Cyber Resilience

CVE-2023-20107

Cisco Adaptive Security Appliance ≤ 9.12.1

Published
23 March 2023
Modified
11 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0072 51th percentile
Risk Priority 61 floored blend · peak EPSS

Summary

CVE-2023-20107 is a high-severity Insufficient Entropy in PRNG (CWE-332) vulnerability in Cisco Adaptive Security Appliance. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Weaken Encryption (T1600); ranked in the top 49% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-332CWE-331

Related Threats

MITRE ATT&CK Enterprise Techniques

T1600 Weaken Encryption Defense Impairment
Adversaries may compromise a network device’s encryption capability in order to bypass encryption that would otherwise protect data communications.
attack.mitre.org →
T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1110.001 Password Guessing Credential Access
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.
attack.mitre.org →
T1110.002 Password Cracking Credential Access
Adversaries may use password cracking to attempt to recover usable credentials, such as plaintext passwords, when credential material such as password hashes are obtained.
attack.mitre.org →
T1600.001 Reduce Key Space Defense Impairment
Adversaries may reduce the level of effort required to decrypt data transmitted over the network by reducing the cipher strength of encrypted communications.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-20331Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20101Same product: Cisco Secure Firewall Threat Defense
CVE-2016-6367Same product: Cisco Asa 5506-X
CVE-2026-20050Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20083Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20267Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20031Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20177Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20070Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20351Same product: Cisco Secure Firewall Threat Defense

Affected Assets

cisco
adaptive security appliance
≤ 9.12.1
cisco
secure firewall threat defense
≤ 6.4.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 9 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.5.2
  • V11.3.4
  • V7.2.3
  • V11.5.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-12 Cryptographic Key Establishment and Management
addresses: CWE-331 CWE-332

Approved key-establishment methods mandate sufficient entropy during key generation, eliminating entropy-starved keys.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices explicitly include vetted RNG and entropy sources, directly preventing this weakness while covering many other development concerns.

PR.AA-03 partial match
prevents

Password-strength policies implicitly require sufficient entropy, but the control addresses authentication rather than algorithmic randomness.

PR.DS-01 partial match
prevents

Proper encryption for data-at-rest requires sufficient entropy for keys/nonces; eliminating the weakness therefore supports but does not fully realize the control.

PR.DS-02 partial match
prevents

Cryptographic protection of data-in-transit depends on adequate entropy; the weakness directly undermines the control's effectiveness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.24 Use of cryptography mostly match
prevents

Mandates use of cryptography that must rely on sufficient entropy sources.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect insufficient entropy in PRNG implementations before deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC requires selection of approved cryptographic primitives including proper RNG sources.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles include use of approved cryptographic modules with adequate entropy sources.

A.8.28 Secure coding partial match
prevents

Secure coding standards prohibit weak PRNG usage and require cryptographically secure random functions.

A.8.5 Secure authentication partial match
degrades

Requires secure authentication mechanisms that depend on unpredictable secrets.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-331
  • V-248563 The OL 8 SSH server must be configured to use strong entropy. prevents CWE-331, CWE-332
RHEL 7 (1 rule)
  • V-204497 The Red Hat Enterprise Linux operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-331
RHEL 8 (2 rules)
  • V-230223 RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-331
  • V-230253 RHEL 8 must ensure the SSH server uses strong entropy. prevents CWE-332

References