Advisories for Golang/Github.com/Etcd-Io/Etcd package

In etcd before versions 3.3.23 and 3.4.10, certain directory paths are created (etcd data directory and the directory path when provided to automatically generate self-signed certificates for TLS connections with clients) with restricted access permissions (700) by using the os.MkdirAll. This function does not perform any permission checks when a given directory path exists already. A possible workaround is to ensure the directories have the desired permission (700).

etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.4.26 and 3.5.9, the LeaseTimeToLive API allows access to key names (not value) associated to a lease when Keys parameter is true, even a user does not have read permission to the keys. The impact is limited to a cluster which enables auth (RBAC). Versions 3.4.26 and 3.5.9 fix this issue. There are no …

In etcd before versions 3.3.23 and 3.4.10, a large slice causes panic in decodeRecord method. The size of a record is stored in the length field of a WAL file and no additional validation is done on this data. Therefore, it is possible to forge an extremely large frame size that can unintentionally panic at the expense of any RAFT participant trying to decode the WAL.

etcd does not perform any password length validation, which allows for very short passwords, such as those with a length of one. This may allow an attacker to guess or brute-force users' passwords with little computational effort.

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.

In etcd, 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 with improved documentation and deprecation of the functionality.

DNS rebinding vulnerability found in etcd. An attacker can control his DNS records to direct to localhost, and trick the browser into sending requests to localhost (or any other address).

A cross-site request forgery flaw was found in etcd. An attacker can set up a website that tries to send a POST request to the etcd server and modify a key. Adding a key is done with PUT so it is theoretically safe (can't PUT from an HTML form or such) but POST allows creating in-order keys that an attacker can send.