CVE-2023-20071Network attack vector

Policy bypass via crafted FTP traffic

Published Nov 1, 2023 · Updated Aug 2, 2024

FTP inspection bypass in Cisco products using affected Snort engines allows remote attackers to evade policies with crafted FTP traffic. The FTP module fails to recognize and inspect crafted FTP traffic, but Cisco has not published the underlying parsing or detection error. No authentication or user interaction is required; successful traffic traverses the device without FTP inspection and can carry a malicious payload.

CVSS severity5.8
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

FTP inspection bypass in Cisco products using affected Snort engines allows remote attackers to evade policies with crafted FTP traffic. The FTP module fails to recognize and inspect crafted FTP traffic, but Cisco has not published the underlying parsing or detection error. No authentication or user interaction is required; successful traffic traverses the device without FTP inspection and can carry a malicious payload.

The record

CVE
CVE-2023-20071
Published
Nov 1, 2023
Updated
Aug 2, 2024
Vendor
ClamAV
Product
Cisco Cyber Vision
Classifications
CWE-1039, T1562.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.0.0
  2. Affected versionversion=3.0.1
  3. Affected versionversion=3.0.2
  4. Affected versionversion=3.0.3
  5. Affected versionversion=3.0.4
  6. Affected versionversion=3.0.5
  7. Affected versionversion=3.0.6
  8. Affected versionversion=3.1.0
  9. Affected versionversion=3.1.1
  10. Affected versionversion=3.1.2
  11. Affected versionversion=3.2.0
  12. Affected versionversion=3.2.1
  13. Affected versionversion=3.2.2
  14. Affected versionversion=3.2.3
  15. Affected versionversion=3.2.4
  16. Affected versionversion=4.0.0
  17. Affected versionversion=4.0.1
  18. Affected versionversion=4.0.2
  19. Affected versionversion=4.0.3
  20. Affected versionversion=4.1.0
  21. Affected versionversion=4.1.1
  22. Affected versionversion=4.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Cyber Visionversion=3.0.0; version=3.0.1; version=3.0.2; version=3.0.3; version=3.0.4; version=3.0.5; version=3.0.6; version=3.1.0; version=3.1.1; version=3.1.2; version=3.2.0; version=3.2.1; version=3.2.2; version=3.2.3; version=3.2.4; version=4.0.0; version=4.0.1; version=4.0.2; version=4.0.3; version=4.1.0; version=4.1.1; version=4.1.2
ClamAV · Cisco Umbrella Insights Virtual Applianceversion=N/A
ClamAV · Cisco Firepower Threat Defense Softwareversion=6.2.3; version=6.2.3.1; version=6.2.3.10; version=6.2.3.11; version=6.2.3.12; version=6.2.3.13; version=6.2.3.14; version=6.2.3.15; version=6.2.3.16; version=6.2.3.17; version=6.2.3.18; version=6.2.3.2; version=6.2.3.3; version=6.2.3.4; version=6.2.3.5; version=6.2.3.6; version=6.2.3.7; version=6.2.3.8; version=6.2.3.9; version=6.4.0; version=6.4.0.1; version=6.4.0.10; version=6.4.0.11; version=6.4.0.12; version=6.4.0.13; version=6.4.0.14; version=6.4.0.15; version=6.4.0.16; version=6.4.0.2; version=6.4.0.3; version=6.4.0.4; version=6.4.0.5; version=6.4.0.6; version=6.4.0.7; version=6.4.0.8; version=6.4.0.9; version=6.6.0; version=6.6.0.1; version=6.6.1; version=6.6.3; version=6.6.4; version=6.6.5; version=6.6.5.1; version=6.6.5.2; version=6.6.7; version=6.6.7.1; version=6.7.0; version=6.7.0.1; version=6.7.0.2; version=6.7.0.3; version=7.0.0; version=7.0.0.1; version=7.0.1; version=7.0.1.1; version=7.0.2; version=7.0.2.1; version=7.0.3; version=7.0.4; version=7.0.5; version=7.1.0; version=7.1.0.1; version=7.1.0.2; version=7.1.0.3; version=7.2.0; version=7.2.0.1; version=7.2.1; version=7.2.2; version=7.2.3; version=7.3.0; version=7.3.1; version=7.3.1.1
ClamAV · Cisco UTD Snort IPS Engine Softwareversion=16.12.1a; version=16.12.2; version=16.12.3; version=16.12.4; version=16.12.5; version=16.12.6; version=16.12.7; version=16.12.8; version=16.6.1; version=16.6.10; version=16.6.5; version=16.6.6; version=16.6.7a; version=16.6.9; version=17.10.1a; version=17.1.1; version=17.2.1r; version=17.3.1a; version=17.3.2; version=17.3.3; version=17.3.4a; version=17.3.5; version=17.3.6; version=17.3.7; version=17.4.1a; version=17.4.1b; version=17.4.2; version=17.5.1a; version=17.6.1a; version=17.6.2; version=17.6.3a; version=17.6.4; version=17.6.5; version=17.7.1a; version=17.7.2; version=17.8.1a; version=17.9.1a; version=17.9.2a; version=17.9.3a; version=3.17.0S; version=3.17.1S; version=Denali-16.3.3; version=Denali-16.3.4; version=Denali-16.3.5; version=Denali-16.3.7; version=Denali-16.3.9; version=Everest-16.6.2; version=Everest-16.6.3; version=Everest-16.6.4; version=Fuji-16.9.2; version=Fuji-16.9.3; version=Fuji-16.9.4; version=Fuji-16.9.5; version=Fuji-16.9.6; version=Fuji-16.9.7; version=Fuji-16.9.8

Published CVSS scores

5.8CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1039Inadequate Detection or Handling of Adversarial Input Perturbations in Automated Recognition Mechanism
T1562.001Impair Defenses: Disable or Modify Tools

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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