PT-2020-18827 · F5 · F5 Big-Ip

Published 2020-09-25 · Updated 2024-03-27 · CVE-2020-5929

Positive Technologies (AI Summary)

CVSS v3.1

5.9

Medium

Base vector

AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Name of the Vulnerable Software and Affected Versions F5 BIG-IP versions 11.6.1 through 11.6.2 F5 BIG-IP versions 12.1.0 through 12.1.2 HF1 F5 BIG-IP versions 13.0.0 through 13.0.0 HF2

Description The issue affects F5 BIG-IP platforms with Cavium Nitrox SSL hardware acceleration cards, where a Virtual Server is configured with a Client SSL profile and uses Anonymous (ADH) or Ephemeral (DHE) Diffie-Hellman key exchange. If the Single DH use option is not enabled, the system may be vulnerable to crafted SSL/TLS Handshakes. This could result in a Pre-Master Secret (PMS) starting with a 0 byte, potentially leading to the recovery of plaintext messages. The BIG-IP TLS/SSL ADH/DHE implementation sends different error messages, acting as an oracle, and precise timing measurements may also expose this vulnerability.

Recommendations For versions 11.6.1 through 11.6.2, enable the Single DH use option in the Client SSL profile options list to mitigate the issue. For versions 12.1.0 through 12.1.2 HF1, enable the Single DH use option in the Client SSL profile options list to mitigate the issue. For versions 13.0.0 through 13.0.0 HF2, enable the Single DH use option in the Client SSL profile options list to mitigate the issue.

Fix

Side Channel Attack

Weakness Enumeration

CWE-203

Related Identifiers

CVE-2020-5929

Affected Products

F5 Big-Ip

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2020-5929 · Security Note
• https://support.f5.com/csp/article/K91158923 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2020-5929 · Vendor Advisory
• https://twitter.com/anya_tokugawa/status/1772999667690651844 · Twitter Post