CVE-2023-20107: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Low-Entropy Keys Vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-03-23 · updated 2026-08-11
Weakness: CWE-332

Description

A vulnerability in the deterministic random bit generator (DRBG), also known as pseudorandom number generator (PRNG), in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco ASA 5506-X, ASA 5508-X, and ASA 5516-X Firewalls could allow an unauthenticated, remote attacker to cause a cryptographic collision, enabling the attacker to discover the private key of an affected device. This vulnerability is due to insufficient entropy in the DRBG for the affected hardware platforms when generating cryptographic keys. An attacker could exploit this vulnerability by generating a large number of cryptographic keys on an affected device and looking for collisions with target devices. A successful exploit could allow the attacker to impersonate an affected target device or to decrypt traffic secured by an affected key that is sent to or from an affected target device.

Affected products

Cisco Adaptive Security Appliance: before 9.12.1 — fixed in 9.12.1
Cisco Firepower Threat Defense Software: before 6.4.0 — fixed in 6.4.0

How to fix

Upgrade to a fixed version: Cisco Adaptive Security Appliance 9.12.1; Cisco Firepower Threat Defense Software 6.4.0. Check the vendor advisory for mitigations.

References

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