Описание
etcd: tlsListener.acceptLoop spawns unbounded handshake goroutines with no deadline
Impact
What kind of vulnerability is it? Who is impacted?
A network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. Each connection spawns a goroutine in the etcd server process that blocks indefinitely inside tls.Conn.Handshake(), and each is tracked in the pending map. Unbounded goroutine and map growth exhausts memory in the etcd process, causing loss of availability for the etcd cluster (and, when etcd backs Kubernetes, the control plane).
Patches
Has the problem been patched? What versions should users upgrade to?
This vulnerability is patched in the following versions:
- etcd 3.7.1
- etcd 3.6.14
- etcd 3.5.33
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
If upgrading is not immediately possible, then restrict network access. Limit which hosts can reach etcd's client (gRPC) port via firewall rules or network policy, reducing who can attempt exploitation.
Reporter
VMware By Broadcom
Ссылки
- https://github.com/etcd-io/etcd/security/advisories/GHSA-6vch-q96h-7gc3
- https://github.com/etcd-io/etcd/pull/22130
- https://github.com/etcd-io/etcd/commit/2e07efce9745004eb4773cffaada9b5cdf77cff2
- https://github.com/etcd-io/etcd/commit/f73cba7d920019f91a1ea1f6697833e42731f057
- https://github.com/etcd-io/etcd/releases/tag/v3.5.33
- https://github.com/etcd-io/etcd/releases/tag/v3.6.14
- https://github.com/etcd-io/etcd/releases/tag/v3.7.1
Пакеты
go.etcd.io/etcd/v3
>= 3.7.0-alpha.0, < 3.7.1
3.7.1
go.etcd.io/etcd/v3
>= 3.6.0, < 3.6.14
3.6.14
go.etcd.io/etcd/v3
< 3.5.33
3.5.33
Связанные уязвимости
etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.5.33, 3.6.14, and 3.7.1, a network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. In client/pkg/transport/listener_tls.go, each connection handled by tlsListener.acceptLoop spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() and remains tracked in the pending map. Unbounded goroutine and map growth can exhaust memory in the etcd process, causing loss of availability for the cluster and, when etcd backs Kubernetes, the control plane. This issue is fixed in versions 3.5.33, 3.6.14, and 3.7.1.
etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.5.33, 3.6.14, and 3.7.1, a network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. In client/pkg/transport/listener_tls.go, each connection handled by tlsListener.acceptLoop spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() and remains tracked in the pending map. Unbounded goroutine and map growth can exhaust memory in the etcd process, causing loss of availability for the cluster and, when etcd backs Kubernetes, the control plane. This issue is fixed in versions 3.5.33, 3.6.14, and 3.7.1.
etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.5.33, 3.6.14, and 3.7.1, a network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. In client/pkg/transport/listener_tls.go, each connection handled by tlsListener.acceptLoop spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() and remains tracked in the pending map. Unbounded goroutine and map growth can exhaust memory in the etcd process, causing loss of availability for the cluster and, when etcd backs Kubernetes, the control plane. This issue is fixed in versions 3.5.33, 3.6.14, and 3.7.1.
etcd: `tlsListener.acceptLoop` spawns unbounded handshake goroutines with no deadline
etcd is a distributed key-value store for the data of a distributed sy ...