Denial of service via ignored SYN thresholds
Published Mar 31, 2021 · Updated Aug 3, 2024
Denial of service in F5 Networks BIG-IP allows remote attackers to interrupt SNAT listener traffic with a SYN flood. The SNAT listener path ignores configured SYN Check activation thresholds, so SYN cookies do not engage when half-open connections cross the limit. The issue is reachable without authentication only when a vulnerable release processes a SYN flood through an SNAT listener, interrupting availability without reported data exposure or modification.
Summary
What happened
Denial of service in F5 Networks BIG-IP allows remote attackers to interrupt SNAT listener traffic with a SYN flood. The SNAT listener path ignores configured SYN Check activation thresholds, so SYN cookies do not engage when half-open connections cross the limit. The issue is reachable without authentication only when a vulnerable release processes a SYN flood through an SNAT listener, interrupting availability without reported data exposure or modification.
The record
- CVE
- CVE-2021-22998
- Published
- Mar 31, 2021
- Updated
- Aug 3, 2024
- Vendor
- F5 Networks
- Product
- BIG-IP
- Classifications
- T1498
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 31, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, 11.6.x before 11.6.5.3
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo