CVE-2020-27718 : Security Advisory and Response
Learn about CVE-2020-27718, a vulnerability in BIG-IP ASM & Advanced WAF versions that can lead to high CPU usage when processing JSON payloads. Find mitigation steps and patching recommendations here.
A vulnerability in BIG-IP ASM & Advanced WAF versions could lead to excessive CPU usage when processing requests with JSON payloads.
Understanding CVE-2020-27718
What is CVE-2020-27718?
When specific versions of BIG-IP ASM & Advanced WAF process requests with JSON payloads containing a large number of parameters, it can result in high CPU consumption in the BIG-IP ASM bd process.
The Impact of CVE-2020-27718
This vulnerability could be exploited to cause a Denial of Service (DoS) condition on affected systems.
Technical Details of CVE-2020-27718
Vulnerability Description
The vulnerability arises from the excessive CPU usage triggered by processing JSON payloads with numerous parameters.
Affected Systems and Versions
- Products: BIG-IP ASM & Advanced WAF
- Versions: 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, 13.1.0-13.1.3.4, 12.1.0-12.1.5.2, 11.6.1-11.6.5.2
Exploitation Mechanism
The vulnerability can be exploited by sending crafted JSON payloads with an excessive number of parameters, leading to CPU exhaustion.
Mitigation and Prevention
Immediate Steps to Take
- Monitor CPU usage for abnormal spikes
- Implement rate limiting for JSON requests
- Apply vendor-supplied patches or updates
Long-Term Security Practices
- Regularly update and patch systems
- Conduct security assessments and audits
Patching and Updates
Apply the necessary patches provided by F5 to address the vulnerability.