CVE Catalog

CVE-2023-20177

MediumCVSS 4.0
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.53%

42th percentile - higher than 42% of all known CVEs

Summary

A vulnerability in the SSL file policy implementation of Cisco FTD Software during SSL/TLS inspection with a URL Category could allow an unauthenticated, remote attacker to cause the Snort 3 detection engine to unexpectedly restart. This is due to a logic error when inspecting SSL/TLS connections with URL Category configured. An attacker could send a crafted SSL/TLS connection to trigger a reload, resulting in bypass or DoS.

Risk Assessment

Reloading the Snort 3 engine may cause inspection gaps, potentially leading to policy bypass or temporary loss of protection, as well as packet drops.

Recommendation

Apply Cisco updates for FTD. Review SSL/TLS policy configurations and consider temporarily disabling URL categories if feasible.

Other vulnerabilities in Cisco Firepower Threat Defense Software

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Original NVD description (English source)

A vulnerability in the SSL file policy implementation of Cisco Firepower Threat Defense (FTD) Software that occurs when the SSL/TLS connection is configured with a URL Category and the Snort 3 detection engine could allow an unauthenticated, remote attacker to cause the Snort 3 detection engine to unexpectedly restart. This vulnerability exists because a logic error occurs when a Snort 3 detection engine inspects an SSL/TLS connection that has either a URL Category configured on the SSL file policy or a URL Category configured on an access control policy with TLS server identity discovery enabled. Under specific, time-based constraints, an attacker could exploit this vulnerability by sending a crafted SSL/TLS connection through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 detection engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. The Snort 3 detection engine will restart automatically. No manual intervention is required.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS