Cisco Secure Email TLS algorithmic complexity

Summaryinfo

A vulnerability was found in Cisco Secure Email. It has been declared as problematic. Impacted is an unknown function of the component TLS Handler. Executing a manipulation can lead to algorithmic complexity. The identification of this vulnerability is CVE-2020-3548. The attack may be launched remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Cisco Secure Email (version now known). This vulnerability affects some unknown processing of the component TLS Handler. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. The CWE definition for the vulnerability is CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. As an impact it is known to affect availability. CVE summarizes:

A vulnerability in the Transport Layer Security (TLS) protocol implementation of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause high CPU usage on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient processing of incoming TLS traffic. An attacker could exploit this vulnerability by sending a series of crafted TLS packets to an affected device. A successful exploit could allow the attacker to trigger a prolonged state of high CPU utilization. The affected device would still be operative, but response time and overall performance may be degraded.There are no workarounds that address this vulnerability.

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability was named CVE-2020-3548 since 12/12/2019. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading eliminates this vulnerability.

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Productinfo

Vendor

• Cisco

Name

• Secure Email

License

• commercial

Website

• Vendor: https://www.cisco.com/

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