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What is CVE-2022-20866?A high-severity flaw in Firepower Threat Defense, explained.

High severity34 affected products
The short answer

CVE-2022-20866 is a high-severity flaw (CVSS 7.5) in Firepower Threat Defense from Cisco, published on 10 August 2022. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 18%. If you run an affected version, plan in the vendor’s fix.

Check if it affects you →How to fix it

Published 10 August 2022. Record last updated 7 November 2023. We keep this page's data up to date.

What it does

What is CVE-2022-20866? In plain terms.

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data.

The official description

A vulnerability in the handling of RSA keys on devices running Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to retrieve an RSA private key. This vulnerability is due to a logic error when the RSA key is stored in memory on a hardware platform that performs hardware-based cryptography. An attacker could exploit this vulnerability by using a Lenstra side-channel attack against the targeted device. A successful exploit could allow the attacker to retrieve the RSA private key. The following conditions may be observed on an affected device: This vulnerability will apply to approximately 5 percent of the RSA keys on a device that is running a vulnerable release of Cisco ASA Software or Cisco FTD Software; not all RSA keys are expected to be affected due to mathematical calculations applied to the RSA key. The RSA key could be valid but have specific characteristics that make it vulnerable to the potential leak of the RSA private key. If an attacker obtains the RSA private key, they could use the key to impersonate a device that is running Cisco ASA Software or Cisco FTD Software or to decrypt the device traffic. See the Indicators of Compromise section for more information on the detection of this type of RSA key. The RSA key could be malformed and invalid. A malformed RSA key is not functional, and a TLS client connection to a device that is running Cisco ASA Software or Cisco FTD Software that uses the malformed RSA key will result in a TLS signature failure, which means a vulnerable software release created an invalid RSA signature that failed verification. If an attacker obtains the RSA private key, they could use the key to impersonate a device that is running Cisco ASA Software or Cisco FTD Software or to decrypt the device traffic.

What kind of flaw is it?

  • CWE-203Observable Discrepancy
CVSS 3.1 scoreHigh · 7.5

How an attack on it works

Read straight from its severity rating, translated out of the shorthand.

  • Where an attacker can beAnywhere on the internet
  • How hard it is to pull offEasy: no special conditions
  • Login needed firstNo login needed
  • Does someone have to clickNo, nobody has to do anything
  • What an attacker getsCan read data

Severity vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploitation

Is CVE-2022-20866 being exploited? Not that we know of.

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 18%. That can change at any time, which is why we keep watching.

Known to be exploitedNoNot on the list of exploited flaws today
Chance of use in the next 30 days18%Its EPSS score, from the latest forecast

Timeline

  1. Published
  2. Record last updated
How Precursor Intelligence ranks it
59out of 100Medium

CVE-2022-20866 scores 59. Action: Plan remediation.

We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:

  • Evidence it is being exploitedBiggest factor
  • How severe it isStrong factor
  • How widely exposed it isSmaller factor
  • Threat activity around itSmaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.

When CVE-2022-20866 matches software you track, it lands in your list with its score and the reasons behind it.

See your own ranked list →
Affected products

Who is affected by CVE-2022-20866? 34 products.

The published record lists 34 products from 1 vendor. Versions are shown as published: "7.0.0 to before 7.0.4" means from 7.0.0 up to, but not including, 7.0.4. If you run one of these, check your version, then go to the fix below.

Remediation

How do I fix CVE-2022-20866? Four steps.

  1. Check whether you run itCompare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
  2. Apply the vendor’s fixInstall the update named in the vendor’s advisory. We’ve put the advisory first in the list.
  3. If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
  4. Keep an eye on itTrack the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

References

1 link
Precursor Intelligence

Does CVE-2022-20866 affect you? We'll keep checking.

Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.

  1. Tell us what you runPick your software from a list, or let us work it out from your website.
  2. We match it to every flawOver 400,000 published flaws, checked against your list.
  3. Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
  4. Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
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FAQ

Common questions, answered plainly.

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CVE-2022-20866 is a high-severity flaw in Firepower Threat Defense from Cisco, published on 10 August 2022. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data.

It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2022-20866 is 59 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 18%. That can change at any time, which is why we keep watching.

For Firepower Threat Defense from Cisco: 7.0.0 to before 7.0.4, 7.1.0 to before 7.2.0.1. The record lists 34 products in all, each with its versions, under "Who is affected" on this page.

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

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