CVE-2020-15136: Improper authentication in etcd
Vulnerability type Cryptography
Workarounds Refer to the gateway documentation. The vulnerability was spotted due to unclear documentation of how the gateway handles endpoints validation.
Detail When starting a gateway, TLS authentication will only be attempted on endpoints identified in DNS SRV records for a given domain, which occurs in the discoverEndpoints function. No authentication is performed against endpoints provided in the --endpoints flag. The auditors has noted that appropriate documentation of this validation functionality plus deprecation of this misleading functionality is an acceptable path forward. References Find out more on this vulnerability in the security audit report
For more information If you have any questions or comments about this advisory: Contact the etcd security committee
Other sources
A flaw was found in etcd. The gateway TLS authentication is only applied to endpoints detected in DNS SRV records. When starting a gateway, TLS authentication will only be attempted on endpoints identified in DNS SRV records for a given domain, which occurs in the discoverEndpoints function. No authentication is performed against endpoints provided in the --endpoints flag.
In ectd before versions 3.4.10 and 3.3.23, gateway TLS authentication is only applied to endpoints detected in DNS SRV records. When starting a gateway, TLS authentication will only be attempted on endpoints identified in DNS SRV records for a given domain, which occurs in the discoverEndpoints function. No authentication is performed against endpoints provided in the --endpoints flag. This has been fixed in versions 3.4.10 and 3.3.23 with improved documentation and deprecation of the functionality.
In etcd before versions 3.4.10 and 3.3.23, gateway TLS authentication is only applied to endpoints detected in DNS SRV records. When starting a gateway, TLS authentication will only be attempted on endpoints identified in DNS SRV records for a given domain, which occurs in the discoverEndpoints function. No authentication is performed against endpoints provided in the --endpoints flag. This has been fixed in versions 3.4.10 and 3.3.23 with improved documentation and deprecation of the functionality.
References: https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/gateway.md https://github.com/etcd-io/etcd/security/advisories/GHSA-wr2v-9rpq-c35q
— Red Hat
Affected Software
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2020-15136?
CVE-2020-15136 is considered a moderate severity vulnerability due to its impact on cryptographic operations.
How do I fix CVE-2020-15136?
To mitigate CVE-2020-15136, upgrade etcd to version 3.4.10 or later, or ensure you are using a version lower than 3.3.23.
What software is affected by CVE-2020-15136?
CVE-2020-15136 affects various versions of the etcd software, specifically those above 3.3.0 and lower than or equal to 3.3.23 and 3.4.10.
What are the potential consequences of CVE-2020-15136?
Exploitation of CVE-2020-15136 can lead to improper validation of endpoint security, which may compromise cryptographic operations.
Is there a workaround for CVE-2020-15136?
There are no specific workarounds for CVE-2020-15136; the recommended action is to upgrade to a secure version of etcd.