Adaptive Security Appliance SoftwareApplication · Cisco
CVE-2022-20866
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA logic error in how RSA keys are stored in memory on hardware cryptographic platforms in Cisco ASA and FTD software allows an unauthenticated remote attacker to extract RSA private keys via a Lenstra side-channel attack. The vulnerability affects approximately 5% of RSA keys with specific mathematical characteristics that make them susceptible to this attack.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Adaptive Security Appliance SoftwareApplication
>= 9.16.0, < 9.16.3.19>= 9.17.0, < 9.17.1.13>= 9.18.0, < 9.18.2
Secure Firewall Threat DefenseApplication
>= 7.0.0, < 7.0.4>= 7.1.0, < 7.2.0.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Cisco device type and software versionRun 'show version' or 'show module' to confirm whether the device runs Cisco ASA or Cisco Firepower Threat Defense (FTD) software, and note the full version numberAffected if The device runs ASA version 9.16.0 through 9.16.3.18, 9.17.0 through 9.17.1.12, or 9.18.0 through 9.18.1; OR FTD version 7.0.0 through 7.0.3 or 7.1.0 through 7.2.0
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Confirm hardware cryptographic module is in useRun 'show crypto key mypubkey rsa' to list RSA keys configured on the device. On hardware platforms, also check 'show hardware encryption' or 'show crypto ipsec sa' to confirm hardware-based crypto acceleration is enabledAffected if RSA keys are generated and stored on the device hardware crypto module (not software-only keys)
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Determine if RSA keys were generated on affected versionsReview configuration management records, change logs, or the 'show running-config | include crypto key' output to identify when RSA key pairs were created. Check if keys were generated while running an affected versionAffected if RSA key pairs were generated or imported while the device was running any affected version listed above
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Check for indicators of key compromiseRun 'show crypto key mypubkey rsa' and compare key moduli against known weak or malformed keys. Test TLS/SSL connections from the device to verify signature verification succeeds. Check system logs for errors related to cryptographic operationsAffected if Any RSA key appears malformed, shows unusual properties, or TLS signature verification fails unexpectedly
A user is affected if the device runs an affected ASA or FTD version AND uses hardware-based RSA keys generated on that vulnerable version, with keys potentially exhibiting mathematical weaknesses detectable through comparison or verification failures.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped7.0.47.2.0.19.16.3.19
Apply the relevant Cisco security updates for ASA and FTD software. After patching, audit RSA keys for indicators of compromise (malformed/invalid keys or failed TLS signature verification) and regenerate affected keys as a precautionary measure.
ASA: 9.16.3.19+ / 9.17.1.13+ / 9.18.2+ ; FTD: 7.0.4+ / 7.2.0.1+
- Identify the currently installed Cisco ASA Software or FTD Software version using 'show version' command
- Determine which software branch (9.16, 9.17, 9.18 for ASA; 7.0, 7.1, 7.2 for FTD) the device is running
- For ASA Software: If running 9.16.x, upgrade to 9.16.3.19 or later; if running 9.17.x, upgrade to 9.17.1.13 or later; if running 9.18.x, upgrade to 9.18.2 or later
- For FTD Software: If running 7.0.x, upgrade to 7.0.4 or later; if running 7.1.x, upgrade to 7.2.0.1 or later
- After upgrade, regenerate all RSA keys on the device as a precaution using 'crypto key generate rsa' command
- Verify the new RSA keys are properly generated and functioning
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Adaptive Security Appliance Software
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-20866 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2022-20866 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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