Vulnerability identifier: #VU57758

Vulnerability 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-2021-40117

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco Adaptive Security Appliance (ASA)
Hardware solutions / Security hardware applicances
Cisco Firepower Threat Defense (FTD)
Hardware solutions / Security hardware applicances
ASA 5500-X Series Firewalls
Other software / Other software solutions

Vendor: Cisco Systems, Inc

Description

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

The vulnerability exists due to a boundary error when processing SSL/TLS packets in SSL VPN interface. A remote attacker can send a specially crafted HTTPS request, trigger memory corruption and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco Adaptive Security Appliance (ASA): 9.7 - 9.15.1.15

ASA 5500-X Series Firewalls: All versions

Cisco Firepower Threat Defense (FTD): 6.7.0 - 6.7.0.2, 6.6.0 - 6.6.4, 6.5.0 - 6.5.0.5, 6.4.0 - 6.4.0.12, 6.3.0 - 6.3.0.6, 6.2.3 - 6.2.3.16, 6.2.2 - 6.2.2.1

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-dos-4ygzLKU9
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCvy43187

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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.