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Vendor advisorySeverity 5.8 medium
Cisco Firepower Threat Defense Software SMB Protocol Snort 3 Detection Engine Bypass and Denial of Service Vulnerability
cisco-sa-ftd-smbsnort3-dos-pfOjOYUV · Cisco · November 1, 2023
Summary
A vulnerability in the interaction between the Server Message Block (SMB) protocol preprocessor and the Snort 3 detection engine for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass the configured policies or cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to improper error-checking when the Snort 3 detection engine is processing SMB traffic. An attacker could exploit this vulnerability by sending a crafted SMB packet stream through an affected device. A successful exploit could allow the attacker to cause the Snort process to reload, resulting in a DoS condition.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is part of the November 2023 release of the Cisco ASA, FTD, and FMC Security Advisory Bundled publication. For a complete list of the advisories and links to them, see Cisco Event Response: November 2023 Semiannual Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74985"].
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-2023-20270 | 5.8 medium | No | 0.9% |
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 Threat Defense (FTD) Software |
| Cisco | Cisco Firepower 2100 Series |
| Cisco | Cisco Firepower 1000 Series |
| Cisco | Cisco 3000 Series Industrial Security Appliances (ISA) |
| Cisco | Cisco Firepower 9000 Series |
| Cisco | Cisco Firepower 4100 Series |
| Cisco | Cisco Secure Firewall Threat Defense Virtual |
| Cisco | Cisco Secure Firewall 3100 Series |
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
- November 1, 2023: Initial public release.
- November 9, 2026: First collected by Watch
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