A flaw was found in etcd, where it does not perform any password length validation, which allows for very short passwords, such as those with a length of one. This flaw allows an attacker to guess or brute-force users' passwords with little computational effort. The highest threat from this vulnerability is to confidentiality.
etcd versions 3.2.x before 3.2.26 and 3.3.x before 3.3.11 are vulnerable to an improper authentication issue when role-based access control (RBAC) is used and client-cert-auth is enabled. If an etcd client server TLS certificate contains a Common Name (CN) which matches a valid RBAC username, a remote attacker may authenticate as that user with any valid (trusted) client certificate in a REST API request to the gRPC-gateway.
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
Vulnerability type Denial of Service
Detail The etcd gateway is a simple TCP proxy to allow for basic service discovery and access. However, it is possible to include the gateway address as an endpoint. This results in a denial of service, since the endpoint can become stuck in a loop of requesting itself until there are no more available file descriptors to accept connections on the gateway.
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