CVE-2018-5743 Limiting simultaneous TCP clients was ineffective

What is CVE-2018-5743?

CVE-2018-5743 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 9 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.

Weakness: CWE-770

Which versions are affected by CVE-2018-5743?

It affects 17 products.

Products include F5 Big-Ip Access Policy Manager, F5 Big-Ip Advanced Firewall Manager, F5 Big-Ip Analytics, F5 Big-Ip Application Acceleration Manager, F5 Big-Ip Application Security Manager, F5 Big-Ip Domain Name System and 11 more.

How do I fix CVE-2018-5743?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2018-5743 being exploited?

There is no known exploitation of CVE-2018-5743 in the wild and no public exploit code.

Other vulnerabilities in F5 Big-Ip Access Policy Manager

• CVE-2023-46747 F5 BIG-IP Configuration Utility Authentication Bypass Exploited Critical 9.8
• CVE-2022-1388 F5 BIG-IP Missing Authentication Exploited Critical 9.8
• CVE-2021-22986 F5 BIG-IP and BIG-IQ Centralized Management iControl REST Remote Code Execution Exploited Critical 9.8
• CVE-2021-22991 F5 BIG-IP Traffic Management Microkernel Buffer Overflow Exploited Critical 9.8
• CVE-2020-5902 F5 BIG-IP Traffic Management User Interface (TMUI) Remote Code Execution Exploited Critical 9.8

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2018-5743, DEBIAN-CVE-2018-5743, DLA-1859-1, GHSA-3cr4-c5wq-3ccv, RHSA-2019:1145, RHSA-2019:1294 and 6 more.