Denial of service in Cisco ASA AnyConnect SSL/TLS VPN

1) Improper Resource Shutdown or Release

EUVDB-ID: #VU82663

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-20042

CWE-ID: CWE-404 - Improper Resource Shutdown or Release

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an error within the SSL/TLS session handling process in the AnyConnect SSL VPN feature. A remote attacker can send specially crafted SSL/TLS traffic to an affected device and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Cisco Adaptive Security Appliance (ASA): before 9.20.1

External links

http://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ssl-dos-kxG8mpUA
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCwd62859

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.