Waitress 1.4.2 Header Regular Expression resource consumption

Summaryinfo

A vulnerability has been found in Waitress 1.4.2 and classified as problematic. This affects an unknown part of the component Header Handler. This manipulation as part of Regular Expression causes resource consumption. This vulnerability is registered as CVE-2020-5236. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability classified as problematic was found in Waitress 1.4.2. Affected by this vulnerability is an unknown part of the component Header Handler. The manipulation as part of a Regular Expression leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

Waitress version 1.4.2 allows a DOS attack When waitress receives a header that contains invalid characters. When a header like "Bad-header: xxxxxxxxxxxxxxx\x10" is received, it will cause the regular expression engine to catastrophically backtrack causing the process to use 100% CPU time and blocking any other interactions. This allows an attacker to send a single request with an invalid header and take the service offline. This issue was introduced in version 1.4.2 when the regular expression was updated to attempt to match the behaviour required by errata associated with RFC7230. The regular expression that is used to validate incoming headers has been updated in version 1.4.3, it is recommended that people upgrade to the new version of Waitress as soon as possible.

The weakness was published 02/04/2020 (GitHub Repository). It is possible to read the advisory at github.com. This vulnerability is known as CVE-2020-5236 since 01/02/2020. The attack can be launched remotely. A single authentication is necessary for exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• Waitress

Version

• 1.4.2

License

• open-source

CPE 2.3info

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• 🔍

CPE 2.2info

• 🔍
• 🔍

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