CVE-2024-20359: Cisco ASA and FTD Privilege Escalation Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-04-24, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-05-01; treat that as the outer limit, not the target.
• EPSS 19.4%, percentile 97: FIRST’s model estimates a 19.4% chance of exploitation activity in the next 30 days, higher than 97% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.

What it is

A vulnerability in a legacy capability that allowed for the preloading of VPN clients and plug-ins and that has been available in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary code with root-level privileges. Administrator-level privileges are required to exploit this vulnerability. This vulnerability is due to improper validation of a file when it is read from system flash memory. An attacker could exploit this vulnerability by copying a crafted file to the disk0: file system of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the affected device after the next reload of the device, which could alter system behavior. Because the injected code could persist across device reboots, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High.

CISA’s summary

Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain a privilege escalation vulnerability that can allow local privilege escalation from Administrator to root.

Weakness type: CWE-94.

Product: Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) · Assigned by: cisco · Published: 2024-04-24

Affected and fixed versions

Severity scores

• Attack vector: local access needed
• Attack complexity: low
• Privileges required: high (admin)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2024-04-24; federal due date 2024-05-01. Known ransomware use: Unknown.
• CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
• CISA SSVC assessment: exploitation active, automatable no, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 19.43% probability of exploitation activity in the next 30 days; percentile 97.

Timeline

• 2024-04-24 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2024-04-24 — CVE record published by cisco
• 2024-05-01 — CISA remediation deadline for US federal agencies
• 2025-10-21 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. Listed in CISA KEV notes (sec.cloudapps.cisco.com) sec.cloudapps.cisco.com

Vulnerability records

1. CVE.org record CVE-2024-20359 cve.org
2. NVD entry CVE-2024-20359 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

1. blog.talosintelligence.com blog.talosintelligence.com

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