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Known exploited vulnerability

CVE-2023-20269

criticalCVSS 3.1 9.1In CISA KEVRansomwareEPSS 27%Published · Cisco

The short answer

CVE-2023-20269 affects Cisco Cisco Adaptive Security Appliance (ASA) Software and is rated critical (CVSS 9.1). CISA added it to the Known Exploited Vulnerabilities catalog on 2023-09-13: attackers are using it, so patch it first.

What it is

A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or an authenticated, remote attacker to establish a clientless SSL VPN session with an unauthorized user. This vulnerability is due to improper separation of authentication, authorization, and accounting (AAA) between the remote access VPN feature and the HTTPS management and site-to-site VPN features. An attacker could exploit this vulnerability by specifying a default connection profile/tunnel group while conducting a brute force attack or while establishing a clientless SSL VPN session using valid credentials. A successful exploit could allow the attacker to achieve one or both of the following: Identify valid credentials that could then be used to establish an unauthorized remote access VPN session. Establish a clientless SSL VPN session (only when running Cisco ASA Software Release 9.16 or earlier). Notes: Establishing a client-based remote access VPN tunnel is not possible as these default connection profiles/tunnel groups do not and cannot have an IP address pool configured. This vulnerability does not allow an attacker to bypass authentication. To successfully establish a remote access VPN session, valid credentials are required, including a valid second factor if multi-factor authentication (MFA) is configured. Cisco will release software updates that address this vulnerability. There are workarounds that address this vulnerability.

Weakness: CWE-288, CWE-863.

Severity

9.1 critical

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

Exploited (CISA KEV)

Yes, since Sep 13, 2023

Federal due date Oct 4, 2023

EPSS, next 30 days

27%

Higher than 98% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

What CISA says to do

Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.

Affected products

Cisco Adaptive Security Appliance (ASA) Software, Cisco Firepower Threat Defense Software. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2023-20269 being exploited?

Yes. CISA added CVE-2023-20269 to its Known Exploited Vulnerabilities catalog on 2023-09-13, with a federal remediation due date of 2023-10-04. CISA lists it as used in ransomware campaigns.

How do I fix CVE-2023-20269?

CISA's required action: Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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