Exploited vulnerability · CISA KEV

Is CVE-2024-20353 exploited? Yes: in CISA KEV since 24 Apr 2024

Gociux · Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2024-20353, Cisco ASA and FTD Denial of Service Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 24 Apr 2024, the day it was published. It affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD), an internet-facing product of the kind attackers use for initial access. If you run it, CISA's required action is: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

exploitedYesCISA KEV · 24 Apr 2024

ransomwareNot knownno confirmed use

EPSStop 1%among the most likely CVEs to be exploited

severity8.6CVSS 3.1 · high

US federal due1 May 2024BOD 22-01 deadline

What it is

Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain an infinite loop vulnerability that can lead to remote denial of service condition.

Vendor	Cisco (103 exploited CVEs in KEV)
Product	Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
Vulnerability	Cisco ASA and FTD Denial of Service Vulnerability
Weakness	CWE-835
Published	24 Apr 2024
Added to KEV	24 Apr 2024
Reported by (CNA)	cisco

What to do

Check whether you run it. Look for Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) in your asset inventory, including appliances and cloud images. Stack check lists every exploited Cisco CVE at once.
Apply the fix. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 24 Apr 2024.
Get told next time. Email alerts when CISA adds a CVE for Cisco.

Other exploited CVEs in Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)

CVE-2024-20481: Cisco ASA and FTD Denial-of-Service Vulnerability (24 Oct 2024)
CVE-2024-20359: Cisco ASA and FTD Privilege Escalation Vulnerability (24 Apr 2024)
CVE-2020-3259: Cisco ASA and FTD Information Disclosure Vulnerability (15 Feb 2024)
CVE-2020-3452: Cisco ASA and FTD Read-Only Path Traversal Vulnerability (3 Nov 2021)
CVE-2020-3580: Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability (3 Nov 2021)

References

Questions

Is CVE-2024-20353 being exploited?

Yes. CISA added CVE-2024-20353 to the Known Exploited Vulnerabilities catalog on 24 Apr 2024, which means there is reliable evidence of exploitation in the wild.

Is CVE-2024-20353 used in ransomware attacks?

CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.

How do I fix CVE-2024-20353?

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Check Cisco's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) and watch it for signs of compromise.

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in April 2024 · Cisco scorecard · act-now radar.

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