CVE-2020-5929

high-risk

Published 2020-09-25

In versions 13.0.0-13.0.0 HF2, 12.1.0-12.1.2 HF1, and 11.6.1-11.6.2, BIG-IP platforms with Cavium Nitrox SSL hardware acceleration cards, a Virtual Server configured with a Client SSL profile, and using Anonymous (ADH) or Ephemeral (DHE) Diffie-Hellman key exchange and Single DH use option not enabled in the options list may be vulnerable to crafted SSL/TLS Handshakes that may result with a PMS (Pre-Master Secret) that starts in a 0 byte and may lead to a recovery of plaintext messages as BIG-IP TLS/SSL ADH/DHE sends different error messages acting as an oracle. Similar error messages when PMS starts with 0 byte coupled with very precise timing measurement observation may also expose this vulnerability.

Do I need to act?

0.67% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 5.9/10 Medium

NETWORK / HIGH complexity

Affected Products (20)

Big-Ip Access Policy Manager

Big-Ip Advanced Firewall Manager

Big-Ip Advanced Web Application Firewall

Affected Vendors

References (2)

Vendor Advisory https://support.f5.com/csp/article/K91158923

/ 100

high-risk

Severity 18/34 · Moderate

Exploitability 2/34 · Minimal

Exposure 30/34 · Critical