CVE-2022-21698

client_golang is the instrumentation library for Go applications in Prometheus, and the promhttp package in client_golang provides tooling around HTTP servers and clients. In client_golang prior to version 1.11.1, HTTP server is susceptible to a Denial of Service through unbounded cardinality, and potential memory exhaustion, when handling requests with non-standard HTTP methods. In order to be affected, an instrumented software must use any of promhttp.InstrumentHandler* middleware except RequestsInFlight; not filter any specific methods (e.g GET) before middleware; pass metric with method label name to our middleware; and not have any firewall/LB/proxy that filters away requests with unknown method. client_golang version 1.11.1 contains a patch for this issue. Several workarounds are available, including removing the method label name from counter/gauge used in the InstrumentHandler; turning off affected promhttp handlers; adding custom middleware before promhttp handler that will sanitize the request method given by Go http.Request; and using a reverse proxy or web application firewall, configured to only allow a limited set of methods.

Weakness

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.

Affected Software

Extended Description

Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system. There are at least three distinct scenarios which can commonly lead to resource exhaustion:

Resource exhaustion problems are often result due to an incorrect implementation of the following situations:

Potential Mitigations

• Mitigation of resource exhaustion attacks requires that the target system either:

• The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

• The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/147.html
• https://cwe.mitre.org/data/definitions/227.html
• https://cwe.mitre.org/data/definitions/492.html

References

• https://github.com/prometheus/client_golang/pull/962
• https://github.com/prometheus/client_golang/pull/987
• https://github.com/prometheus/client_golang/releases/tag/v1.11.1
• https://github.com/prometheus/client_golang/security/advisories/GHSA-cg3q-j54f-5p7p
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2IK53GWZ475OQ6ENABKMJMTOBZG6LXUR/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2PFW6Q2LXXWTFRTMTRN4ZGADFRQPKJ3D/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36GUEPA5TPSC57DZTPYPBL6T7UPQ2FRH/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3L6GDN5S5QZSCFKWD3GKL2RDZQ6B4UWA/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4KDETHL5XCT6RZN2BBNOCEXRZ2W3SFU3/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5OGNAFVXSMTTT2UPH6CS3IH6L3KM42Q7/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7V7I72LSQ3IET3QJR6QPAVGJZ4CBDLN5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AK7CJBCGERCRXYUR2EWDSSDVAQMTAZGX/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DLUJZV3HBP56ADXU6QH2V7RNYUPMVBXQ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FY3N7H6VSDZM37B4SKM2PFFCUWU7QYWN/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HLAQRRGNSO5MYCPAXGPH2OCSHOGHSQMQ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J5WPM42UR6XIBQNQPNQHM32X7S4LJTRX/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KBMVIQFKQDSSTHVVJWJ4QH6TW3JVB7XZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MH6ALXEQXIFQRQFNJ5Y2MJ5DFPIX76VN/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RN7JGC2LVHPEGSJYODFUV5FEKPBVG4D7/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SASRKYHT5ZFSVMJUQUG3UAEQRJYGJKAR/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZKORFJTRRDJCWBTJPISKKCVMMMJBIRLG/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZY2SLWOQR4ZURQ7UBRZ7JIX6H6F5JHJR/
• https://github.com/prometheus/client_golang/pull/962
• https://github.com/prometheus/client_golang/pull/987
• https://github.com/prometheus/client_golang/releases/tag/v1.11.1
• https://github.com/prometheus/client_golang/security/advisories/GHSA-cg3q-j54f-5p7p
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2IK53GWZ475OQ6ENABKMJMTOBZG6LXUR/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2PFW6Q2LXXWTFRTMTRN4ZGADFRQPKJ3D/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36GUEPA5TPSC57DZTPYPBL6T7UPQ2FRH/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3L6GDN5S5QZSCFKWD3GKL2RDZQ6B4UWA/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4KDETHL5XCT6RZN2BBNOCEXRZ2W3SFU3/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5OGNAFVXSMTTT2UPH6CS3IH6L3KM42Q7/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7V7I72LSQ3IET3QJR6QPAVGJZ4CBDLN5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AK7CJBCGERCRXYUR2EWDSSDVAQMTAZGX/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DLUJZV3HBP56ADXU6QH2V7RNYUPMVBXQ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FY3N7H6VSDZM37B4SKM2PFFCUWU7QYWN/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HLAQRRGNSO5MYCPAXGPH2OCSHOGHSQMQ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J5WPM42UR6XIBQNQPNQHM32X7S4LJTRX/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KBMVIQFKQDSSTHVVJWJ4QH6TW3JVB7XZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MH6ALXEQXIFQRQFNJ5Y2MJ5DFPIX76VN/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RN7JGC2LVHPEGSJYODFUV5FEKPBVG4D7/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SASRKYHT5ZFSVMJUQUG3UAEQRJYGJKAR/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZKORFJTRRDJCWBTJPISKKCVMMMJBIRLG/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZY2SLWOQR4ZURQ7UBRZ7JIX6H6F5JHJR/