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Vendor advisorySeverity 5.3 medium
Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Low-Entropy Keys Vulnerability
cisco-sa-asa5500x-entropy-6v9bHVYP · Cisco · March 22, 2023
Summary
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.
Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability for some affected configurations.
From Cisco (vendor's own words, quoted), quoted as published. Check the source before acting.
What to do
Cisco has released software updates that address this vulnerability.
Vendor fix or mitigation, quoted from the advisory.
Each CVE in this advisory
| CVE | Severity | Known exploited | Exploit likelihood |
|---|---|---|---|
| CVE-2023-20107 | 5.3 medium | No | 0.7% |
Severity from the advisory (CVSS), known exploitation from CISA's catalog, exploit likelihood from EPSS (next 30 days).
Affected products
| Vendor | Product |
|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software |
| Cisco | Cisco ASA 5500-X Series Firewalls |
Why it's on these mode pages
- Maritime: Vendor table: Cisco (network and remote-access gear used in every mode, all modes) (matched by rule)
- Pipeline: Vendor table: Cisco (network and remote-access gear used in every mode, all modes) (matched by rule)
- Freight rail: Vendor table: Cisco (network and remote-access gear used in every mode, all modes) (matched by rule)
- Passenger rail and transit: Vendor table: Cisco (network and remote-access gear used in every mode, all modes) (matched by rule)
- Highway and motor carrier: Vendor table: Cisco (network and remote-access gear used in every mode, all modes) (matched by rule)
- Postal and parcel: Vendor table: Cisco (network and remote-access gear used in every mode, all modes) (matched by rule)
Change history
- March 22, 2023: Initial public release.
- November 9, 2026: First collected by Watch
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