Cisco Secure Firewall Threat Defense
CVE-2020-3577
A vulnerability in the ingress packet processing path of Cisco Firepower Threat Defense (FTD) Software for interfaces that are configured either as Inline Pair or in Passive mode could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation when Ethernet frames are processed. An attacker could exploit this vulnerability by sending malicious Ethernet frames through an affected device. A successful exploit could allow the attacker do either of the following: Fill the /ngfw partition on the device: A full /ngfw partition could result in administrators being unable to log in to the device (including logging in through the console port) or the device being unable to boot up correctly. Note: Manual intervention is required to recover from this situation. Customers are advised to contact the Cisco Technical Assistance Center (TAC) to help recover a device in this condition. Cause a process crash: The process crash would cause the device to reload. No manual intervention is necessary to recover the device after the reload.
What this means for your business
- It affects Cisco Secure Firewall Threat Defense. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it from inside the same network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 36% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Cisco Secure Firewall Threat Defense, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
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Scoring
- CVSS
- 7.4 (v3.1)
- Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- Weakness
- CWE-20
- Assigned by
- psirt@cisco.com
Dates
- Published
- 2020-10-21
- Last modified
- 2026-08-11
- Sources
- NVD
Affected products
- Cisco Secure Firewall Threat Defense- 6.3.0.6, 6.4.0 - 6.4.0.10, 6.5.0 - 6.5.0.5, 6.6.0 - 6.6.1
As listed in the NVD configuration data. Not a statement about your estate.