CVE-2017-12231: Technical Deep-Dive (Auto Refreshed)

Generated on 2026-03-23T22:21:44.086Z. This file is automatically regenerated every 30 minutes by the CVE AI enrichment job using web sources (NVD, MITRE, CISA KEV, GitHub).

Executive Technical Summary

A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected device via IPv4 packets. An attacker could exploit this vulnerability by sending a crafted H.323 RAS packet through an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to use an application layer gateway with NAT (NAT ALG) for H.323 RAS messages. By default, a NAT ALG is enabled for H.323 RAS messages. Cisco Bug IDs: CSCvc57217.

• Context preserved from previous revision: A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected device via IPv4 packets. An attacker could exploit this vulnerability by sending a crafted H.323 RAS packet through an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to use an application layer gateway with NAT (NAT ALG) for H.323 RAS messages. By default, a NAT ALG is enabled for H.323 RAS messages. Cisco Bug IDs: CSCvc57217. Notes: Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

Technical Details

• CVE: CVE-2017-12231
• KEV date added: 2022-03-03
• KEV due date: 2022-03-24
• NVD published: 2017-09-29
• NVD modified: 2026-01-14
• MITRE modified: 2026-01-14
• CVSS base score: 7.5
• CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
• CVSS exploitability score: 3.9
• CVSS impact score: 3.6
• Attack vector: Network
• Attack complexity: Low
• Privileges required: None
• User interaction: None
• Scope: Unchanged
• Confidentiality impact: None
• Integrity impact: None
• Availability impact: High

Versions and Products Impacted

• cisco / ios (versions: >= 12.4, <= 15.6)
• n/a / Cisco IOS (versions: Cisco IOS)

Weakness Classification

• CWE-399
• NVD-CWE-noinfo

Repositories for Lab Validation (Public Examples)

• Ostorlab/KEV | stars: 608 | updated: 2026-03-23 | https://github.com/Ostorlab/KEV
  Notes: Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

People and Organizations Mentioned

• cisco
• IOS software
• Ostorlab

Practical Defensive Validation (Authorized Only)

1. Use only isolated environments and systems you own or are explicitly authorized to test.
2. Snapshot infrastructure before validation and preserve baseline logs (EDR, SIEM, OS, app).
3. Inventory cisco / ios (versions: >= 12.4, <= 15.6) assets and confirm exact vulnerable versions with automated checks.
4. Patch in staged environments and validate closure with scanners + service health checks.
5. Map detections to MITRE ATT&CK tactics relevant to your environment and tune alert quality.

References

• NVD record: https://nvd.nist.gov/vuln/detail/CVE-2017-12231
• MITRE CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12231
• CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• CISA KEV JSON feed: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
• KEV notes: https://nvd.nist.gov/vuln/detail/CVE-2017-12231
• http://www.securityfocus.com/bid/101039
• http://www.securitytracker.com/id/1039449
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-nat
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12231
• Repository example: https://github.com/Ostorlab/KEV

This content is for defensive security training and authorized validation only.