Vulnerability identifier: #VU47945

Vulnerability risk: Medium

CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-3555

CWE-ID: CWE-404

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

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 watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. A remote attacker can send a high rate of specially crafted SIP traffic through an affected device and cause a denial of service condition on the target system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Cisco Adaptive Security Appliance (ASA): 9.6 - 9.14

Cisco Firepower Threat Defense (FTD): 6.2.2, 6.2.3, 6.3.0, 6.4.0, 6.5.0, 6.6.0

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-sipdos-3DGvdjvg

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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.