diff mbox series

[v4,1/3] Unbound: Enable DNS cache poisoning mitigation

Message ID 20180910142126.5265-1-peter.mueller@link38.eu
State Accepted
Headers
Series [v4,1/3] Unbound: Enable DNS cache poisoning mitigation |

Commit Message

Peter Müller Sept. 11, 2018, 12:21 a.m. UTC 
  By default, Unbound neither keeps track of the number of unwanted
replies nor initiates countermeasures if they become too large (DNS
cache poisoning).

This sets the maximum number of tolerated unwanted replies to
1M, causing the cache to be flushed afterwards. (Upstream documentation
recommends 10M as a threshold, but this turned out to be ineffective
against attacks in the wild.)

See https://nlnetlabs.nl/documentation/unbound/unbound.conf/ for
details. This version of the patch uses 1M as threshold instead of
5M and supersedes the first and second version.

Signed-off-by: Peter Müller <peter.mueller@link38.eu>
---
 config/unbound/unbound.conf | 3 +++
 1 file changed, 3 insertions(+)

Comments

Michael Tremer Sept. 11, 2018, 1:35 a.m. UTC | #1 
Merged!

On Mon, 2018-09-10 at 16:21 +0200, Peter Müller wrote:
> By default, Unbound neither keeps track of the number of unwanted
> replies nor initiates countermeasures if they become too large (DNS
> cache poisoning).
> 
> This sets the maximum number of tolerated unwanted replies to
> 1M, causing the cache to be flushed afterwards. (Upstream documentation
> recommends 10M as a threshold, but this turned out to be ineffective
> against attacks in the wild.)
> 
> See https://nlnetlabs.nl/documentation/unbound/unbound.conf/ for
> details. This version of the patch uses 1M as threshold instead of
> 5M and supersedes the first and second version.
> 
> Signed-off-by: Peter Müller <peter.mueller@link38.eu>
> ---
>  config/unbound/unbound.conf | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/config/unbound/unbound.conf b/config/unbound/unbound.conf
> index 3f724d8f7..ce9ddcd62 100644
> --- a/config/unbound/unbound.conf
> +++ b/config/unbound/unbound.conf
> @@ -61,6 +61,9 @@ server:
>  	harden-algo-downgrade: no
>  	use-caps-for-id: no
>  
> +	# Harden against DNS cache poisoning
> +	unwanted-reply-threshold: 1000000
> +
>  	# Listen on all interfaces
>  	interface-automatic: yes
>  	interface: 0.0.0.0
diff mbox series

Patch

diff --git a/config/unbound/unbound.conf b/config/unbound/unbound.conf
index 3f724d8f7..ce9ddcd62 100644
--- a/config/unbound/unbound.conf
+++ b/config/unbound/unbound.conf
@@ -61,6 +61,9 @@  server:
 	harden-algo-downgrade: no
 	use-caps-for-id: no
 
+	# Harden against DNS cache poisoning
+	unwanted-reply-threshold: 1000000
+
 	# Listen on all interfaces
 	interface-automatic: yes
 	interface: 0.0.0.0