents a failure in properly controlling access to network resources through improper handling of network protocol responses.
The operational impact of CVE-2022-26071 extends far beyond simple port scanning capabilities, as it fundamentally compromises the security posture of affected F5 BIG-IP deployments. An attacker exploiting this vulnerability can effectively bypass source port randomization, a critical security control that randomizes the source port numbers used for outbound connections to make port scanning attacks more difficult. This capability enables comprehensive network reconnaissance without requiring direct network access, allowing attackers to map UDP port configurations across the entire network infrastructure. The vulnerability particularly affects organizations that rely on F5 BIG-IP systems for load balancing, application delivery, and network security, as it undermines the effectiveness of these critical components. The attack can be executed from outside the network perimeter, making it especially dangerous as it allows for passive reconnaissance without the need for active network infiltration.
The threat landscape for this vulnerability aligns with ATT&CK technique T1046 Network Service Scanning, where adversaries attempt to discover open ports and services on target systems. This vulnerability essentially provides a mechanism for attackers to perform rapid UDP port scanning without the normal detection mechanisms that would typically alert administrators to such activities. Security professionals should note that this vulnerability operates at the network infrastructure level, potentially affecting all applications and services that depend on the F5 BIG-IP platform for traffic management and security. The impact is particularly severe for organizations with large network footprints or those that rely heavily on UDP-based services, as the vulnerability enables comprehensive port enumeration that can reveal sensitive information about network architecture and service configurations. Organizations should implement immediate mitigations including applying the vendor patches and monitoring for suspicious ICMP traffic patterns that may indicate exploitation attempts.
Mitigation strategies for CVE-2022-26071 should include immediate deployment of the vendor-provided security patches for all affected versions, as well as network-level controls to monitor and restrict ICMP traffic where possible. Organizations should implement network segmentation to limit the impact of potential exploitation and establish monitoring procedures for unusual ICMP packet patterns that could indicate scanning activities. The vulnerability's exploitation does not require authentication or direct access to the affected systems, making it particularly dangerous for organizations that have not yet patched their deployments. Security teams should also consider implementing intrusion detection systems that can identify the specific packet patterns associated with this vulnerability and establish baseline network behavior to detect anomalous scanning activities. Regular vulnerability assessments should include verification of F5 BIG-IP system patch levels to ensure all affected versions have been properly updated, as this vulnerability can remain undetected for extended periods while providing attackers with valuable reconnaissance information.